Thymus - Atypical Hyperplasia Lymphocyte

comment:
Atypical hyperplasia of the thymic lymphocytes has been described in chemically treated B6C3F1 and p53-deficient mice. This lesion also occurs in other mouse strains that develop thymic lymphomas and possibly in rats with chemically induced thymic lymphomas. It may be unilateral or bilateral; when unilateral, the unaffected lobe is typically larger than the abnormal lobe ( Figure 1

recommendation:
Whenever present, atypical hyperplasia of the thymic lymphocytes should be diagnosed and assigned a severity grade. It should be noted in the pathology narrative whether the lesion is present in one or both thymic lobes.references:
Dunnick JK, Hardisty JF, Herbert RA, Seely JC, Furedi-Machacek EM, Foley JF, Lacks GD, Stasiewicz S, French JE. 1997. Phenolphthalein induces thymic lymphomas accompanied by loss of the p53 wild type allele in heterozygous p53-deficient (+/-) mice. Toxicol Pathol 25:533-540. Abstract: http://www.ncbi.nlm.nih.gov/pubmed/9437796
National Toxicology Program. 2007. NTP GMM-12. Toxicology and Carcinogenesis Study of Phenolphthalein (CAS No. 77-09-8) in Genetically Modified Haploinsufficient p16Ink4a/p19Arf Mice (Feed Study). NTP, Research Triangle Park, NC. Abstract: http://ntp.niehs.nih.gov/go/28495
Pearse G. 2006. Histopathology of the thymus. Toxicol Pathol 34:515-547. Full Text: http://tpx.sagepub.com/content/34/5/515.long
Ward JM, Mann PC, Morishima H, Frith CH. 1999. Thymus, spleen, and lymph nodes. In: Pathology of the Mouse (Maronpot RR, ed). Cache River Press, Vienna, IL, 333-360.
Ward JM, Tadesse-Heath L, Perkins SN, Chattopadhyay SK, Hursting SD, Morse HC 3rd. 1999. Splenic marginal zone B-cell and thymic T-cell lymphomas in p53-deficient mice. Lab Invest 79:3-14. Abstract: http://www.ncbi.nlm.nih.gov/pubmed/9952106
Web page last updated on: February 03, 2015