National Toxicology Program

National Toxicology Program
https://ntp.niehs.nih.gov/go/2653

TDMS Study 05052-02 Pathology Tables


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


NTP Experiment-Test: 05052-02                                                                                     Report: PEIRPT03
Study Type: CHRONIC                                                                                               Date: 09/07/94
Route: DOSED FEED                                                                                                 Time: 23:47:53




       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: 05052-02         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: 23:47:53  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially In Study                          50           50           50                                                  
  Early Deaths                                                                                                                      
    Dead                                               4           10            5                                                  
    Moribund                                           1                         2                                                  
  Survivors                                                                                                                         
    Terminal Sacrifice                                45           40           43                                                  
  Animals Examined Microscopically                    50           50           50                                                  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Gallbladder                                        (46)                      (45)                                                
      Mucosa, Cyst                                     1 (2%)                                                                       
   Intestine Small                                    (48)         (2)          (47)                                                
      Ileum, Peyer's Patch, Inflammation, Acute,                                                                                    
           Focal                                       1 (2%)                                                                       
      Jejunum, Peyer's Patch, Hyperplasia, Diffuse,                                                                                 
           Lymphoid                                                 1 (50%)                                                         
      Jejunum, Peyer's Patch, Hyperplasia,                                                                                          
          Lymphoid, Multifocal                         1 (2%)                                                                       
   Liver                                              (50)         (6)          (50)                                                
      Basophilic Focus, Multiple                       1 (2%)                                                                       
      Basophilic Focus, Single                         2 (4%)                    2 (4%)                                             
      Clear Cell Focus                                                           1 (2%)                                             
      Eosinophilic Focus, Single                                    1 (17%)                                                         
      Hematopoietic Cell Proliferation, Multifocal     1 (2%)                                                                       
      Infiltration Cellular, Multifocal, Lymphocyte    1 (2%)                                                                       
      Inflammation, Granulomatous, Multifocal                                    1 (2%)                                             
      Inflammation, Multifocal, Subacute               1 (2%)                                                                       
      Hepatocyte, Hyperplasia, Focal                   1 (2%)                                                                       
      Hepatocyte, Inflammation, Acute, Focal           2 (4%)                                                                       
      Hepatocyte, Inflammation, Multifocal,                                                                                         
          Necrotizing, Subacute                        1 (2%)                                                                       
      Hepatocyte, Necrosis, Acute, Diffuse                                       1 (2%)                                             
      Hepatocyte, Necrosis, Acute, Multifocal                       1 (17%)      2 (4%)                                             
      Hepatocyte, Nuclear Alteration, Focal                                      1 (2%)                                             
      Hepatocyte, Vacuolization Cytoplasmic, Focal     1 (2%)       1 (17%)                                                         
      Kupffer Cell, Pigmentation, Multifocal           1 (2%)                                                                       
      Left Lateral Lobe, Angiectasis, Focal            1 (2%)                                                                       
   Mesentery                                          (47)         (1)          (48)                                                
      Inflammation, Acute, Multifocal                                            1 (2%)                                             
      Inflammation, Multifocal, Subacute               1 (2%)                                                                       
      Thrombosis                                       1 (2%)                                                                       
      Fat, Necrosis, Chronic, Focal                                 1 (100%)                                                        
      Fat, Necrosis, Focal                             1 (2%)                                                                       
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    2                                                              
NTP Experiment-Test: 05052-02         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: 23:47:53  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
   Pancreas                                           (49)                      (47)                                                
      Cyst, Multifocal                                 1 (2%)                                                                       
      Infiltration Cellular, Multifocal, Lymphocyte                              1 (2%)                                             
      Acinus, Atrophy, Diffuse                         1 (2%)                    1 (2%)                                             
      Acinus, Atrophy, Focal                           1 (2%)                    1 (2%)                                             
      Acinus, Atrophy, Multifocal                      1 (2%)                    2 (4%)                                             
   Pharynx                                                         (1)                                                              
      Palate, Epithelium, Hyperplasia                               1 (100%)                                                        
   Salivary Glands                                    (49)                      (47)                                                
      Infiltration Cellular, Focal, Lymphocyte                                   1 (2%)                                             
      Infiltration Cellular, Multifocal, Lymphocyte                              1 (2%)                                             
   Stomach                                            (49)         (14)         (48)                                                
      Forestomach, Erosion, Focal                      1 (2%)                                                                       
      Forestomach, Epithelium, Hyperplasia, Focal     10 (20%)     10 (71%)      4 (8%)                                             
      Mucosa, Glandular, Mineralization, Diffuse       1 (2%)                                                                       
   Tooth                                              (48)                      (44)                                                
      Peridontal Tissue, Inflammation, Acute, Focal    1 (2%)                    1 (2%)                                             
      Peridontal Tissue, Inflammation, Focal,                                                                                       
          Granulomatous                                1 (2%)                                                                       
      Peridontal Tissue, Inflammation, Focal,                                                                                       
          Necrotizing                                  1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (1)          (50)                                                
      Myocardium, Mineralization, Multifocal           1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Gland                                      (49)         (1)          (50)                                                
      Cortex, Focal Cellular Change                    3 (6%)                                                                       
      Cortex, Hyperplasia, Focal                       2 (4%)                                                                       
      Medulla, Hyperplasia, Focal                      2 (4%)                                                                       
      Medulla, Hypertrophy                             1 (2%)                                                                       
