National Toxicology Program

National Toxicology Program
https://ntp.niehs.nih.gov/go/2665

TDMS Study 05052-01 Pathology Tables


                                     INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)
                                                         2,4-DICHLOROPHENOL


NTP Experiment-Test: 05052-01                                                                                     Report: PEIRPT03
Study Type: CHRONIC                                                                                               Date: 09/07/94
Route: DOSED FEED                                                                                                 Time: 20:09:14




       Facility:  Battelle Columbus Laboratory

       Chemical CAS #:  120-83-2

       Lock Date:  None

       Cage Range:  All

       Reasons For Removal:    All

       Removal Date Range:     All

       Treatment Groups:       Include All
































a  Number of animals examined microscopically at site and number of animals with lesion

                                                             Page   1

NTP Experiment-Test: 05052-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         2,4-DICHLOROPHENOL                                    Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 20:09:14  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   0 PPM        2500 PPM     5000 PPM                                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially In Study                          50           50           50                                                  
  Early Deaths                                                                                                                      
    Moribund                                          14            3            8                                                  
    Dead                                               2            4            2                                                  
  Survivors                                                                                                                         
    Terminal Sacrifice                                34           43           40                                                  
  Animals Examined Microscopically                    50           50           50                                                  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large                                    (48)                      (49)                                                
      Colon, Parasite Metazoan, Single                                           1 (2%)                                             
      Rectum, Parasite Metazoan                        2 (4%)                                                                       
      Rectum, Parasite Metazoan, Multifocal            1 (2%)                                                                       
      Rectum, Parasite Metazoan, Single                                          2 (4%)                                             
   Intestine Small                                    (48)                      (49)                                                
      Ileum, Peyer's Patch, Hyperplasia, Lymphoid,                                                                                  
           Multifocal                                                            1 (2%)                                             
   Liver                                              (50)         (23)         (50)                                                
      Angiectasis, Focal                               1 (2%)                                                                       
      Angiectasis, Multifocal                                       1 (4%)       1 (2%)                                             
      Basophilic Focus, Multiple                      33 (66%)     14 (61%)     42 (84%)                                            
      Basophilic Focus, Single                         2 (4%)       2 (9%)       1 (2%)                                             
      Clear Cell Focus                                              2 (9%)                                                          
      Clear Cell Focus, Multiple                                                 1 (2%)                                             
      Clear Cell Focus, Single                         2 (4%)                    3 (6%)                                             
      Cyst                                                          1 (4%)                                                          
      Hemorrhage, Acute, Multifocal                    1 (2%)                                                                       
      Hyperplasia, Focal                                                         1 (2%)                                             
      Inflammation, Focal, Granulomatous                            2 (9%)                                                          
      Inflammation, Focal, Membranoproliferative                                 1 (2%)                                             
      Inflammation, Granulomatous, Multifocal         26 (52%)      7 (30%)     22 (44%)                                            
      Inflammation, Multifocal, Subacute                            2 (9%)                                                          
      Bile Duct, Hyperplasia, Multifocal               8 (16%)      2 (9%)       7 (14%)                                            
      Centrilobular, Pigmentation, Hemosiderin,                                                                                     
           Multifocal                                                            1 (2%)                                             
      Hepatocyte, Degeneration, Cystic, Focal          1 (2%)       3 (13%)                                                         
      Hepatocyte, Necrosis, Acute, Multifocal          3 (6%)                    1 (2%)                                             
      Hepatocyte, Necrosis, Multifocal                                           2 (4%)                                             
      Hepatocyte, Vacuolization Cytoplasmic,                                                                                        
          Multifocal                                   9 (18%)                   6 (12%)                                            
      Hepatocyte, Centrilobular, Necrosis,                                                                                          
          Multifocal, Subacute                                                   1 (2%)                                             
      Left Lateral Lobe, Angiectasis, Focal                                      1 (2%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    2                                                              
NTP Experiment-Test: 05052-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         2,4-DICHLOROPHENOL                                    Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 20:09:14  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   0 PPM        2500 PPM     5000 PPM                                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Median Lobe, Atrophy, Chronic, Multifocal                                  1 (2%)                                             
      Periportal, Hematopoietic Cell Proliferation,                                                                                 
           Multifocal                                  2 (4%)                                                                       
      Periportal, Infiltration Cellular, Acute,                                                                                     
           Multifocal, Lymphocyte                                                1 (2%)                                             
      Sinusoid, Subserosa, Congestion, Acute,                                                                                       
          Multifocal                                                             1 (2%)                                             
   Mesentery                                          (2)                       (2)                                                 
      Inflammation, Chronic, Multifocal                1 (50%)                                                                      
      Inflammation, Focal, Granulomatous               1 (50%)                                                                      
      Inflammation, Granulomatous, Multifocal                                    1 (50%)                                            
   Pancreas                                           (50)         (48)         (49)                                                
      Infiltration Cellular, Multifocal, Lymphocyte                              1 (2%)                                             
      Acinus, Atrophy, Focal                           5 (10%)     10 (21%)      2 (4%)                                             
      Acinus, Atrophy, Multifocal                     15 (30%)      8 (17%)      6 (12%)                                            
   Stomach                                            (49)                      (50)                                                
      Forestomach, Hyperkeratosis, Multifocal                                    1 (2%)                                             
      Forestomach, Hyperplasia, Multifocal,                                                                                         
          Squamous                                                               1 (2%)                                             
      Glandular, Ulcer, Acute, Multifocal              1 (2%)                                                                       
   Tooth                                                                        (1)                                                 
      Peridontal Tissue, Inflammation, Chronic                                                                                      
          Active, Multifocal                                                     1 (100%)                                           
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)                      (50)                                                
      Atrium Left, Thrombosis, Multifocal, Subacute                              1 (2%)                                             
      Myocardium, Degeneration, Chronic, Multifocal   40 (80%)                  38 (76%)                                            
      Myocardium, Inflammation, Acute, Multifocal      1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Gland                                      (50)         (49)         (49)                                                
      Bilateral, Cortex, Atrophy, Diffuse                           1 (2%)                                                          
      Bilateral, Cortex, Congestion, Multifocal        1 (2%)       1 (2%)                                                          
      Bilateral, Cortex, Congestion, Multifocal,                                                                                    
           Subacute                                    1 (2%)                                                                       
      Bilateral, Cortex, Degeneration, Diffuse,                                                                                     
           Fatty                                                    1 (2%)                                                          
      Bilateral, Cortex, Degeneration, Fatty,                                                                                       
          Multifocal                                                3 (6%)       1 (2%)                                             
      Bilateral, Cortex, Hyperplasia, Focal            1 (2%)                                                                       
      Bilateral, Cortex, Hyperplasia, Multifocal       1 (2%)       7 (14%)      2 (4%)                                             
      Bilateral, Medulla, Hyperplasia, Multifocal      1 (2%)                    2 (4%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    3                                                              
