National Toxicology Program

National Toxicology Program
https://ntp.niehs.nih.gov/go/2334

TDMS Study 05150-01 Pathology Tables


                              INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)
                                                   METHLYPHENIDATE HYDROCHLORIDE


NTP Experiment-Test: 05150-01                                                                                     Report: PEIRPT05
Study Type: CHRONIC                                                                                               Date: 05/20/95
Route: DOSED FEED                                                                                                 Time: 09:09:25




       Facility:  TSI Mason Research

       Chemical CAS #:  298-59-9

       Lock Date:  02/06/92

       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: 05150-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                   METHLYPHENIDATE HYDROCHLORIDE                               Date: 05/20/95  
Route: DOSED FEED                                                                                                 Time: 09:09:25  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   0 PPM        100 PPM      500 PPM      1000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially in Study                          70           70           70           70                                     
  Scheduled Sacrifice                                 20           20           20           20                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                13           12           10            7                                     
    Natural Death                                      6            6            4            4                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                29           30           36           38                                     
    Moribund Sacrifice                                 1                                      1                                     
    Natural Death                                                   2                                                               
    Dead                                               1                                                                            
  Animals Examined Microscopically                    70           70           70           70                                     
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Colon                             (67)         (67)         (69)         (69)                                   
      Fibroma                                                                                 1 (1%)                                
   Intestine Small, Duodenum                          (67)         (66)         (70)         (69)                                   
      Sarcoma Stromal, Metastatic, Uterus              1 (1%)                                                                       
   Intestine Small, Jejunum                           (67)         (63)         (68)         (68)                                   
   Intestine Small, Ileum                             (66)         (63)         (67)         (68)                                   
      Sarcoma                                                                                 1 (1%)                                
   Liver                                              (70)         (70)         (70)         (70)                                   
      Hepatocellular Adenoma                                        1 (1%)                                                          
      Sarcoma Stromal, Metastatic, Uterus              1 (1%)                                                                       
   Mesentery                                          (4)          (7)          (9)          (3)                                    
      Sarcoma Stromal, Metastatic, Uterus              1 (25%)                                                                      
   Pancreas                                           (70)         (69)         (70)         (70)                                   
      Sarcoma Stromal, Metastatic, Uterus              1 (1%)                                                                       
   Salivary Glands                                    (70)         (70)         (70)         (70)                                   
   Stomach, Forestomach                               (70)         (68)         (70)         (70)                                   
      Squamous Cell Papilloma                                       1 (1%)                                                          
   Stomach, Glandular                                 (70)         (69)         (70)         (70)                                   
   Tongue                                                                       (1)          (1)                                    
      Squamous Cell Papilloma                                                    1 (100%)     1 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (70)         (70)         (70)         (70)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                             Page   2                                                               
NTP Experiment-Test: 05150-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                   METHLYPHENIDATE HYDROCHLORIDE                               Date: 05/20/95  
Route: DOSED FEED                                                                                                 Time: 09:09:25  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   0 PPM        100 PPM      500 PPM      1000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Medulla                                    (70)         (69)         (70)         (70)                                   
      Pheochromocytoma Malignant                                    1 (1%)       2 (3%)                                             
      Pheochromocytoma Benign                          3 (4%)       3 (4%)       3 (4%)       3 (4%)                                
   Islets, Pancreatic                                 (70)         (69)         (70)         (70)                                   
      Adenoma                                                       2 (3%)       1 (1%)       2 (3%)                                
   Parathyroid Gland                                  (67)         (66)         (65)         (61)                                   
      Adenoma                                                       1 (2%)                                                          
   Pituitary Gland                                    (70)         (69)         (69)         (67)                                   
      Pars Distalis, Adenoma                          28 (40%)     30 (43%)     17 (25%)     22 (33%)                               
      Pars Distalis, Adenoma, Multiple                              3 (4%)       5 (7%)       3 (4%)                                
      Pars Distalis, Carcinoma                                                   1 (1%)                                             
   Thyroid Gland                                      (70)         (70)         (70)         (70)                                   
      C-Cell, Adenoma                                  4 (6%)       8 (11%)      7 (10%)      4 (6%)                                
      C-Cell, Carcinoma                                1 (1%)       2 (3%)                    1 (1%)                                
      Follicular Cell, Adenoma                                      1 (1%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (65)         (68)         (69)         (69)                                   
      Adenoma                                          1 (2%)       1 (1%)       1 (1%)                                             
   Ovary                                              (70)         (70)         (70)         (70)                                   
      Adenoma, Tubular                                                           1 (1%)                                             
      Granulosa Cell Tumor Benign                      1 (1%)                                                                       
   Uterus                                             (70)         (70)         (70)         (70)                                   
      Leiomyoma                                                                               1 (1%)                                
      Polyp Stromal                                    5 (7%)       9 (13%)     11 (16%)      8 (11%)                               
      Polyp Stromal, Two                                                                      1 (1%)                                