      Spindle Cell, Hyperplasia, Diffuse              45 (92%)                  47 (94%)                                            
      Spindle Cell, Hyperplasia, Multifocal            1 (2%)                    1 (2%)                                             
      Subcapsular, Cyst                                1 (2%)                                                                       
   Parathyroid Gland                                  (39)                      (38)                                                
      Cyst                                             1 (3%)                                                                       
      Hyperplasia, Focal                               1 (3%)                                                                       
   Pituitary Gland                                    (49)                      (48)                                                
      Pars Distalis, Angiectasis, Focal                1 (2%)                    1 (2%)                                             
      Pars Distalis, Cyst                                                        1 (2%)                                             
      Pars Distalis, Hyperplasia, Focal                3 (6%)                    3 (6%)                                             
      Pars Distalis, Hyperplasia, Multifocal           3 (6%)                    1 (2%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    3                                                              
NTP Experiment-Test: 05052-02         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: 23:47:53  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Pars Intermedia, Hyperplasia, Focal              2 (4%)                                                                       
   Thyroid Gland                                      (49)                      (47)                                                
      Ectopic Tissue                                   1 (2%)                                                                       
      Follicle, Cyst                                                             2 (4%)                                             
      Follicle, Cyst, Multiple                         1 (2%)                    1 (2%)                                             
      Follicle, Inflammation, Focal, Granulomatous                               1 (2%)                                             
      Follicle, Inflammation, Multifocal, Subacute                               1 (2%)                                             
      Follicular Cell, Hyperplasia, Cystic, Focal                                1 (2%)                                             
      Follicular Cell, Hyperplasia, Multifocal         1 (2%)                    3 (6%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Ovary                                              (48)         (22)         (48)                                                
      Angiectasis, Diffuse                             1 (2%)                                                                       
      Cyst                                             1 (2%)                                                                       
      Hyperplasia, Focal                                                         1 (2%)                                             
      Bilateral, Abscess, Chronic Active,                                                                                           
          Multifocal                                   1 (2%)       1 (5%)                                                          
      Bilateral, Periovarian Tissue, Cyst              1 (2%)       2 (9%)       2 (4%)                                             
      Follicle, Cyst                                   2 (4%)       2 (9%)       5 (10%)                                            
      Left, Abscess, Chronic, Focal                                 2 (9%)                                                          
      Left, Follicle, Cyst                             2 (4%)       1 (5%)       1 (2%)                                             
      Periovarian Tissue, Cyst                         1 (2%)       3 (14%)      5 (10%)                                            
      Periovarian Tissue, Right, Cyst                  4 (8%)       6 (27%)      2 (4%)                                             
      Periovarian Tissue, Left, Cyst                   3 (6%)       4 (18%)      3 (6%)                                             
      Right, Abscess, Chronic Active, Single                        1 (5%)                                                          
      Right, Follicle, Cyst                            1 (2%)       1 (5%)                                                          
   Uterus                                             (49)         (40)         (49)                                                
      Hyperplasia, Cystic, Diffuse, Glandular                                    1 (2%)                                             
      Endometrium, Angiectasis                                                   1 (2%)                                             
      Endometrium, Angiectasis, Focal                  1 (2%)                                                                       
      Endometrium, Hyperplasia, Cystic, Diffuse,                                                                                    
           Glandular                                  48 (98%)     38 (95%)     44 (90%)                                            
      Endometrium, Inflammation, Focal, Suppurative                 1 (3%)                                                          
      Endometrium, Metaplasia, Squamous                1 (2%)                    1 (2%)                                             
      Lumen, Dilatation                                3 (6%)                    1 (2%)                                             
      Lumen, Dilatation, Diffuse                       1 (2%)                    1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    4                                                              
NTP Experiment-Test: 05052-02         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: 23:47:53  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)                      (50)                                                
      Femoral, Hyperplasia, Diffuse, Neutrophil                                  1 (2%)                                             
   Lymph Node                                         (48)         (9)          (46)                                                
      Bronchial, Hyperplasia, Diffuse, Lymphoid        1 (2%)                                                                       
      Lumbar, Hyperplasia, Diffuse, Lymphoid                        1 (11%)                                                         
      Lumbar, Sinus, Ectasia, Focal                    1 (2%)                                                                       
      Mandibular, Hyperplasia, Diffuse, Lymphoid                                 1 (2%)                                             
      Mediastinal, Hyperplasia, Diffuse, Lymphoid                                1 (2%)                                             
      Mediastinal, Pigmentation, Diffuse               1 (2%)                                                                       
      Mesenteric, Angiectasis, Diffuse                 5 (10%)                                                                      
      Mesenteric, Angiectasis, Multifocal                           1 (11%)                                                         
      Mesenteric, Hyperplasia, Diffuse, Lymphoid                    1 (11%)                                                         
      Renal, Hyperplasia, Diffuse, Lymphoid                         1 (11%)      1 (2%)                                             
   Spleen                                             (49)         (9)          (49)                                                
      Inflammation, Chronic                                         1 (11%)                                                         
      Capsule, Inflammation, Acute, Diffuse                                      1 (2%)                                             
      Lymphoid Follicle, Depletion Lymphoid,                                                                                        
          Diffuse                                      2 (4%)                    1 (2%)                                             
      Lymphoid Follicle, Hyperplasia, Diffuse,                                                                                      
           Lymphoid                                    2 (4%)       1 (11%)      4 (8%)                                             
      Lymphoid Follicle, Hyperplasia, Lymphoid         1 (2%)                                                                       
      Lymphoid Follicle, Hyperplasia, Lymphoid,                                                                                     
           Multifocal                                  1 (2%)                    1 (2%)                                             
      Red Pulp, Angiectasis, Multifocal                1 (2%)                                                                       
      Red Pulp, Hematopoietic Cell Proliferation,                                                                                   
           Diffuse                                     4 (8%)       2 (22%)      2 (4%)                                             
   Thymus                                             (47)         (1)          (42)                                                
      Atrophy, Diffuse                                 1 (2%)                                                                       
      Depletion Lymphoid, Diffuse                      2 (4%)                    1 (2%)                                             