NTP Experiment-Test: 05052-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         2,4-DICHLOROPHENOL                                    Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 20:09:14  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   0 PPM        2500 PPM     5000 PPM                                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Bilateral, Medulla, Infiltration Cellular,                                                                                    
           Acute, Multifocal, Lymphocyte                                         1 (2%)                                             
      Capsule, Hyperplasia, Focal                                   1 (2%)                                                          
      Cortex, Cyst                                     1 (2%)                                                                       
      Cortex, Cytoplasmic Alteration, Focal            3 (6%)       3 (6%)       1 (2%)                                             
      Cortex, Cytoplasmic Alteration, Multifocal                    1 (2%)                                                          
      Cortex, Degeneration, Cystic, Focal              1 (2%)       1 (2%)                                                          
      Cortex, Degeneration, Fatty, Focal              12 (24%)      7 (14%)      6 (12%)                                            
      Cortex, Degeneration, Fatty, Multifocal          2 (4%)       1 (2%)       3 (6%)                                             
      Cortex, Hyperplasia, Focal                       8 (16%)      6 (12%)     11 (22%)                                            
      Cortex, Hyperplasia, Multifocal                  2 (4%)       3 (6%)       2 (4%)                                             
      Cortex, Hypertrophy, Focal                       2 (4%)                    1 (2%)                                             
      Cortex, Karyomegaly, Focal                       3 (6%)       2 (4%)                                                          
      Cortex, Necrosis, Multifocal                     1 (2%)                                                                       
      Cortex, Right, Atrophy, Multifocal                            1 (2%)                                                          
      Medulla, Cyst                                                 1 (2%)                                                          
      Medulla, Hyperplasia, Focal                      2 (4%)                    2 (4%)                                             
      Medulla, Hyperplasia, Multifocal                 1 (2%)                    5 (10%)                                            
      Medulla, Karyomegaly, Focal                                   1 (2%)                                                          
   Parathyroid Gland                                  (36)                      (39)                                                
      Hyperplasia, Glandular, Multifocal                                         1 (3%)                                             
      Hyperplasia, Multifocal                          1 (3%)                                                                       
   Pituitary Gland                                    (50)         (32)         (48)                                                
      Cyst, Multiple                                                1 (3%)                                                          
      Pars Distalis, Cyst                              1 (2%)       3 (9%)       2 (4%)                                             
      Pars Distalis, Cyst, Multiple                   12 (24%)      7 (22%)      6 (13%)                                            
      Pars Distalis, Cyst, Single                      1 (2%)                    1 (2%)                                             
      Pars Distalis, Hemorrhage, Focal                 1 (2%)       1 (3%)                                                          
      Pars Distalis, Hemorrhage, Multifocal            4 (8%)                    4 (8%)                                             
      Pars Distalis, Hemorrhage, Multifocal,                                                                                        
          Subacute                                                               2 (4%)                                             
      Pars Distalis, Hyperplasia, Diffuse                                        1 (2%)                                             
      Pars Distalis, Hyperplasia, Focal                5 (10%)      1 (3%)       2 (4%)                                             
      Pars Distalis, Hyperplasia, Multifocal           2 (4%)                    4 (8%)                                             
      Pars Distalis, Necrosis, Chronic, Multifocal                  1 (3%)                                                          
   Thyroid Gland                                      (50)                      (49)                                                
      C-Cell, Hyperplasia, Focal                                                 1 (2%)                                             
      C-Cell, Hyperplasia, Multifocal                 30 (60%)                  25 (51%)                                            
      Follicle, Cyst, Single                           2 (4%)                                                                       
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 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    4                                                              
NTP Experiment-Test: 05052-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         2,4-DICHLOROPHENOL                                    Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 20:09:14  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   0 PPM        2500 PPM     5000 PPM                                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (38)         (2)          (40)                                                
      Cyst                                                                       1 (3%)                                             
      Cyst, Multiple                                   2 (5%)                                                                       
      Hyperplasia, Focal, Glandular                                              3 (8%)                                             
      Inflammation, Chronic Active, Focal              1 (3%)                    1 (3%)                                             
      Inflammation, Chronic Active, Multifocal         1 (3%)                                                                       
      Inflammation, Multifocal, Subacute               1 (3%)                                                                       
      Inflammation, Multifocal, Suppurative                                      1 (3%)                                             
      Necrosis, Acute, Focal                           1 (3%)                                                                       
      Necrosis, Chronic Active, Focal                  1 (3%)                                                                       
   Ovary                                              (50)         (5)          (49)                                                
      Necrosis, Coagulative, Multifocal                             1 (20%)                                                         
      Bilateral, Periovarian Tissue, Cyst              1 (2%)                                                                       
      Bilateral, Follicle, Cyst                        1 (2%)                                                                       
      Follicle, Cyst                                                             2 (4%)                                             
      Follicle, Cyst, Multiple                         1 (2%)                    5 (10%)                                            
      Follicle, Cyst, Single                           2 (4%)                                                                       
      Germinal Epithelium, Mineralization,                                                                                          
          Multifocal                                   1 (2%)                                                                       
      Left, Follicle, Cyst                             1 (2%)                                                                       
      Periovarian Tissue, Cyst                         1 (2%)       1 (20%)      3 (6%)                                             
      Periovarian Tissue, Right, Cyst                  1 (2%)       1 (20%)                                                         
      Periovarian Tissue, Left, Cyst                                2 (40%)      1 (2%)                                             
   Uterus                                             (50)         (10)         (50)                                                
      Abscess                                          2 (4%)                                                                       
      Inflammation, Chronic Active, Multifocal         1 (2%)                                                                       
      Bilateral, Lumen, Ectasia                                     1 (10%)                                                         
      Bilateral, Lumen, Ectasia, Multifocal                                      1 (2%)                                             
      Cervix, Diverticulum                             2 (4%)       1 (10%)      1 (2%)                                             
      Cervix, Fibrosis, Chronic, Multifocal                                      1 (2%)                                             
      Cervix, Inflammation, Chronic Active,                                                                                         
          Multifocal                                                1 (10%)      1 (2%)                                             
      Cervix, Inflammation, Multifocal, Suppurative    1 (2%)                                                                       
      Cervix, Prolapse, Multifocal                                  1 (10%)                                                         
      Endometrium, Hemorrhage, Multifocal                           1 (10%)                                                         
      Endometrium, Hyperplasia, Cystic, Glandular,                                                                                  
           Multifocal                                 24 (48%)                  32 (64%)                                            
      Lumen, Ectasia, Focal                                                      1 (2%)                                             
      Lumen, Ectasia, Multifocal                       3 (6%)                    5 (10%)                                            
      Lumen, Hemorrhage, Focal, Subacute                            2 (20%)                                                         
      Lumen, Right, Ectasia, Focal                     1 (2%)       1 (10%)                                                         
      Lumen, Right, Ectasia, Multifocal                1 (2%)       1 (10%)      1 (2%)                                             
      Lumen, Left, Ectasia, Focal                                                1 (2%)                                             
      Serosa, Inflammation, Chronic, Focal             1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    5                                                              
NTP Experiment-Test: 05052-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         2,4-DICHLOROPHENOL                                    Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 20:09:14  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   0 PPM        2500 PPM     5000 PPM                                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Blood                                              (12)                      (8)                                                 
      Neutrophilia                                                               1 (13%)                                            