      Sarcoma Stromal                                  2 (3%)       1 (1%)       1 (1%)       1 (1%)                                
   Vagina                                             (1)          (1)          (4)          (1)                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Blood                                              (2)                       (1)          (1)                                    
   Bone Marrow                                        (70)         (70)         (70)         (70)                                   
   Lymph Node                                         (8)          (6)          (12)         (8)                                    
   Lymph Node, Mandibular                             (70)         (70)         (70)         (69)                                   
      Fibrosarcoma, Metastatic, Skin                                1 (1%)                                                          
   Lymph Node, Mesenteric                             (70)         (69)         (68)         (70)                                   
      Sarcoma Stromal, Metastatic, Uterus              1 (1%)                                                                       
                                                             Page   3                                                               
NTP Experiment-Test: 05150-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                   METHLYPHENIDATE HYDROCHLORIDE                               Date: 05/20/95  
Route: DOSED FEED                                                                                                 Time: 09:09:25  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   0 PPM        100 PPM      500 PPM      1000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - cont                                                                                                         
   Spleen                                             (70)         (69)         (70)         (70)                                   
   Thymus                                             (68)         (68)         (70)         (65)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (69)         (69)         (66)         (70)                                   
      Adenocarcinoma                                   1 (1%)       4 (6%)       1 (2%)       1 (1%)                                
      Adenoma                                                                    1 (2%)                                             
      Fibroadenoma                                    10 (14%)     12 (17%)      6 (9%)       3 (4%)                                
      Fibroadenoma, Multiple                           5 (7%)       1 (1%)                    2 (3%)                                
      Fibrosarcoma                                     1 (1%)                                                                       
   Skin                                               (70)         (70)         (69)         (70)                                   
      Basal Cell Adenoma                               1 (1%)       1 (1%)                    1 (1%)                                
      Fibroma                                                       2 (3%)                                                          
      Fibrosarcoma                                                  1 (1%)                                                          
      Keratoacanthoma                                                                         1 (1%)                                
      Sarcoma                                                       1 (1%)       1 (1%)                                             
      Trichoepithelioma                                1 (1%)                                                                       
      Pinna, Neurofibroma                                                                     1 (1%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (70)         (70)         (70)         (70)                                   
      Osteosarcoma                                                                            1 (1%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (70)         (70)         (69)         (70)                                   
      Astrocytoma Malignant                                         1 (1%)                                                          
      Carcinoma, Metastatic, Pituitary Gland                                     1 (1%)                                             
   Spinal Cord                                                                  (1)          (1)                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (70)         (70)         (70)         (70)                                   
      Alveolar/Bronchiolar Adenoma                                  3 (4%)                                                          
      Carcinoma, Metastatic, Thyroid Gland                          1 (1%)                                                          
      Fibrosarcoma, Metastatic, Skin                                1 (1%)                                                          
      Pheochromocytoma Malignant, Metastatic,                                                                                       
          Adrenal Medulla                                           1 (1%)                                                          
      Squamous Cell Carcinoma, Metastatic, Ear         1 (1%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                             Page   4                                                               
NTP Experiment-Test: 05150-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                   METHLYPHENIDATE HYDROCHLORIDE                               Date: 05/20/95  
Route: DOSED FEED                                                                                                 Time: 09:09:25  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   0 PPM        100 PPM      500 PPM      1000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Ear                                                (1)                                                                           
      Squamous Cell Carcinoma, Metastatic, Ear         1 (100%)                                                                     
   Zymbal's Gland                                     (1)          (1)          (1)                                                 
      Carcinoma                                                                  1 (100%)                                           
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (70)         (69)         (68)         (69)                                   
      Lipoma                                                                     1 (1%)                                             
      Renal Tubule, Adenoma                                         1 (1%)                    2 (3%)                                
   Urinary Bladder                                    (67)         (64)         (67)         (68)                                   
      Papilloma                                                                  1 (1%)       1 (1%)                                
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SYSTEMIC LESIONS                                                                                                                   
   Multiple Organs                                   *(70)        *(70)        *(70)        *(70)                                   
      Leukemia Mononuclear                            13 (19%)     14 (20%)     14 (20%)     13 (19%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
     *   Number of animals with any tissue examined microscopically                                                                 
                                                             Page   5                                                               
NTP Experiment-Test: 05150-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                   METHLYPHENIDATE HYDROCHLORIDE                               Date: 05/20/95  
Route: DOSED FEED                                                                                                 Time: 09:09:25  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   0 PPM        100 PPM      500 PPM      1000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
TUMOR SUMMARY                                                                                                                       
                                                                                                                                    