      Medulla, Hyperplasia, Diffuse, Lymphoid                                    2 (5%)                                             
      Thymocyte, Necrosis, Acute, Diffuse                                        1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Skin                                               (48)         (1)          (49)                                                
      Face, Subcutaneous Tissue, Inflammation,                                                                                      
           Focal, Granulomatous                        1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (2)          (50)                                                
      Cranium, Myelofibrosis                                                     2 (4%)                                             
      Cranium, Myelofibrosis, Focal                                              1 (2%)                                             
      Cranium, Myelofibrosis, Multifocal               1 (2%)                    1 (2%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    5                                                              
NTP Experiment-Test: 05052-02         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: 23:47:53  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
MUSCULOSKELETAL SYSTEM - CONT                                                                                                       
      Cranium, Femur, Myelofibrosis, Diffuse                                     2 (4%)                                             
      Cranium, Femur, Myelofibrosis, Multifocal                                  7 (14%)                                            
      Femur, Myelofibrosis, Diffuse                    2 (4%)                    1 (2%)                                             
      Femur, Myelofibrosis, Focal                      4 (8%)                    5 (10%)                                            
      Femur, Myelofibrosis, Multifocal                19 (38%)                  12 (24%)                                            
      Vertebra, Myelofibrosis, Multifocal                           1 (50%)                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)                      (48)                                                
      Compression, Focal                               1 (2%)                    1 (2%)                                             
      Meninges, Infiltration Cellular, Multifocal,                                                                                  
           Lymphocyte                                  3 (6%)                    1 (2%)                                             
      Thalamus, Mineralization                         4 (8%)                    3 (6%)                                             
      Third Ventricle, Infiltration Cellular,                                                                                       
          Multifocal, Lymphocyte                                                 1 (2%)                                             
   Spinal Cord                                                     (1)                                                              
      Thoracic, Hemorrhage, Acute, Focal                            1 (100%)                                                        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (1)          (50)                                                
      Infiltration Cellular, Multifocal, Lymphocyte    1 (2%)                    1 (2%)                                             
      Inflammation, Focal, Granulomatous               1 (2%)                                                                       
      Inflammation, Focal, Subacute                    1 (2%)                                                                       
      Alveolar Epithelium, Hyperplasia, Focal          3 (6%)                    3 (6%)                                             
      Interstitium, Inflammation, Focal, Subacute                                1 (2%)                                             
      Mediastinum, Infiltration Cellular,                                                                                           
          Multifocal, Lymphocyte                       1 (2%)                                                                       
      Vein, Intima, Mineralization, Focal              1 (2%)                                                                       
   Nose                                               (48)                      (44)                                                
      Mucosa, Inflammation, Acute, Multifocal          1 (2%)                                                                       
      Submucosa, Glands, Ectasia, Multifocal           1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (1)                                                                           
      Developmental Malformation                       1 (100%)                                                                     
   Harderian Gland                                    (35)         (2)          (41)                                                
      Hyperplasia, Focal                               1 (3%)                    1 (2%)                                             
      Infiltration Cellular, Multifocal, Lymphocyte                              1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    6                                                              
NTP Experiment-Test: 05052-02         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: 23:47:53  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (49)                      (50)                                                
      Infiltration Cellular, Multifocal, Lymphocyte                              4 (8%)                                             
      Capsule, Inflammation, Diffuse, Subacute                                   1 (2%)                                             
      Capsule, Inflammation, Multifocal, Subacute      1 (2%)                                                                       
      Cortex, Infarct, Chronic                         1 (2%)                                                                       
      Cortex, Metaplasia, Focal, Osseous               1 (2%)                                                                       
      Glomerulus, Inflammation, Diffuse, Subacute,                                                                                  
           Membranoproliferative                                                 1 (2%)                                             
      Glomerulus, Inflammation, Diffuse,                                                                                            
          Proliferative                                1 (2%)                                                                       
      Interstitial Tissue, Inflammation, Multifocal                              1 (2%)                                             
      Renal Tubule, Casts Protein, Diffuse             1 (2%)                                                                       
      Renal Tubule, Cytoplasmic Alteration, Diffuse    1 (2%)                                                                       
      Renal Tubule, Cytoplasmic Alteration,                                                                                         
          Multifocal                                   1 (2%)                                                                       
      Renal Tubule, Degeneration                       1 (2%)                                                                       
      Renal Tubule, Degeneration, Diffuse              1 (2%)                                                                       
      Renal Tubule, Inflammation, Multifocal,                                                                                       
          Necrotizing, Subacute                                                  1 (2%)                                             
      Renal Tubule, Necrosis, Acute, Multifocal                                  1 (2%)                                             
      Renal Tubule, Pigmentation, Diffuse                                        1 (2%)                                             
      Renal Tubule, Regeneration, Focal                3 (6%)                                                                       
      Renal Tubule, Regeneration, Multifocal           2 (4%)                    7 (14%)                                            
   Urinary Bladder                                    (48)                      (47)                                                
      Serosa, Inflammation, Acute, Multifocal                                    1 (2%)                                             
      Submucosa, Infiltration Cellular, Multifocal,                                                                                 
           Lymphocyte                                                            2 (4%)                                             
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    7                                                              
NTP Experiment-Test: 05052-02         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: 23:47:53  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially In Study                          50           50           50                                                  
  Early Deaths                                                                                                                      
    Dead                                              12           14           12                                                  
    Moribund                                           5            4            3                                                  