   Bone Marrow                                        (50)                      (49)                                                
      Hyperplasia, Multifocal, Neutrophil              1 (2%)                    3 (6%)                                             
      Hyperplasia, Multifocal, Reticulum Cell          5 (10%)                                                                      
      Inflammation, Granulomatous, Multifocal                                    1 (2%)                                             
      Myelofibrosis, Multifocal                                                  2 (4%)                                             
      Erythroid Cell, Hypoplasia, Multifocal                                     1 (2%)                                             
   Lymph Node                                         (48)         (47)         (50)                                                
      Hemorrhage                                       1 (2%)                                                                       
      Inflammation, Granulomatous, Multifocal                       1 (2%)                                                          
      Cortex, Mandibular, Cyst, Multiple                            1 (2%)                                                          
      Mandibular, Angiectasis, Multifocal                                        1 (2%)                                             
      Mandibular, Depletion Lymphoid, Multifocal                                 1 (2%)                                             
      Mandibular, Hemorrhage, Multifocal               9 (19%)      5 (11%)     16 (32%)                                            
      Mandibular, Hyperplasia, Histiocytic,                                                                                         
          Multifocal                                                             1 (2%)                                             
      Mandibular, Hyperplasia, Lymphoid, Multifocal    5 (10%)                   3 (6%)                                             
      Mandibular, Hyperplasia, Multifocal, Plasma                                                                                   
          Cell                                         4 (8%)       8 (17%)      2 (4%)                                             
      Mandibular, Inflammation, Chronic, Multifocal                 1 (2%)       4 (8%)                                             
      Mandibular, Inflammation, Granulomatous,                                                                                      
           Multifocal                                  4 (8%)       7 (15%)      4 (8%)                                             
      Mandibular, Pigmentation, Hemosiderin,                                                                                        
          Multifocal                                                1 (2%)       1 (2%)                                             
      Mediastinal, Depletion Lymphoid, Multifocal      1 (2%)                                                                       
      Mediastinal, Hemorrhage, Multifocal              6 (13%)                   2 (4%)                                             
      Mediastinal, Inflammation, Chronic,                                                                                           
          Multifocal                                                             1 (2%)                                             
      Mediastinal, Inflammation, Granulomatous,                                                                                     
           Multifocal                                  6 (13%)                   4 (8%)                                             
   Spleen                                             (50)         (48)         (50)                                                
      Lymphoid Follicle, Depletion Lymphoid,                                                                                        
          Multifocal                                   2 (4%)       2 (4%)       1 (2%)                                             
      Lymphoid Follicle, Inflammation,                                                                                              
          Granulomatous, Multifocal                    2 (4%)                                                                       
      Red Pulp, Congestion, Focal                      1 (2%)       1 (2%)                                                          
      Red Pulp, Fibrosis, Focal                                     1 (2%)                                                          
      Red Pulp, Hematopoietic Cell Proliferation,                                                                                   
           Multifocal                                 25 (50%)     17 (35%)     30 (60%)                                            
      Red Pulp, Hematopoietic Cell Proliferation,                                                                                   
           Multiple                                                 1 (2%)                                                          
      Red Pulp, Inflammation, Chronic Active,                                                                                       
          Multifocal                                                1 (2%)                                                          
      Red Pulp, Inflammation, Granulomatous,                                                                                        
          Multifocal                                                1 (2%)       2 (4%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    6                                                              
NTP Experiment-Test: 05052-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         2,4-DICHLOROPHENOL                                    Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 20:09:14  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   0 PPM        2500 PPM     5000 PPM                                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Red Pulp, Necrosis, Acute, Focal                 1 (2%)                                                                       
      Red Pulp, Necrosis, Acute, Multifocal                                      1 (2%)                                             
      Red Pulp, Pigmentation, Hemosiderin,                                                                                          
          Multifocal                                   2 (4%)       3 (6%)       2 (4%)                                             
   Thymus                                             (39)                      (47)                                                
      Depletion Lymphoid, Multifocal                  30 (77%)                  36 (77%)                                            
      Pigmentation, Hemosiderin, Multifocal                                      1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (46)         (9)          (46)                                                
      Acinus, Hyperplasia, Cystic, Multifocal         26 (57%)                  27 (59%)                                            
      Acinus, Hyperplasia, Cystic, Multiple            1 (2%)                                                                       
   Skin                                               (50)         (2)          (50)                                                
      Abdominal, Ulcer, Acute, Focal                                             1 (2%)                                             
      Axillary, Subcutaneous Tissue, Inflammation,                                                                                  
           Chronic Active, Multifocal                  1 (2%)                                                                       
      Hindlimb, Subcutaneous Tissue, Inflammation,                                                                                  
           Chronic Active, Granulomatous                            1 (50%)                                                         
      Hindlimb, Epidermis, Acanthosis, Multifocal                   1 (50%)                                                         
      Hindlimb, Epidermis, Hyperkeratosis,                                                                                          
          Multifocal                                                1 (50%)                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (49)                      (50)                                                
      Femur, Osteopetrosis, Multifocal                 7 (14%)                  11 (22%)                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)                      (48)                                                
      Cerebellum, Hemorrhage, Acute, Focal             1 (2%)                                                                       
      Cerebellum, Hemorrhage, Multifocal                                         1 (2%)                                             
      Cerebrum, Compression, Focal                     9 (18%)                   7 (15%)                                            
      Cerebrum, Hemorrhage, Focal                                                1 (2%)                                             
      Cerebrum, Perivascular Cuffing, Focal                                      1 (2%)                                             
      Medulla, Hemorrhage, Focal                                                 1 (2%)                                             
      Medulla, Hemorrhage, Multifocal                  1 (2%)                                                                       
      Ventricle, Hydrocephalus, Multifocal             3 (6%)                    5 (10%)                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    7                                                              
NTP Experiment-Test: 05052-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         2,4-DICHLOROPHENOL                                    Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 20:09:14  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   0 PPM        2500 PPM     5000 PPM                                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (1)          (50)                                                
      Congestion, Acute, Diffuse                                    1 (100%)                                                        
      Congestion, Acute, Multifocal                    2 (4%)                                                                       
      Hemorrhage, Acute, Multifocal                    2 (4%)                                                                       
      Pigmentation, Hemosiderin, Multifocal                                      1 (2%)                                             
      Alveolar Epithelium, Hyperplasia, Focal                                    2 (4%)                                             
      Alveolar Epithelium, Hyperplasia, Multifocal     1 (2%)                                                                       
      Bronchiole, Epithelium, Hyperplasia,                                                                                          
          Multifocal                                                             1 (2%)                                             
      Interstitium, Inflammation, Acute, Focal         1 (2%)                                                                       
      Interstitium, Inflammation, Acute, Multifocal                              1 (2%)                                             
      Interstitium, Inflammation, Chronic, Focal                                 1 (2%)                                             
      Interstitium, Inflammation, Multifocal,                                                                                       
          Subacute                                                               1 (2%)                                             
   Nose                                               (45)                      (45)                                                