   Total Animals with Primary Neoplasms (b)            49          51          50          46                                       
     Total Primary Neoplasms                           77         105          77          75                                       
                                                                                                                                    
   Total Animals with Benign Neoplasms                 43          48          42          38                                       
     Total Benign Neoplasms                            59          80          56          57                                       
                                                                                                                                    
   Total Animals with Malignant Neoplasms              18          22          20          17                                       
     Total Malignant Neoplasms                         18          25          21          18                                       
                                                                                                                                    
   Total Animals with Metastatic Neoplasms              2           3           1                                                   
     Total Metastatic Neoplasm                          7           4           1                                                   
                                                                                                                                    
   Total Animals with Malignant Neoplasms                                                                                           
   Uncertain Primary Site                                                                                                           
                                                                                                                                    
   Total Animals with Neoplasms Uncertain-                                                                                          
   Benign or Malignant                                                                                                              
     Total Uncertain Neoplasms                                                                                                      
                                                                                                                                    
____________________________________________________________________________________________________________________________________
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Primary tumors: all tumors except metastatic tumors                                                                              
                                                             Page   6                                                               
NTP Experiment-Test: 05150-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                   METHLYPHENIDATE HYDROCHLORIDE                               Date: 05/20/95  
Route: DOSED FEED                                                                                                 Time: 09:09:25  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     0 PPM        100 PPM      500 PPM      1000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially in Study                          70           70           70           70                                     
  Scheduled Sacrifice                                 20           20           20           19                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                14            9            7            9                                     
    Natural Death                                      8            7            9            8                                     
    Accidently Killed                                               1                                                               
  Survivors                                                                                                                         
    Terminal Sacrifice                                28           33           34           33                                     
    Natural Death                                                                             1                                     
  Animals Examined Microscopically                    70           70           70           70                                     
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Colon                             (66)         (66)         (65)         (66)                                   
   Intestine Large, Rectum                            (68)         (67)         (68)         (69)                                   
   Intestine Large, Cecum                             (66)         (64)         (64)         (63)                                   
      Lipoma                                                        1 (2%)                                                          
      Polyp                                                                                   1 (2%)                                
   Intestine Small, Duodenum                          (66)         (69)         (66)         (67)                                   
   Intestine Small, Jejunum                           (65)         (66)         (64)         (65)                                   
   Intestine Small, Ileum                             (66)         (63)         (62)         (64)                                   
   Liver                                              (70)         (70)         (70)         (70)                                   
      Hepatocellular Adenoma                                        2 (3%)                                                          
      Histiocytic Sarcoma                                                                     1 (1%)                                
   Mesentery                                          (6)          (7)          (14)         (14)                                   
   Pancreas                                           (69)         (70)         (69)         (69)                                   
      Acinus, Adenoma                                                            2 (3%)       1 (1%)                                
   Stomach, Glandular                                 (68)         (70)         (68)         (70)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (70)         (70)         (70)         (70)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (70)         (69)         (69)         (69)                                   
      Adenoma                                                       1 (1%)                                                          
   Adrenal Medulla                                    (69)         (68)         (69)         (69)                                   
      Pheochromocytoma Malignant                       1 (1%)       1 (1%)       1 (1%)                                             
      Pheochromocytoma Benign                         12 (17%)      5 (7%)       5 (7%)      11 (16%)                               
                                                             Page   7                                                               
NTP Experiment-Test: 05150-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                   METHLYPHENIDATE HYDROCHLORIDE                               Date: 05/20/95  
Route: DOSED FEED                                                                                                 Time: 09:09:25  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     0 PPM        100 PPM      500 PPM      1000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - cont                                                                                                             