    Drowned                                                                      4                                                  
  Survivors                                                                                                                         
    Terminal Sacrifice                                33           32           31                                                  
  Animals Examined Microscopically                    50           50           50                                                  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large                                    (48)         (1)          (45)                                                
      Colon, Parasite Metazoan, Single                 1 (2%)                    1 (2%)                                             
   Intestine Small                                    (44)         (1)          (41)                                                
      Thrombosis, Acute, Multifocal                    1 (2%)                                                                       
      Jejunum, Peyer's Patch, Hyperplasia,                                                                                          
          Lymphoid, Multifocal                         1 (2%)                                                                       
   Liver                                              (50)         (49)         (48)                                                
      Basophilic Focus, Multiple                       1 (2%)                    1 (2%)                                             
      Basophilic Focus, Single                         2 (4%)       1 (2%)       2 (4%)                                             
      Inflammation, Granulomatous, Multifocal          1 (2%)                                                                       
      Inflammation, Multifocal, Subacute                            1 (2%)       1 (2%)                                             
      Bile Duct, Hyperplasia, Multifocal               1 (2%)                                                                       
      Caudate Lobe, Necrosis, Chronic Active, Focal                 1 (2%)                                                          
      Hepatocyte, Cytomegaly                                        1 (2%)                                                          
      Hepatocyte, Cytomegaly, Diffuse                               1 (2%)                                                          
      Hepatocyte, Cytomegaly, Multifocal                            1 (2%)                                                          
      Hepatocyte, Necrosis, Acute, Diffuse                                       3 (6%)                                             
      Hepatocyte, Necrosis, Acute, Focal                                         1 (2%)                                             
      Hepatocyte, Necrosis, Acute, Multifocal          2 (4%)       6 (12%)                                                         
      Hepatocyte, Necrosis, Coagulative,                                                                                            
          Multifocal, Subacute                         1 (2%)                                                                       
      Hepatocyte, Nuclear Alteration, Diffuse          2 (4%)                                                                       
      Hepatocyte, Nuclear Alteration, Focal           15 (30%)     27 (55%)     18 (38%)                                            
      Hepatocyte, Nuclear Alteration, Multifocal       2 (4%)       3 (6%)                                                          
      Hepatocyte, Syncytial Alteration, Diffuse       11 (22%)     33 (67%)     42 (88%)                                            
      Hepatocyte, Vacuolization Cytoplasmic, Focal                               1 (2%)                                             
      Sinusoid, Infiltration Cellular, Diffuse,                                                                                     
           Polymorphonuclear                                        1 (2%)                                                          
   Mesentery                                          (21)         (1)          (37)                                                
      Fat, Necrosis, Acute, Diffuse                                              1 (3%)                                             
      Fat, Necrosis, Multifocal                                     1 (100%)                                                        
   Pancreas                                           (49)                      (45)                                                
      Acinus, Atrophy, Focal                                                     2 (4%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    8                                                              
NTP Experiment-Test: 05052-02         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: 23:47:53  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
   Salivary Glands                                    (50)                      (49)                                                
      Periductular, Infiltration Cellular,                                                                                          
          Multifocal, Lymphocyte                                                 1 (2%)                                             
   Stomach                                            (48)         (6)          (46)                                                
      Forestomach, Epithelium, Hyperplasia, Focal      5 (10%)      6 (100%)     4 (9%)                                             
      Glandular, Dysplasia, Focal                      1 (2%)                                                                       
      Glandular, Inflammation, Acute, Focal                                      1 (2%)                                             
   Tooth                                              (40)                      (34)                                                
      Peridontal Tissue, Inflammation, Acute, Focal    2 (5%)                    1 (3%)                                             
      Peridontal Tissue, Inflammation, Acute,                                                                                       
          Multifocal                                   2 (5%)                    1 (3%)                                             
      Peridontal Tissue, Inflammation, Chronic                                                                                      
          Active, Focal                                6 (15%)                                                                      
      Peridontal Tissue, Inflammation, Chronic                                                                                      
          Active, Multifocal                           1 (3%)                    2 (6%)                                             
      Peridontal Tissue, Inflammation, Focal,                                                                                       
          Subacute                                                               1 (3%)                                             
      Pulp, Inflammation, Acute, Focal                 3 (8%)                                                                       
      Pulp, Inflammation, Acute, Focal, Necrotizing                              1 (3%)                                             
      Pulp, Necrosis, Acute, Diffuse                                             1 (3%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (1)          (50)                                                
      Myocardium, Inflammation, Acute, Focal,                                                                                       
          Suppurative                                                            1 (2%)                                             
      Myocardium, Inflammation, Acute, Multifocal                                1 (2%)                                             
      Myocardium, Inflammation, Chronic, Focal         1 (2%)                                                                       
      Myocardium, Inflammation, Multifocal,                                                                                         
          Subacute                                                               1 (2%)                                             
      Ventricle Right, Necrosis, Chronic, Focal                                  1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Gland                                      (49)                      (45)                                                
      Accessory Adrenal Cortical Nodule                                          1 (2%)                                             
      Accessory Adrenal Cortical Nodule, Focal                                   1 (2%)                                             
      Cortex, Degeneration, Fatty, Focal               1 (2%)                                                                       
      Cortex, Focal Cellular Change                    4 (8%)                    4 (9%)                                             
      Cortex, Focal Cellular Change, Multifocal        1 (2%)                    2 (4%)                                             
      Cortex, Hyperplasia, Focal                       3 (6%)                    1 (2%)                                             
      Cortex, Hypertrophy                                                        3 (7%)                                             
      Medulla, Hyperplasia, Focal                      1 (2%)                    1 (2%)                                             
      Spindle Cell, Hyperplasia, Focal                                           1 (2%)                                             