      Nasolacrimal Duct, Inflammation, Focal,                                                                                       
          Subacute                                     5 (11%)                   7 (16%)                                            
      Nasolacrimal Duct, Inflammation, Multifocal,                                                                                  
           Subacute                                   18 (40%)                   9 (20%)                                            
      Respiratory Epithelium, Degeneration,                                                                                         
          Multifocal                                  19 (42%)                  17 (38%)                                            
      Submucosa, Respiratory Epithelium,                                                                                            
          Congestion, Acute, Multifocal                1 (2%)                                                                       
      Submucosa, Respiratory Epithelium,                                                                                            
          Inflammation, Multifocal, Subacute          21 (47%)                  24 (53%)                                            
   Trachea                                            (49)                      (48)                                                
      Wall, Hemorrhage, Multifocal                                               1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (4)          (1)          (4)                                                 
      Hemorrhage, Acute, Multifocal                    1 (25%)                                                                      
      Lens, Cataract                                                1 (100%)     3 (75%)                                            
      Lens, Cataract, Multifocal                       1 (25%)                                                                      
      Retina, Atrophy, Multifocal                      1 (25%)      1 (100%)     3 (75%)                                            
   Harderian Gland                                    (40)                      (42)                                                
      Inflammation, Focal, Subacute                                              2 (5%)                                             
      Inflammation, Multifocal, Subacute              15 (38%)                   8 (19%)                                            
      Bilateral, Inflammation, Multifocal, Subacute    1 (3%)                    2 (5%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    8                                                              
NTP Experiment-Test: 05052-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         2,4-DICHLOROPHENOL                                    Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 20:09:14  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   0 PPM        2500 PPM     5000 PPM                                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (1)          (49)                                                
      Bilateral, Nephropathy, Chronic, Multifocal     46 (92%)                  33 (67%)                                            
      Bilateral, Nephropathy, Multifocal                                         1 (2%)                                             
      Cortex, Casts, Single                            1 (2%)                                                                       
      Cortex, Infarct, Focal                                                     1 (2%)                                             
      Cortex, Inflammation, Chronic, Focal             1 (2%)                    1 (2%)                                             
      Cortex, Left, Cyst, Single                                    1 (100%)     1 (2%)                                             
      Medulla, Left, Cyst, Multiple                    1 (2%)                                                                       
      Renal Tubule, Degeneration, Acute, Multifocal    2 (4%)                    1 (2%)                                             
      Renal Tubule, Hyperplasia, Focal                                           1 (2%)                                             
      Renal Tubule, Vacuolization Cytoplasmic,                                                                                      
           Multifocal                                  1 (2%)                                                                       
   Urinary Bladder                                    (50)         (1)          (48)                                                
      Calculus Micro Observation Only                                            1 (2%)                                             
      Lumen, Calculus Gross Observation                             1 (100%)                                                        
      Mucosa, Hyperplasia, Chronic, Multifocal                      1 (100%)                                                        
      Mucosa, Hyperplasia, Multifocal                                            1 (2%)                                             
      Mucosa, Hyperplasia, Multifocal, Squamous                                  1 (2%)                                             
      Mucosa, Metaplasia, Multifocal, Squamous                                   1 (2%)                                             
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    9                                                              
NTP Experiment-Test: 05052-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         2,4-DICHLOROPHENOL                                    Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 20:09:14  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially In Study                          50           50           50                                                  
  Early Deaths                                                                                                                      
    Moribund                                          12           16           12                                                  
    Dead                                               5            9            6                                                  
  Survivors                                                                                                                         
    Terminal Sacrifice                                33           25           32                                                  
  Animals Examined Microscopically                    50           50           50                                                  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Esophagus                                          (50)                      (50)                                                
      Submucosa, Inflammation, Chronic, Multifocal                               1 (2%)                                             
   Intestine Large                                    (47)         (1)          (47)                                                
      Colon, Peyer's Patch, Hyperplasia, Lymphoid,                                                                                  
           Multifocal                                                            3 (6%)                                             
      Colon, Mesothelium, Inflammation, Chronic                                                                                     
          Active, Multifocal                                        1 (100%)                                                        
      Lamina Propria, Rectum, Inflammation,                                                                                         
          Multifocal, Subacute                                      1 (100%)                                                        
      Peyer's Patch, Rectum, Hyperplasia, Lymphoid,                                                                                 
           Multifocal                                                            1 (2%)                                             
      Rectum, Parasite Metazoan                        1 (2%)                                                                       
      Rectum, Mesothelium, Inflammation, Chronic                                                                                    
          Active, Multifocal                                        1 (100%)                                                        
   Intestine Small                                    (47)         (1)          (47)                                                
      Necrosis                                                      1 (100%)                                                        
      Jejunum, Inflammation, Chronic Active,                                                                                        
          Multifocal, Proliferative                                 1 (100%)                                                        
      Jejunum, Necrosis                                             1 (100%)                                                        
      Jejunum, Lamina Propria, Metaplasia,                                                                                          
          Multifocal, Osseous                                       1 (100%)                                                        
      Jejunum, Subserosa, Diverticulum                              1 (100%)                                                        
      Mucosa, Necrosis                                              1 (100%)                                                        
   Liver                                              (50)         (50)         (50)                                                
      Angiectasis, Focal                               4 (8%)                                                                       
      Angiectasis, Multifocal                          1 (2%)                                                                       
      Basophilic Focus                                 1 (2%)                    3 (6%)                                             
      Basophilic Focus, Focal                          1 (2%)                                                                       
      Basophilic Focus, Multiple                      14 (28%)     12 (24%)     11 (22%)                                            
      Basophilic Focus, Single                         2 (4%)       2 (4%)       1 (2%)                                             
      Clear Cell Focus                                 1 (2%)                                                                       
      Clear Cell Focus, Focal                                                    1 (2%)                                             
      Clear Cell Focus, Multiple                       1 (2%)       1 (2%)       4 (8%)                                             
      Clear Cell Focus, Single                                      1 (2%)       3 (6%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   10                                                              
NTP Experiment-Test: 05052-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         2,4-DICHLOROPHENOL                                    Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 20:09:14  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Eosinophilic Focus                                                         2 (4%)                                             
      Eosinophilic Focus, Multiple                     3 (6%)                    3 (6%)                                             
      Eosinophilic Focus, Single                       1 (2%)       1 (2%)       1 (2%)                                             
      Hyperplasia, Focal                               1 (2%)                                                                       
      Inflammation, Granulomatous, Multifocal          5 (10%)      7 (14%)      2 (4%)                                             
      Mixed Cell Focus                                 1 (2%)                                                                       
