Male and female 35 and 70 day old Sprague Dawley rats

SIGNALMENT: (age, breed, sex, species, and scientific name) 
Male and female 35 and 70 day old Sprague Dawley rats.

TREATMENT PROTOCOL: (including test compound identification, dose, and class of molecule)
These rats were the offspring(F1) of a group of rats which were fed PCBs(Aroclor 1254) from day 0 of pregnancy until weaning at 23 days of age. The Aroclor was incorporated into their lab chow to deliver a dose of 15 mg / kg/ day. The rats were necropsied at 35(427 female, 2503 male, 5507 female) and 70(2005 female, 6703 male) days of age.   

No changes noted

LABORATORY RESULTS: (clinical pathology, microbiology, etc…)
Non available


  1. Liver , focal fibrosis and hepatocellular atrophy, mild (6703)
  2. Liver , focal fibroacinar formation (2503, 2005)
  3. Liver , hepatocellular adenocarcinoma , focal(5507) and diffuse (427)
  4. Liver , hepatocellular acinar formation(427)
    Etiology: PCBs - Aroclor 1254 ingestion

CONTRIBUTOR'S COMMENTS:  (Proposed pathogenesis of the lesion(s), important considerations and diagnostic features, discussion of controversial issues).

PCBs have been well documented to be carcinogenic in laboratory animals and may be carcinogenic in humans(1,2) In these liver slides a range of lesions is present including : (1) focal hepatocellular atrophy with loss of hepatocytes and fibrosis (2) focal fibroacinar formation (3)hepatocellular acinar formation (4) hepatocellular adenocarcinoma formation. The ability of hepatocytes to transform into acinar structures was a striking feature.

REFERENCES: (Please submit a photocopy of each reference.)

1   U.S. Environmental Protection Agency (Sept 1996) PCBs : Cancer Dose-Response Assessment and Application to Environmental Mixtures   Report No.  EPA/600/P - 96 /001F

2   ATSDR (Agency for Toxic Substances and Disease Registry) (Nov  2000) Polychlorinated Biphenyls (Update)   


Treated vs Control, Objective of the microscope (2x, 4x, 10x, 20x, 40x, 100x) or the magnification of Electron Micrographs, Type of stain used (H&E, PAS, Trichrome, Osmium, etc.), and Descriptive legend that explains and describes the features in that image. If the contributor wishes to include labels on the images, a separate set of unlabeled images should also be submitted so that RTPA members can examine the case as an unknown first.

Image 1   (6703)  70 day male 40 obj   H&E
Legend: Focal fibrosis and hepatocellular atrophy  

Image 2  (2005) 70 day female 40 obj  H&E
Legend: Focal fibroacinar formation 

Image 3   (2503) 35 day male 20 obj  H&E
Legend: Focal fibroacinar formation 

Image 4 (5507) 35 day female 20 obj H&E
Legend: Hepatocellular adenocarcinoma formation with invasive growth 

Image 5 (427) 35 day female 10 obj H&E
Legend: Generalized hepatocellular adenocarcinoma 

Image 6 (427) 35 day female 40 obj H&E
Legend: Hepatocellular acinar formation 

Image 7 (427) 35 day female 5 obj Masson Trichrome stain
Legend: Abundant liver fibrosis associated with adenocarcinoma  



70 day male 40x H&E 


70 day female 40x H&E


35 day male 20x H&E


35 day female 40x H&E


35 day female 10x H&E



35 day female 40x H&E



35 day female 5x H&E

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