      Spindle Cell, Hyperplasia, Multifocal            7 (14%)                   5 (11%)                                            
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    9                                                              
NTP Experiment-Test: 05052-02         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: 23:47:53  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
   Parathyroid Gland                                  (38)                      (35)                                                
      Infiltration Cellular, Focal, Lymphocyte         1 (3%)                                                                       
   Pituitary Gland                                    (45)                      (47)                                                
      Pars Distalis, Inflammation, Acute, Focal                                  1 (2%)                                             
   Thyroid Gland                                      (50)                      (48)                                                
      Follicle, Cyst, Multiple                                                   2 (4%)                                             
      Follicle, Cyst, Single                           5 (10%)                   2 (4%)                                             
      Follicular Cell, Hyperplasia, Focal              1 (2%)                                                                       
      Follicular Cell, Hyperplasia, Multifocal         2 (4%)                    1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Coagulating Gland                                  (4)                       (20)                                                
      Wall, Inflammation, Acute, Multifocal            1 (25%)                                                                      
   Epididymis                                         (48)                      (48)                                                
      Granuloma Sperm, Focal                           1 (2%)                                                                       
      Inflammation, Chronic, Focal                     1 (2%)                                                                       
      Epithelium, Inflammation, Diffuse,                                                                                            
          Necrotizing                                                            1 (2%)                                             
   Penis                                              (5)          (4)          (2)                                                 
      Inflammation, Acute, Focal                       1 (20%)                   1 (50%)                                            
   Preputial Gland                                    (10)         (5)          (9)                                                 
      Abscess, Chronic, Focal                          3 (30%)      1 (20%)      1 (11%)                                            
      Abscess, Focal, Subacute                                                   1 (11%)                                            
      Bilateral, Abscess, Chronic                      2 (20%)                                                                      
      Bilateral, Inflammation, Granulomatous,                                                                                       
          Multifocal, Suppurative                      1 (10%)                                                                      
      Duct, Ectasia, Focal                             1 (10%)      1 (20%)      2 (22%)                                            
      Duct, Ectasia, Multifocal                        1 (10%)      1 (20%)      3 (33%)                                            
      Left, Abscess, Chronic, Focal                                 1 (20%)                                                         
      Right, Abscess, Chronic, Focal                   1 (10%)                                                                      
      Right, Abscess, Chronic Active, Focal                         1 (20%)                                                         
   Prostate                                           (48)         (49)         (49)                                                
      Dilatation                                                    1 (2%)       1 (2%)                                             
      Dilatation, Diffuse                                           2 (4%)       1 (2%)                                             
      Granuloma, Focal                                                           1 (2%)                                             
      Inflammation, Acute, Diffuse                     1 (2%)                    1 (2%)                                             
      Inflammation, Acute, Multifocal                                            5 (10%)                                            
      Inflammation, Acute, Multifocal, Suppurative                               1 (2%)                                             
      Inflammation, Multifocal, Necrotizing,                                                                                        
          Subacute                                                  1 (2%)                                                          
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   10                                                              
NTP Experiment-Test: 05052-02         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: 23:47:53  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
      Artery, Inflammation, Chronic, Multifocal                     1 (2%)                                                          
   Seminal Vesicle                                    (17)         (2)          (15)                                                
      Dilatation                                                                 3 (20%)                                            
      Dilatation, Diffuse                                           2 (100%)                                                        
      Inflammation, Acute, Focal                       1 (6%)                                                                       
      Lumen, Dilatation                                                          2 (13%)                                            
      Lumen, Dilatation, Diffuse                       1 (6%)                    1 (7%)                                             
      Parenchyma, Inflammation, Acute, Multifocal                                1 (7%)                                             
      Serosa, Inflammation, Acute, Diffuse                                       1 (7%)                                             
   Testes                                             (48)         (1)          (48)                                                
      Germinal Epithelium, Atrophy, Diffuse                                      1 (2%)                                             
      Germinal Epithelium, Atrophy, Focal              1 (2%)                                                                       
      Germinal Epithelium, Atrophy, Multifocal         1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Blood                                              (12)                      (6)                                                 
      Leukocytosis                                     1 (8%)                                                                       
      Neutrophilia                                                               1 (17%)                                            
   Bone Marrow                                        (50)                      (49)                                                
      Femoral, Hyperplasia, Diffuse, Neutrophil        1 (2%)                    1 (2%)                                             
      Femoral, Hypoplasia, Focal                       1 (2%)                                                                       
      Femoral, Thrombosis, Focal, Subacute                                       1 (2%)                                             
   Lymph Node                                         (48)         (11)         (47)                                                
      Inguinal, Hyperplasia, Diffuse, Lymphoid         1 (2%)                                                                       
      Inguinal, Infiltration Cellular, Diffuse,                                                                                     
           Plasma Cell                                 1 (2%)                                                                       
      Lumbar, Hemorrhage, Acute, Diffuse               1 (2%)                                                                       
      Lumbar, Hyperplasia, Diffuse, Plasma Cell        1 (2%)                                                                       
      Lumbar, Infiltration Cellular, Diffuse,                                                                                       
          Plasma Cell                                  1 (2%)                                                                       
      Lumbar, Infiltration Cellular, Diffuse,                                                                                       
          Polymorphonuclear                            1 (2%)                                                                       
      Lumbar, Infiltration Cellular, Focal, Plasma                                                                                  
          Cell                                                      1 (9%)                                                          
      Mandibular, Depletion Lymphoid, Diffuse                                    4 (9%)                                             
      Mandibular, Hematopoietic Cell Proliferation,                                                                                 