      Bile Duct, Hyperplasia, Chronic, Multifocal      1 (2%)                                                                       
      Bile Duct, Hyperplasia, Cystic, Multifocal                                 1 (2%)                                             
      Bile Duct, Hyperplasia, Multifocal              35 (70%)     30 (60%)     23 (46%)                                            
      Bile Duct, Hyperplasia, Multifocal, Nodular      1 (2%)                                                                       
      Capsule, Hematocyst, Single                                                1 (2%)                                             
      Centrilobular, Necrosis, Acute, Multifocal                                 1 (2%)                                             
      Hepatocyte, Cytoplasmic Alteration, Focal        1 (2%)                    2 (4%)                                             
      Hepatocyte, Cytoplasmic Alteration,                                                                                           
          Multifocal                                                2 (4%)                                                          
      Hepatocyte, Degeneration, Cystic, Focal         10 (20%)      7 (14%)      6 (12%)                                            
      Hepatocyte, Degeneration, Cystic, Multifocal     9 (18%)      5 (10%)      2 (4%)                                             
      Hepatocyte, Necrosis, Acute, Multifocal                                    2 (4%)                                             
      Hepatocyte, Necrosis, Focal                                                1 (2%)                                             
      Hepatocyte, Necrosis, Multifocal                                           1 (2%)                                             
      Hepatocyte, Necrosis, Multifocal, Subacute       1 (2%)                                                                       
      Hepatocyte, Vacuolization Cytoplasmic, Focal                               1 (2%)                                             
      Hepatocyte, Vacuolization Cytoplasmic,                                                                                        
          Multifocal                                   8 (16%)      8 (16%)     10 (20%)                                            
      Left Lateral Lobe, Necrosis, Acute, Focal                     1 (2%)                                                          
      Median Lobe, Hepatocyte, Degeneration, Fatty,                                                                                 
           Multifocal                                                            1 (2%)                                             
   Mesentery                                          (3)          (2)          (2)                                                 
      Inflammation, Granulomatous, Multifocal                       1 (50%)                                                         
      Necrosis, Chronic, Focal                                                   1 (50%)                                            
      Fat, Necrosis                                                              1 (50%)                                            
      Fat, Necrosis, Acute, Multifocal                 1 (33%)                                                                      
      Fat, Necrosis, Chronic, Multifocal               1 (33%)                                                                      
   Pancreas                                           (49)                      (49)                                                
      Acinus, Atrophy, Focal                           2 (4%)                    7 (14%)                                            
      Acinus, Atrophy, Multifocal                     27 (55%)                  16 (33%)                                            
      Acinus, Cytoplasmic Alteration, Focal            2 (4%)                                                                       
      Acinus, Cytoplasmic Alteration, Multifocal                                 1 (2%)                                             
      Artery, Inflammation, Chronic Active,                                                                                         
          Multifocal                                                             1 (2%)                                             
      Duct, Ectasia, Focal                             1 (2%)                                                                       
      Duct, Ectasia, Multifocal                        1 (2%)                    1 (2%)                                             
   Salivary Glands                                    (50)                      (50)                                                
      Acinus, Atrophy, Focal                           1 (2%)                                                                       
      Acinus, Atrophy, Multifocal                      1 (2%)                                                                       
   Stomach                                            (49)         (2)          (49)                                                
      Forestomach, Acanthosis, Focal                                1 (50%)                                                         
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   11                                                              
NTP Experiment-Test: 05052-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         2,4-DICHLOROPHENOL                                    Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 20:09:14  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Forestomach, Acanthosis, Multifocal              2 (4%)                                                                       
      Forestomach, Hyperkeratosis, Focal                            1 (50%)                                                         
      Forestomach, Hyperkeratosis, Multifocal          1 (2%)                                                                       
      Forestomach, Ulcer, Focal, Subacute              1 (2%)                                                                       
      Forestomach, Ulcer, Multifocal, Subacute         1 (2%)                                                                       
      Forestomach, Muscularis, Inflammation,                                                                                        
          Chronic, Multifocal                                                    1 (2%)                                             
      Forestomach, Muscularis, Mineralization,                                                                                      
           Multifocal                                  1 (2%)                                                                       
      Glandular, Inflammation, Chronic, Multifocal                               1 (2%)                                             
      Glandular, Necrosis, Acute, Focal                1 (2%)                                                                       
      Glandular, Necrosis, Acute, Multifocal                        2 (100%)     1 (2%)                                             
      Glandular, Ulcer, Acute, Multifocal              1 (2%)                                                                       
      Glandular, Ulcer, Focal, Subacute                1 (2%)                                                                       
      Muscularis, Glandular, Mineralization,                                                                                        
          Multifocal                                   1 (2%)                                                                       
      Submucosa, Glandular, Inflammation,                                                                                           
          Multifocal, Subacute                         1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (2)          (50)                                                
      Artery, Mineralization, Multifocal               1 (2%)                                                                       
      Atrium Left, Thrombosis                                                    1 (2%)                                             
      Atrium Left, Thrombosis, Chronic                              1 (50%)                                                         
      Atrium Left, Thrombosis, Multiple, Subacute                                1 (2%)                                             
      Atrium Left, Thrombosis, Single                  2 (4%)                                                                       
      Myocardium, Degeneration, Chronic, Multifocal   46 (92%)      2 (100%)    44 (88%)                                            
      Myocardium, Degeneration, Multifocal             1 (2%)                    1 (2%)                                             
      Myocardium, Inflammation, Chronic, Multifocal    1 (2%)                                                                       
      Myocardium, Mineralization, Multifocal           1 (2%)                    1 (2%)                                             
      Ventricle Left, Thrombosis, Chronic, Focal       1 (2%)                                                                       
      Ventricle Left, Thrombosis, Multiple                                       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Gland                                      (50)         (3)          (50)                                                
      Bilateral, Cortex, Hematopoietic Cell                                                                                         
          Proliferation, Multifocal                                              1 (2%)                                             
      Bilateral, Cortex, Hyperplasia, Multifocal       3 (6%)                                                                       
      Bilateral, Cortex, Vacuolization Cytoplasmic,                                                                                 
           Multifocal                                  1 (2%)                    1 (2%)                                             
      Bilateral, Medulla, Hyperplasia, Multifocal      1 (2%)                                                                       
      Cortex, Congestion, Multifocal                                             1 (2%)                                             
      Cortex, Cytoplasmic Alteration, Focal            1 (2%)                    2 (4%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   12                                                              
NTP Experiment-Test: 05052-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         2,4-DICHLOROPHENOL                                    Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 20:09:14  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Cortex, Degeneration, Fatty, Focal               5 (10%)      1 (33%)      6 (12%)                                            
      Cortex, Degeneration, Fatty, Multifocal          5 (10%)                   1 (2%)                                             
      Cortex, Hematopoietic Cell Proliferation,                                                                                     
           Multifocal                                  1 (2%)                                                                       
      Cortex, Hyperplasia, Focal                       6 (12%)                   5 (10%)                                            
      Cortex, Hyperplasia, Multifocal                  1 (2%)                    1 (2%)                                             
      Cortex, Karyomegaly, Focal                                                 1 (2%)                                             
      Cortex, Necrosis, Multifocal                                               1 (2%)                                             
      Cortex, Nuclear Alteration, Focal                1 (2%)                                                                       
      Cortex, Vacuolization Cytoplasmic, Diffuse       1 (2%)                                                                       