      Bilateral, Pheochromocytoma Benign               5 (7%)       1 (1%)                                                          
   Islets, Pancreatic                                 (69)         (70)         (70)         (69)                                   
      Adenoma                                          1 (1%)                    1 (1%)       2 (3%)                                
      Carcinoma                                                     2 (3%)                    2 (3%)                                
   Parathyroid Gland                                  (67)         (66)         (68)         (63)                                   
      Adenoma                                                                                 1 (2%)                                
   Pituitary Gland                                    (68)         (69)         (68)         (70)                                   
      Pars Distalis, Adenoma                          11 (16%)     11 (16%)      7 (10%)     11 (16%)                               
      Pars Distalis, Adenoma, Multiple                 1 (1%)                                                                       
      Pars Distalis, Carcinoma                         1 (1%)                                                                       
   Thyroid Gland                                      (70)         (69)         (70)         (69)                                   
      Schwannoma Malignant, Metastatic, Skin                                     1 (1%)                                             
      Bilateral, C-Cell, Adenoma                                                              1 (1%)                                
      C-Cell, Adenoma                                  4 (6%)       5 (7%)       6 (9%)       8 (12%)                               
      C-Cell, Carcinoma                                1 (1%)                    2 (3%)       1 (1%)                                
      Follicular Cell, Adenoma                         1 (1%)                                                                       
      Follicular Cell, Carcinoma                                    1 (1%)       1 (1%)       1 (1%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Coagulating Gland                                                                         (1)                                    
      Adenoma                                                                                 1 (100%)                              
   Epididymis                                         (70)         (69)         (70)         (70)                                   
   Preputial Gland                                    (70)         (67)         (70)         (70)                                   
      Adenoma                                          2 (3%)       2 (3%)       2 (3%)       1 (1%)                                
      Carcinoma                                                     2 (3%)       4 (6%)       2 (3%)                                
   Prostate                                           (69)         (70)         (69)         (70)                                   
   Seminal Vesicle                                    (68)         (70)         (69)         (70)                                   
   Testes                                             (70)         (69)         (70)         (70)                                   
      Bilateral, Interstitial Cell, Adenoma           50 (71%)     47 (68%)     51 (73%)     51 (73%)                               
      Interstitial Cell, Adenoma                       5 (7%)       9 (13%)      4 (6%)       6 (9%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Blood                                                           (1)                                                              
   Bone Marrow                                        (69)         (70)         (70)         (70)                                   
      Histiocytic Sarcoma                                                                     1 (1%)                                
      Osteosarcoma, Metastatic, Bone                                             1 (1%)                                             
   Lymph Node                                         (12)         (19)         (16)         (11)                                   
      Mediastinal, Histiocytic Sarcoma                                                        1 (9%)                                
                                                             Page   8                                                               
NTP Experiment-Test: 05150-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                   METHLYPHENIDATE HYDROCHLORIDE                               Date: 05/20/95  
Route: DOSED FEED                                                                                                 Time: 09:09:25  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     0 PPM        100 PPM      500 PPM      1000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - cont                                                                                                         
      Pancreatic, Histiocytic Sarcoma                                                         1 (9%)                                
   Lymph Node, Mandibular                             (68)         (69)         (68)         (70)                                   
      Histiocytic Sarcoma                                                                     1 (1%)                                
   Lymph Node, Mesenteric                             (69)         (70)         (68)         (69)                                   
      Histiocytic Sarcoma                                                                     1 (1%)                                
   Spleen                                             (70)         (70)         (70)         (70)                                   
      Hemangiosarcoma                                  2 (3%)                                                                       
      Histiocytic Sarcoma                                                                     1 (1%)                                
   Thymus                                             (59)         (67)         (67)         (68)                                   
      Histiocytic Sarcoma                                                                     1 (1%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (57)         (53)         (53)         (61)                                   
      Fibroadenoma                                     1 (2%)       2 (4%)       1 (2%)       2 (3%)                                
   Skin                                               (70)         (70)         (68)         (70)                                   
      Basal Cell Adenoma                                            2 (3%)                                                          
      Fibroma                                          1 (1%)       3 (4%)       1 (1%)       3 (4%)                                
      Fibrosarcoma                                     1 (1%)                                                                       
      Keratoacanthoma                                  1 (1%)       1 (1%)       4 (6%)       1 (1%)                                
      Sarcoma                                                       1 (1%)       1 (1%)                                             
      Squamous Cell Papilloma                          1 (1%)                    1 (1%)                                             
      Subcutaneous Tissue, Schwannoma Malignant                                  1 (1%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (69)         (70)         (70)         (70)                                   
      Chordoma                                                                   1 (1%)                                             