           Diffuse                                     1 (2%)                                                                       
      Mandibular, Hyperplasia, Diffuse, Lymphoid       1 (2%)                    1 (2%)                                             
      Mandibular, Infiltration Cellular, Diffuse,                                                                                   
           Plasma Cell                                 3 (6%)                    1 (2%)                                             
      Mediastinal, Depletion Lymphoid, Diffuse                                   1 (2%)                                             
      Mesenteric, Angiectasis, Diffuse                10 (21%)      4 (36%)      3 (6%)                                             
      Mesenteric, Angiectasis, Multifocal              1 (2%)       1 (9%)       1 (2%)                                             
      Mesenteric, Erythrophagocytosis, Diffuse         1 (2%)                                                                       
      Mesenteric, Hematopoietic Cell Proliferation,                                                                                 
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   11                                                              
NTP Experiment-Test: 05052-02         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: 23:47:53  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
           Diffuse                                     5 (10%)      1 (9%)                                                          
      Mesenteric, Inflammation, Chronic                                          1 (2%)                                             
      Pancreatic, Angiectasis, Diffuse                                           1 (2%)                                             
      Pancreatic, Angiectasis, Multifocal                           2 (18%)                                                         
      Pancreatic, Hematopoietic Cell Proliferation,                                                                                 
           Diffuse                                                  2 (18%)                                                         
      Pancreatic, Inflammation, Acute, Diffuse         1 (2%)                                                                       
   Spleen                                             (49)         (46)         (47)                                                
      Inflammation, Acute, Multifocal                                            1 (2%)                                             
      Capsule, Fibrosis, Focal                         1 (2%)                                                                       
      Lymphoid Follicle, Depletion Lymphoid,                                                                                        
          Multifocal                                   1 (2%)       4 (9%)      10 (21%)                                            
      Lymphoid Follicle, Hyperplasia, Diffuse                                    1 (2%)                                             
      Lymphoid Follicle, Hyperplasia, Diffuse,                                                                                      
           Lymphoid                                    1 (2%)                                                                       
      Lymphoid Follicle, Hyperplasia, Focal,                                                                                        
          Lymphoid                                     1 (2%)                                                                       
      Lymphoid Follicle, Necrosis, Acute,                                                                                           
          Multifocal                                                             1 (2%)                                             
      Red Pulp, Angiectasis, Multifocal                                          1 (2%)                                             
      Red Pulp, Hematopoietic Cell Proliferation,                                                                                   
           Diffuse                                    10 (20%)     11 (24%)      3 (6%)                                             
      Red Pulp, Infiltration Cellular, Focal,                                                                                       
          Plasma Cell                                  1 (2%)                                                                       
   Thymus                                             (38)                      (38)                                                
      Depletion Lymphoid, Diffuse                      3 (8%)                    2 (5%)                                             
      Cortex, Cyst, Single                                                       1 (3%)                                             
      Medulla, Cyst, Multiple                                                    1 (3%)                                             
      Thymocyte, Necrosis, Acute, Diffuse              1 (3%)                    8 (21%)                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Skin                                               (50)         (21)         (49)                                                
      Acanthosis, Diffuse                              1 (2%)                                                                       
      Acanthosis, Focal                                1 (2%)                                                                       
      Hyperkeratosis, Diffuse                          1 (2%)                                                                       
      Inflammation, Acute, Focal                       1 (2%)                                                                       
      Inflammation, Focal, Subacute                    1 (2%)                                                                       
      Necrosis, Acute, Diffuse                                                   1 (2%)                                             
      Abdominal, Inflammation, Chronic, Focal                                    1 (2%)                                             
      Abdominal, Ulcer, Acute, Focal                                             1 (2%)                                             
      Abdominal, Ulcer, Acute, Multifocal                                        2 (4%)                                             
      Back, Acanthosis, Focal                                                    2 (4%)                                             
      Back, Alopecia, Focal                                         1 (5%)                                                          
      Back, Fibrosis, Diffuse                          2 (4%)                                                                       
      Back, Fibrosis, Focal                            1 (2%)                    5 (10%)                                            
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   12                                                              
NTP Experiment-Test: 05052-02         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: 23:47:53  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
INTEGUMENTARY SYSTEM - CONT                                                                                                         
      Back, Fibrosis, Multifocal                                                 1 (2%)                                             
      Back, Hyperplasia, Diffuse,                                                                                                   
          Pseudoepitheliomatous                        1 (2%)                                                                       
      Back, Inflammation, Chronic, Diffuse             1 (2%)                                                                       
      Back, Inflammation, Chronic Active, Diffuse      1 (2%)                                                                       
      Back, Ulcer, Acute, Diffuse                      1 (2%)                                                                       
      Back, Ulcer, Acute, Focal                        3 (6%)                    2 (4%)                                             
      Back, Ulcer, Acute, Multifocal                                             1 (2%)                                             
      Back, Ulcer, Chronic Active, Focal               1 (2%)                                                                       
      Back, Ulcer, Chronic Active, Multifocal          2 (4%)                    1 (2%)                                             
      Dermis, Fibrosis, Focal                          1 (2%)                                                                       
      Dermis, Inflammation, Focal, Subacute            1 (2%)                                                                       
      Face, Ulcer, Chronic Active, Multifocal          1 (2%)                                                                       
      Face, Subcutaneous Tissue, Granuloma, Focal                                1 (2%)                                             
      Face, Subcutaneous Tissue, Inflammation,                                                                                      
           Chronic Active, Focal                       1 (2%)                                                                       
      Hindlimb, Subcutaneous Tissue, Inflammation,                                                                                  
           Chronic, Focal, Granulomatous                                         1 (2%)                                             
      Neck, Subcutaneous Tissue, Inflammation,                                                                                      