      Cortex, Vacuolization Cytoplasmic, Multifocal    4 (8%)                                                                       
      Medulla, Cyst, Single                            1 (2%)                                                                       
      Medulla, Hyperplasia, Focal                      6 (12%)                  10 (20%)                                            
      Medulla, Hyperplasia, Multifocal                 6 (12%)                   3 (6%)                                             
   Islets, Pancreatic                                 (49)                      (49)                                                
      Hyperplasia, Focal                                                         1 (2%)                                             
   Parathyroid Gland                                  (42)         (1)          (44)                                                
      Cytoplasmic Alteration, Focal                    1 (2%)                                                                       
      Hyperplasia, Diffuse                             1 (2%)                                                                       
      Hyperplasia, Focal                               1 (2%)                                                                       
      Hyperplasia, Multifocal                          2 (5%)                    2 (5%)                                             
   Pituitary Gland                                    (49)         (44)         (49)                                                
      Pars Distalis, Cyst                              1 (2%)       4 (9%)                                                          
      Pars Distalis, Cyst, Multiple                                 1 (2%)       1 (2%)                                             
      Pars Distalis, Hemorrhage, Focal                                           1 (2%)                                             
      Pars Distalis, Hyperplasia, Focal                7 (14%)      7 (16%)      5 (10%)                                            
      Pars Distalis, Hyperplasia, Multifocal                                     5 (10%)                                            
      Pars Distalis, Karyomegaly, Multifocal                        1 (2%)                                                          
      Pars Intermedia, Cyst                            2 (4%)                                                                       
      Pars Intermedia, Cyst, Multiple                  2 (4%)                                                                       
      Pars Intermedia, Hemorrhage, Chronic, Focal                   1 (2%)                                                          
   Thyroid Gland                                      (49)         (49)         (50)                                                
      Bilateral, Follicle, Cyst, Multiple                           1 (2%)                                                          
      C-Cell, Hyperplasia, Focal                       6 (12%)      4 (8%)       6 (12%)                                            
      C-Cell, Hyperplasia, Multifocal                  5 (10%)      5 (10%)      3 (6%)                                             
      Follicle, Cyst                                   1 (2%)                    5 (10%)                                            
      Follicle, Cyst, Multiple                                                   1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   13                                                              
NTP Experiment-Test: 05052-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         2,4-DICHLOROPHENOL                                    Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 20:09:14  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Epididymis                                         (50)         (1)          (50)                                                
      Bilateral, Inflammation, Chronic, Multifocal                               1 (2%)                                             
      Bilateral, Inflammation, Multifocal, Subacute                              1 (2%)                                             
      Head, Granuloma Sperm, Single                                 1 (100%)                                                        
   Penis                                                                        (1)                                                 
      Inflammation, Acute, Multifocal, Necrotizing                               1 (100%)                                           
   Preputial Gland                                    (43)         (3)          (47)                                                
      Abscess                                          1 (2%)                                                                       
      Hyperplasia, Focal, Glandular                    1 (2%)                                                                       
      Hyperplasia, Glandular, Multifocal               1 (2%)                                                                       
      Hyperplasia, Multifocal, Nodular, Squamous                                 1 (2%)                                             
      Infiltration Cellular, Mononuclear Cell,                                                                                      
           Mononuclear Cell, Multifocal                1 (2%)                                                                       
      Inflammation, Chronic, Multifocal                1 (2%)                                                                       
      Inflammation, Chronic Active, Multifocal         4 (9%)                    3 (6%)                                             
      Inflammation, Chronic Active, Multifocal,                                                                                     
           Necrotizing                                                           1 (2%)                                             
      Inflammation, Multifocal, Subacute               2 (5%)                                                                       
      Bilateral, Hyperplasia, Glandular, Multifocal    1 (2%)                                                                       
      Bilateral, Inflammation, Chronic Active,                                                                                      
           Multifocal                                 27 (63%)                  36 (77%)                                            
      Bilateral, Duct, Ectasia, Focal                  1 (2%)                    1 (2%)                                             
      Bilateral, Duct, Ectasia, Multifocal             6 (14%)                   2 (4%)                                             
      Duct, Ectasia, Focal                                                       3 (6%)                                             
      Duct, Ectasia, Multifocal                        1 (2%)                    1 (2%)                                             
      Duct, Right, Ectasia, Diffuse                    1 (2%)                                                                       
   Prostate                                           (48)         (3)          (50)                                                
      Dilatation, Multifocal                                        1 (33%)                                                         
      Inflammation, Chronic, Multifocal                6 (13%)                   3 (6%)                                             
      Inflammation, Chronic, Multifocal,                                                                                            
          Suppurative                                  2 (4%)                                                                       
      Inflammation, Chronic Active, Multifocal                      2 (67%)      2 (4%)                                             
      Inflammation, Focal, Subacute                                              1 (2%)                                             
      Inflammation, Granulomatous, Multifocal          1 (2%)                                                                       
      Inflammation, Multifocal, Subacute               2 (4%)                    3 (6%)                                             
      Epithelium, Hyperplasia, Multifocal              1 (2%)                                                                       
      Serosa, Inflammation, Chronic, Multifocal                                  1 (2%)                                             
   Seminal Vesicle                                                 (1)                                                              
      Dilatation, Multifocal                                        1 (100%)                                                        
   Testes                                             (50)         (38)         (50)                                                
      Atrophy, Multifocal                                                        1 (2%)                                             
      Bilateral, Atrophy, Multifocal                   1 (2%)                                                                       
      Bilateral, Interstitial Cell, Hyperplasia,                                                                                    
           Multifocal                                  2 (4%)                    4 (8%)                                             
      Bilateral, Seminiferous Tubule, Atrophy,                                                                                      
           Chronic, Multifocal                                                   1 (2%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   14                                                              
NTP Experiment-Test: 05052-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         2,4-DICHLOROPHENOL                                    Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 20:09:14  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
      Bilateral, Seminiferous Tubule, Atrophy,                                                                                      
           Multifocal                                 27 (54%)     20 (53%)     20 (40%)                                            
      Interstitial Cell, Hyperplasia, Multifocal                    4 (11%)      2 (4%)                                             
      Interstitial Cell, Right, Hyperplasia,                                                                                        
          Multifocal                                   8 (16%)      3 (8%)       3 (6%)                                             
      Interstitial Cell, Left, Hyperplasia, Focal                                1 (2%)                                             
      Interstitial Cell, Left, Hyperplasia,                                                                                         
          Multifocal                                   5 (10%)      4 (11%)      2 (4%)                                             
      Interstitial Tissue, Hemorrhage, Chronic                                                                                      
          Active, Multifocal                                        1 (3%)                                                          
      Interstitial Tissue, Right, Hemorrhage,                                                                                       
          Chronic Active, Multifocal                                1 (3%)                                                          
      Left, Atrophy, Multifocal                                     1 (3%)                                                          
      Seminiferous Tubule, Atrophy, Multifocal         4 (8%)       4 (11%)      3 (6%)                                             
      Seminiferous Tubule, Right, Atrophy,                                                                                          
          Multifocal                                   5 (10%)      4 (11%)      3 (6%)                                             
      Seminiferous Tubule, Left, Atrophy,                                                                                           