      Osteosarcoma                                                               1 (1%)                                             
   Skeletal Muscle                                    (1)                       (6)                                                 
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (70)         (70)         (70)         (70)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (70)         (70)         (70)         (70)                                   
      Alveolar/Bronchiolar Adenoma                     2 (3%)       1 (1%)                                                          
      Histiocytic Sarcoma                                                                     1 (1%)                                
      Schwannoma Malignant, Metastatic, Skin                                     1 (1%)                                             
   Nose                                               (70)         (69)         (69)         (70)                                   
      Polyp                                                                                   1 (1%)                                
                                                             Page   9                                                               
NTP Experiment-Test: 05150-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                   METHLYPHENIDATE HYDROCHLORIDE                               Date: 05/20/95  
Route: DOSED FEED                                                                                                 Time: 09:09:25  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     0 PPM        100 PPM      500 PPM      1000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - cont                                                                                                           
      Squamous Cell Carcinoma                                                                 1 (1%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Ear                                                (3)                                    (1)                                    
      Carcinoma, Metastatic, Pituitary Gland           1 (33%)                                                                      
   Zymbal's Gland                                                               (1)                                                 
      Carcinoma                                                                  1 (100%)                                           
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (69)         (70)         (70)         (67)                                   
      Lipoma                                                                                  1 (1%)                                
      Sarcoma                                          1 (1%)                                                                       
      Renal Tubule, Adenoma                                         1 (1%)                                                          
   Urinary Bladder                                    (63)         (64)         (63)         (64)                                   
      Papilloma                                                                               1 (2%)                                
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SYSTEMIC LESIONS                                                                                                                   
   Multiple Organs                                   *(70)        *(70)        *(70)        *(70)                                   
      Histiocytic Sarcoma                                                                     1 (1%)                                
      Leukemia Mononuclear                            29 (41%)     25 (36%)     17 (24%)     23 (33%)                               
      Mesothelioma Malignant                           1 (1%)                    3 (4%)       2 (3%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
     *   Number of animals with any tissue examined microscopically                                                                 
                                                             Page  10                                                               
NTP Experiment-Test: 05150-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                   METHLYPHENIDATE HYDROCHLORIDE                               Date: 05/20/95  
Route: DOSED FEED                                                                                                 Time: 09:09:25  
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         FISCHER 344 RATS MALE                     0 PPM        100 PPM      500 PPM      1000 PPM                                  
                                                                                                                                    
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TUMOR SUMMARY                                                                                                                       
                                                                                                                                    
   Total Animals with Primary Neoplasms (b)            57          57          56          57                                       
     Total Primary Neoplasms                          135         126         118         137                                       
                                                                                                                                    
   Total Animals with Benign Neoplasms                 56          57          55          57                                       
     Total Benign Neoplasms                            98          94          85         104                                       
                                                                                                                                    
   Total Animals with Malignant Neoplasms              32          28          27          30                                       
     Total Malignant Neoplasms                         37          32          33          33                                       
                                                                                                                                    
   Total Animals with Metastatic Neoplasms              1                       4           1                                       
     Total Metastatic Neoplasm                          1                       5           1                                       
                                                                                                                                    
   Total Animals with Malignant Neoplasms                                                                                           
   Uncertain Primary Site                                                                                                           
                                                                                                                                    
   Total Animals with Neoplasms Uncertain-                                                                                          
   Benign or Malignant                                                                                                              
     Total Uncertain Neoplasms                                                                                                      
                                                                                                                                    
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a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Primary tumors: all tumors except metastatic tumors                                                                              
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NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.