           Acute, Focal                                1 (2%)                                                                       
      Prepuce, Inflammation, Acute, Focal                           1 (5%)                                                          
      Prepuce, Inflammation, Acute, Focal,                                                                                          
          Necrotizing                                               2 (10%)                                                         
      Prepuce, Inflammation, Acute, Multifocal                                   1 (2%)                                             
      Prepuce, Inflammation, Acute, Multifocal,                                                                                     
           Necrotizing                                              1 (5%)                                                          
      Prepuce, Inflammation, Chronic, Focal,                                                                                        
          Necrotizing                                               1 (5%)       1 (2%)                                             
      Prepuce, Inflammation, Chronic Active, Focal                               1 (2%)                                             
      Prepuce, Inflammation, Focal, Granulomatous,                                                                                  
           Necrotizing                                              2 (10%)                                                         
      Prepuce, Ulcer, Acute, Focal                     1 (2%)                                                                       
      Right, Inflammation, Chronic Active, Focal       1 (2%)                                                                       
      Subcutaneous Tissue, Granuloma, Focal                                      1 (2%)                                             
      Subcutaneous Tissue, Granuloma, Multiple                                   1 (2%)                                             
      Subcutaneous Tissue, Inflammation, Acute,                                                                                     
           Diffuse                                                               1 (2%)                                             
      Subcutaneous Tissue, Inflammation, Acute,                                                                                     
           Focal                                       1 (2%)                    1 (2%)                                             
      Subcutaneous Tissue, Inflammation, Chronic,                                                                                   
           Diffuse                                     1 (2%)                                                                       
      Subcutaneous Tissue, Inflammation, Chronic,                                                                                   
           Focal                                                                 1 (2%)                                             
      Subcutaneous Tissue, Inflammation, Focal,                                                                                     
           Granulomatous                               1 (2%)                    3 (6%)                                             
      Thoracic, Fibrosis, Focal                        1 (2%)                                                                       
      Thoracic, Inflammation, Chronic Active,                                                                                       
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   13                                                              
NTP Experiment-Test: 05052-02         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: 23:47:53  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
INTEGUMENTARY SYSTEM - CONT                                                                                                         
          Diffuse                                                   1 (5%)                                                          
      Thoracic, Inflammation, Chronic Active, Focal                              1 (2%)                                             
      Thoracic, Ulcer, Chronic Active, Multifocal      1 (2%)                    1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (39)         (50)                                                
      Hyperostosis                                                  1 (3%)       1 (2%)                                             
      Bilateral, Joint, Tarsal, Arthrosis, Chronic    31 (62%)     33 (85%)     18 (36%)                                            
      Bilateral, Joint, Tarsal, Metaplasia,                                                                                         
          Diffuse, Osseous                                          1 (3%)                                                          
      Bilateral, Joint, Tarsal, Metaplasia,                                                                                         
          Multifocal, Osseous                                                    1 (2%)                                             
      Joint, Right, Tarsal, Inflammation, Chronic                                                                                   
          Active, Diffuse                              1 (2%)                                                                       
      Joint, Left, Tarsal, Metaplasia, Multifocal,                                                                                  
           Osseous                                                               1 (2%)                                             
      Joint, Tarsal, Arthrosis, Chronic                             1 (3%)                                                          
      Joint, Phalanges, Inflammation, Chronic                                                                                       
          Active, Focal                                             1 (3%)                                                          
      Unilateral, Joint, Tarsal, Arthrosis, Chronic    9 (18%)      1 (3%)      11 (22%)                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (1)          (50)                                                
      Hemorrhage, Acute, Multifocal                                 1 (100%)                                                        
      Cerebellum, Perivascular Cuffing, Focal          1 (2%)                                                                       
      Cerebrum, Inflammation, Acute, Focal                                       1 (2%)                                             
      Fourth Ventricle, Lateral Ventricle,                                                                                          
          Hydrocephalus                                                          1 (2%)                                             
      Lateral Ventricle, Hydrocephalus                                           1 (2%)                                             
      Meninges, Perivascular Cuffing, Focal            1 (2%)                                                                       
      Meninges, Perivascular Cuffing, Multifocal       1 (2%)                                                                       
      Thalamus, Mineralization                         2 (4%)                    3 (6%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (4)          (50)                                                
      Edema, Multifocal, Subacute                                                1 (2%)                                             
      Foreign Body, Multifocal                                                   5 (10%)                                            
      Hemorrhage, Diffuse, Subacute                    1 (2%)                                                                       
      Infarct, Acute, Multifocal                                    1 (25%)                                                         
      Infiltration Cellular, Diffuse, Histiocyte       1 (2%)                                                                       
      Infiltration Cellular, Focal, Histiocyte         1 (2%)                                                                       
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   14                                                              
NTP Experiment-Test: 05052-02         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: 23:47:53  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - CONT                                                                                                           
      Inflammation, Acute, Multifocal                  1 (2%)                                                                       
      Alveolar Epithelium, Hyperplasia, Focal          6 (12%)                   3 (6%)                                             
      Capillary, Infiltration Cellular, Acute,                                                                                      
           Diffuse, Polymorphonuclear                  1 (2%)                                                                       
      Capillary, Infiltration Cellular, Diffuse,                                                                                    
           Polymorphonuclear                           1 (2%)                                                                       
      Diaphragmatic Lobe, Right, Edema, Focal,                                                                                      
           Subacute                                                              1 (2%)                                             
      Interstitium, Infiltration Cellular, Acute,                                                                                   