          Multifocal                                   6 (12%)      3 (8%)       4 (8%)                                             
      Vein, Ectasia, Chronic, Multifocal                            1 (3%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Blood                                              (26)                      (16)                                                
      Neutrophilia                                     2 (8%)                                                                       
   Bone Marrow                                        (49)                      (50)                                                
      Hyperplasia, Multifocal, Neutrophil              4 (8%)                    1 (2%)                                             
      Myelofibrosis, Multifocal                        1 (2%)                                                                       
      Myeloid Cell, Erythroid Cell, Hypoplasia,                                                                                     
           Diffuse                                                               1 (2%)                                             
      Myeloid Cell, Erythroid Cell, Hypoplasia,                                                                                     
           Multifocal                                  2 (4%)                                                                       
   Lymph Node                                         (50)         (9)          (50)                                                
      Depletion Lymphoid, Multifocal                                             1 (2%)                                             
      Hyperplasia, Lymphoid, Multifocal                1 (2%)                                                                       
      Inguinal, Inflammation, Granulomatous,                                                                                        
          Multifocal                                                1 (11%)                                                         
      Lumbar, Inflammation, Granulomatous,                                                                                          
          Multifocal                                                1 (11%)                                                         
      Mandibular, Cyst                                 3 (6%)                    1 (2%)                                             
      Mandibular, Depletion Lymphoid, Multifocal                                 1 (2%)                                             
      Mandibular, Hemorrhage, Multifocal               3 (6%)                    5 (10%)                                            
      Mandibular, Hyperplasia, Lymphoid, Multifocal    6 (12%)                   5 (10%)                                            
      Mandibular, Hyperplasia, Multifocal, Plasma                                                                                   
          Cell                                                                   5 (10%)                                            
      Mandibular, Infiltration Cellular,                                                                                            
          Multifocal, Plasma Cell                      1 (2%)                    1 (2%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   15                                                              
NTP Experiment-Test: 05052-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         2,4-DICHLOROPHENOL                                    Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 20:09:14  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Mandibular, Inflammation, Chronic, Multifocal    1 (2%)                    1 (2%)                                             
      Mandibular, Inflammation, Granulomatous,                                                                                      
           Multifocal                                                            1 (2%)                                             
      Mediastinal, Hemorrhage, Multifocal              3 (6%)                    4 (8%)                                             
      Mediastinal, Hyperplasia, Lymphoid,                                                                                           
          Multifocal                                   1 (2%)                                                                       
      Mediastinal, Inflammation, Chronic,                                                                                           
          Multifocal                                                1 (11%)                                                         
      Mediastinal, Inflammation, Chronic Active,                                                                                    
           Multifocal                                               1 (11%)                                                         
      Mediastinal, Inflammation, Granulomatous,                                                                                     
           Multifocal                                  1 (2%)                    3 (6%)                                             
      Mediastinal, Inflammation, Multifocal,                                                                                        
          Subacute                                     1 (2%)                                                                       
      Mediastinal, Pigmentation, Hemosiderin,                                                                                       
          Multifocal                                                1 (11%)                                                         
      Mesenteric, Cyst                                 1 (2%)                                                                       
      Mesenteric, Cyst, Multiple                       1 (2%)                    1 (2%)                                             
      Mesenteric, Hemorrhage, Multifocal               1 (2%)       1 (11%)                                                         
      Mesenteric, Hyperplasia, Lymphoid, Multifocal    1 (2%)                                                                       
      Mesenteric, Inflammation, Chronic, Multifocal    1 (2%)                                                                       
      Mesenteric, Inflammation, Granulomatous,                                                                                      
           Multifocal                                  1 (2%)       1 (11%)                                                         
      Pancreatic, Cyst                                 1 (2%)                                                                       
      Pancreatic, Hemorrhage, Multifocal               2 (4%)                                                                       
   Spleen                                             (50)         (14)         (50)                                                
      Necrosis, Diffuse, Subacute                      1 (2%)                                                                       
      Capsule, Cyst, Multiple                                       1 (7%)                                                          
      Lymphoid Follicle, Necrosis, Acute,                                                                                           
          Multifocal                                                             1 (2%)                                             
      Red Pulp, Fibrosis, Chronic, Focal                            1 (7%)                                                          
      Red Pulp, Fibrosis, Chronic, Multifocal          1 (2%)       1 (7%)                                                          
      Red Pulp, Fibrosis, Focal                        2 (4%)       1 (7%)                                                          
      Red Pulp, Fibrosis, Multifocal                   3 (6%)       1 (7%)       1 (2%)                                             
      Red Pulp, Hematopoietic Cell Proliferation,                                                                                   
           Multifocal                                  2 (4%)                    5 (10%)                                            
      Red Pulp, Pigmentation, Hemosiderin,                                                                                          
          Multifocal                                   1 (2%)                    2 (4%)                                             
   Thymus                                             (39)         (1)          (43)                                                
      Depletion Lymphoid, Multifocal                  30 (77%)                  33 (77%)                                            
      Artery, Mediastinum, Inflammation, Chronic,                                                                                   
           Multifocal, Proliferative                   1 (3%)                                                                       
      Epithelial Cell, Hyperplasia, Multifocal                      1 (100%)                                                        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   16                                                              
NTP Experiment-Test: 05052-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         2,4-DICHLOROPHENOL                                    Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 20:09:14  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (25)         (4)          (22)                                                
      Acinus, Hyperplasia, Cystic, Multifocal         19 (76%)                  12 (55%)                                            
      Acinus, Hyperplasia, Multifocal                  1 (4%)                    2 (9%)                                             
   Skin                                               (49)         (12)         (50)                                                
      Abdominal, Inflammation, Chronic, Focal,                                                                                      
           Suppurative                                                           1 (2%)                                             
      Abdominal, Subcutaneous Tissue, Edema,                                                                                        
          Multifocal, Subacute                                                   1 (2%)                                             
      Inguinal, Abscess                                                          1 (2%)                                             
      Inguinal, Ulcer, Chronic Active, Focal           1 (2%)                                                                       
      Inguinal, Subcutaneous Tissue, Inflammation,                                                                                  
           Chronic Active, Multifocal                                            1 (2%)                                             
      Tail, Hyperkeratosis, Multifocal                 1 (2%)                                                                       
      Thoracic, Subcutaneous Tissue, Hemorrhage,                                                                                    
           Chronic Active, Diffuse                                  1 (8%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (49)                      (48)                                                
      Femur, Osteopetrosis, Multifocal                 3 (6%)                    1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (1)          (50)                                                
      Cerebellum, Hemorrhage, Acute, Multifocal        1 (2%)                                                                       
      Cerebellum, Cerebrum, Hemorrhage, Multifocal                  1 (100%)                                                        
      Cerebrum, Hemorrhage, Acute, Multifocal          1 (2%)                                                                       
      Cerebrum, Hemorrhage, Focal                      1 (2%)                                                                       
