Liver - Focus




comment:
Foci of cellular alteration, diagnosed simply as “foci” in NTP studies, can occur spontaneously in rats and mice but may also be induced by treatment. They range from less than a lobule to several lobules in size. Foci are presumptive preneoplastic lesions that can vary from barely perceptible to cytomorphologically and tinctorially discrete lesions. Foci typically blend imperceptibly with, and do not compress, surrounding hepatic parenchyma, though minimal compression may occur. Foci are relatively common in chronic studies but uncommon in 90-day studies. They are subclassified based on hematoxylin and eosin tinctorial properties and cytoplasmic features.Basophilic foci predominantly stain with hematoxylin ( Figure 1










recommendation:
Because foci are presumptive preneoplastic lesions, they should be diagnosed whenever present. The current NTP recommendation is to document all foci and to classify these into subtypes (basophilic, eosinophilic, clear cell, or mixed). A severity grade is not required for foci unless the pathologist feels it is necessary to highlight differences among the study groups.related links:
Liver, Hepatocyte - Glycogen Accumulation and Depletionreferences:
Eustis SL, Boorman GA, Harada T, Popp JA. 1990. Liver. In: Pathology of the Fischer Rat (Boorman GA, Eustis SL, Elwell MR, Montgomery CA, MacKenzie WF, eds). Academic Press, San Diego, 71-94.
Harada T, Enomoto A, Boorman GA, Maronpot RR. 1999. Liver and gallbladder. In: Pathology of the Mouse: Reference and Atlas (Maronpot RR, Boorman GA, Gaul BW, eds). Cache River Press, Vienna, IL, 119-183. Abstract: http://www.cacheriverpress.com/books/pathmouse.htm
Harada T, Maronpot RR, Enomoto A, Tamano S, Ward JM. 1996. Changes in the liver and gallbladder. In: Pathobiology of the Aging Mouse (Mohr U, Dungworth DL, Capen CC, Carlton WW, Sundberg JP, Ward JM, eds). ILSI Press, Washington, DC, 2:207-241. Abstract: http://catalog.hathitrust.org/Record/008994685
Harada T, Maronpot RR, Morris RW, Stitzel KA, Boorman GA. 1989. Morphological and stereological characterization of hepatic foci of cellular alteration in control Fischer 344 rats. Toxicol Pathol 17:579-593. Abstract: https://www.ncbi.nlm.nih.gov/pubmed/2483465
Maronpot RR, Harada T, Murthy ASK, Boorman GA. 1989. Documenting foci of hepatocellular alteration in two-year carcinogenicity studies: Current practices of the National Toxicology Program. Toxicol Pathol 17:675-684. Abstract: https://www.ncbi.nlm.nih.gov/pubmed/2697942
National Toxicology Program. 2011. NTP TOX-82. 3-Month Toxicity Studies of Estragole (CAS No. 140-67-0) Administered by Gavage to F344/N Rats and B6C3F1 Mice. NTP, Research Triangle Park, NC. Full Text: https://ntp.niehs.nih.gov/ntp/htdocs/ST_rpts/tox082.pdf
National Toxicology Program. 2011. NTP TR-563. Toxicology and Carcinogenesis Studies of Pulegone (CAS No. 89-82-7) in F344/N Rats and B6C3F1 Mice (Gavage Studies). NTP, Research Triangle Park, NC. Full Text: https://ntp.niehs.nih.gov/ntp/htdocs/LT_rpts/TR563.pdf
Thoolen B, Maronpot RR, Harada T, Nyska A, Rousseaux C, Nolte T, Malarkey D, Kaufmann W, Kutter K, Deschl U, Nakae D, Gregson R, Winlove M, Brix A, Singl B, Belpoggi F, Ward JM. 2010. Hepatobiliary lesion nomenclature and diagnostic criteria for lesions in rats and mice (INHAND). Toxicol Pathol 38:5S-81S. Full Text: http://tpx.sagepub.com/content/38/7_suppl/5S.full
Web page last updated on: November 04, 2016