           Diffuse, Polymorphonuclear                                            1 (2%)                                             
      Interstitium, Inflammation, Acute, Diffuse                                 1 (2%)                                             
      Interstitium, Inflammation, Acute, Multifocal                              1 (2%)                                             
      Interstitium, Inflammation, Multifocal,                                                                                       
          Subacute                                     1 (2%)                                                                       
      Mediastinum, Infiltration Cellular,                                                                                           
          Multifocal, Lymphocyte                                                 1 (2%)                                             
      Peribronchial, Infiltration Cellular,                                                                                         
          Multifocal, Lymphocyte                                                 1 (2%)                                             
      Right, Edema, Chronic, Diffuse                   1 (2%)                                                                       
   Nose                                               (43)                      (34)                                                
      Mucosa, Inflammation, Acute                      1 (2%)                                                                       
      Mucosa, Inflammation, Acute, Multifocal          2 (5%)                                                                       
      Nasolacrimal Duct, Inflammation, Acute,                                                                                       
          Multifocal                                   1 (2%)                                                                       
      Septum, Inflammation, Acute, Focal                                         1 (3%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (1)                       (1)                                                 
      Atrophy                                          1 (100%)                                                                     
   Harderian Gland                                    (44)         (3)          (30)                                                
      Hyperplasia, Focal                                            1 (33%)                                                         
      Bilateral, Hyperplasia, Multifocal                                         1 (3%)                                             
      Right, Hyperplasia, Focal                                                  1 (3%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (49)         (6)          (49)                                                
      Inflammation, Acute, Multifocal                                            2 (4%)                                             
      Inflammation, Chronic, Focal                                               1 (2%)                                             
      Inflammation, Multifocal, Subacute                            1 (17%)                                                         
      Bilateral, Infarct, Acute, Multifocal                         1 (17%)                                                         
      Bilateral, Inflammation, Acute, Multifocal,                                                                                   
           Suppurative                                              1 (17%)      1 (2%)                                             
      Bilateral, Inflammation, Chronic, Multifocal                               1 (2%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   15                                                              
NTP Experiment-Test: 05052-02         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: 23:47:53  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          0 PPM        5000 PPM     10000                                                  
                                                                             PPM                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
URINARY SYSTEM - CONT                                                                                                               
      Cortex, Cyst, Focal                              1 (2%)                                                                       
      Cortex, Infarct, Chronic, Focal                  1 (2%)                                                                       
      Cortex, Inflammation, Acute, Focal               1 (2%)                                                                       
      Cortex, Metaplasia, Focal, Osseous                                         1 (2%)                                             
      Cortex, Renal Tubule, Necrosis, Acute,                                                                                        
          Multifocal                                                             1 (2%)                                             
      Corticomedullary Junction, Angiectasis,                                                                                       
          Multifocal                                   1 (2%)                                                                       
      Corticomedullary Junction, Metaplasia, Focal,                                                                                 
           Osseous                                                               1 (2%)                                             
      Corticomedullary Junction, Mineralization,                                                                                    
           Multifocal                                                            4 (8%)                                             
      Corticomedullary Junction, Thrombosis,                                                                                        
          Chronic, Focal                               1 (2%)                                                                       
      Corticomedullary Junction, Renal Tubule,                                                                                      
           Mineralization, Multifocal                               1 (17%)                                                         
      Left, Inflammation, Chronic Active, Diffuse      1 (2%)                                                                       
      Pelvis, Inflammation, Acute, Diffuse                          1 (17%)                                                         
      Pelvis, Inflammation, Acute, Multifocal,                                                                                      
           Suppurative                                                           1 (2%)                                             
      Pelvis, Mineralization, Focal                                              1 (2%)                                             
      Renal Tubule, Cytoplasmic Alteration,                                                                                         
          Multifocal                                                             1 (2%)                                             
      Renal Tubule, Dilatation, Diffuse                             2 (33%)      2 (4%)                                             
      Renal Tubule, Dilatation, Focal                  1 (2%)                                                                       
      Renal Tubule, Necrosis, Acute, Diffuse                        1 (17%)                                                         
      Renal Tubule, Necrosis, Diffuse, Subacute        1 (2%)                                                                       
      Renal Tubule, Regeneration, Focal                3 (6%)                    4 (8%)                                             
      Renal Tubule, Regeneration, Multifocal           8 (16%)                   4 (8%)                                             
      Right, Atrophy                                                1 (17%)                                                         
      Right, Inflammation, Chronic Active, Diffuse                  1 (17%)                                                         
   Urethra                                                         (2)                                                              
      Concretion, Focal                                             2 (100%)                                                        
      Transitional Epithelium, Necrosis, Acute,                                                                                     
           Focal                                                    1 (50%)                                                         
   Urinary Bladder                                    (48)         (3)          (46)                                                
      Calculus Gross Observation                                    1 (33%)                                                         
      Lumen, Ectasia                                                2 (67%)                                                         
      Mucosa, Necrosis, Focal, Single                                            1 (2%)                                             
      Serosa, Inflammation, Acute, Multifocal                                    1 (2%)                                             
      Submucosa, Inflammation, Acute, Diffuse          1 (2%)       1 (33%)                                                         
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   16                                                              
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NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.