      Medulla, Cerebrum, Hemorrhage, Acute,                                                                                         
          Multifocal                                                             1 (2%)                                             
      Third Ventricle, Hemorrhage, Focal                                         1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (3)          (50)                                                
      Congestion, Acute, Diffuse                                                 1 (2%)                                             
      Inflammation, Granulomatous, Multifocal          1 (2%)                    1 (2%)                                             
      Alveolar Epithelium, Hyperplasia, Multifocal     2 (4%)                                                                       
      Bronchiole, Epithelium, Hyperplasia,                                                                                          
          Multifocal                                   1 (2%)                                                                       
      Interstitium, Inflammation, Acute, Focal                                   2 (4%)                                             
      Interstitium, Inflammation, Chronic, Focal                    1 (33%)                                                         
      Interstitium, Inflammation, Chronic,                                                                                          
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   17                                                              
NTP Experiment-Test: 05052-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         2,4-DICHLOROPHENOL                                    Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 20:09:14  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - CONT                                                                                                           
          Multifocal                                   6 (12%)                   1 (2%)                                             
      Interstitium, Inflammation, Multifocal,                                                                                       
          Subacute                                                               1 (2%)                                             
      Interstitium, Metaplasia, Focal, Osseous         1 (2%)                                                                       
      Interstitium, Mineralization, Multifocal         1 (2%)       1 (33%)                                                         
      Mediastinum, Inflammation, Granulomatous,                                                                                     
           Multifocal                                                            1 (2%)                                             
   Nose                                               (45)         (48)         (46)                                                
      Degeneration, Multifocal                                                   1 (2%)                                             
      Nasolacrimal Duct, Inflammation, Chronic,                                                                                     
           Multifocal                                  1 (2%)                                                                       
      Nasolacrimal Duct, Inflammation, Focal,                                                                                       
          Subacute                                     4 (9%)       1 (2%)       6 (13%)                                            
      Nasolacrimal Duct, Inflammation, Multifocal      1 (2%)                                                                       
      Nasolacrimal Duct, Inflammation, Multifocal,                                                                                  
           Subacute                                   20 (44%)     19 (40%)     11 (24%)                                            
      Respiratory Epithelium, Degeneration,                                                                                         
          Multifocal                                  25 (56%)     38 (79%)     42 (91%)                                            
      Respiratory Epithelium, Inflammation,                                                                                         
          Chronic, Focal                               1 (2%)                                                                       
      Respiratory Epithelium, Inflammation,                                                                                         
          Multifocal, Subacute                         2 (4%)                                                                       
      Respiratory Epithelium, Metaplasia,                                                                                           
          Multifocal, Squamous                         2 (4%)                                                                       
      Submucosa, Olfactory Epithelium,                                                                                              
          Inflammation, Multifocal, Subacute           1 (2%)                                                                       
      Submucosa, Respiratory Epithelium,                                                                                            
          Concretion, Multifocal                                    1 (2%)                                                          
      Submucosa, Respiratory Epithelium,                                                                                            
          Inflammation, Acute, Focal                                             1 (2%)                                             
      Submucosa, Respiratory Epithelium,                                                                                            
          Inflammation, Acute, Multifocal              1 (2%)       3 (6%)       1 (2%)                                             
      Submucosa, Respiratory Epithelium,                                                                                            
          Inflammation, Chronic, Multifocal            4 (9%)                                                                       
      Submucosa, Respiratory Epithelium,                                                                                            
          Inflammation, Chronic, Multifocal,                                                                                        
          Suppurative                                                            1 (2%)                                             
      Submucosa, Respiratory Epithelium,                                                                                            
          Inflammation, Focal, Subacute                             2 (4%)       1 (2%)                                             
      Submucosa, Respiratory Epithelium,                                                                                            
          Inflammation, Multifocal                     1 (2%)                                                                       
      Submucosa, Respiratory Epithelium,                                                                                            
          Inflammation, Multifocal, Subacute          19 (42%)     23 (48%)     22 (48%)                                            
      Submucosa, Respiratory Epithelium,                                                                                            
          Inflammation, Multifocal, Suppurative        2 (4%)                    1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   18                                                              
NTP Experiment-Test: 05052-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         2,4-DICHLOROPHENOL                                    Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 20:09:14  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (4)          (4)          (2)                                                 
      Cornea, Inflammation, Multifocal, Subacute       1 (25%)                                                                      
      Lens, Cataract                                                             1 (50%)                                            
      Lens, Cataract, Multifocal                       2 (50%)      2 (50%)                                                         
      Retina, Atrophy, Multifocal                      3 (75%)      2 (50%)      1 (50%)                                            
   Harderian Gland                                    (43)                      (36)                                                
      Hyperplasia, Focal, Glandular                                              1 (3%)                                             
      Hyperplasia, Glandular, Multifocal               1 (2%)                                                                       
      Inflammation, Granulomatous, Multifocal                                    1 (3%)                                             
      Inflammation, Multifocal, Subacute                                         3 (8%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (8)          (49)                                                
      Congestion, Multifocal                                        1 (13%)                                                         
      Cyst                                                          1 (13%)                                                         
      Cyst, Multiple                                   1 (2%)                                                                       
      Polycystic Kidney                                             1 (13%)                                                         
      Bilateral, Nephropathy, Chronic, Multifocal     49 (98%)      6 (75%)     48 (98%)                                            
      Bilateral, Cortex, Cyst, Multiple                             1 (13%)                                                         
      Bilateral, Cortex, Mineralization, Multifocal                 1 (13%)                                                         
      Bilateral, Pelvis, Hydronephrosis, Multifocal                 1 (13%)                                                         
      Cortex, Cyst                                     3 (6%)       1 (13%)                                                         
      Cortex, Cyst, Multiple                           2 (4%)                                                                       
      Cortex, Cyst, Single                             4 (8%)                                                                       
      Left, Nephropathy, Chronic, Multifocal           1 (2%)                                                                       
      Papilla, Epithelium, Hyperplasia, Multifocal     1 (2%)                                                                       
      Renal Tubule, Pigmentation, Multifocal           1 (2%)                                                                       
      Right, Cyst                                                   1 (13%)                                                         
   Urinary Bladder                                    (48)         (2)          (50)                                                
      Inflammation, Acute, Hemorrhagic, Multifocal                  1 (50%)                                                         
      Mucosa, Hyperplasia, Multifocal                  1 (2%)       1 (50%)      1 (2%)                                             
      Muscularis, Inflammation, Chronic Active,                                                                                     
           Multifocal                                               1 (50%)                                                         
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   19                                                              
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NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.