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Thyroid Gland - C Cell Hyperplasia
comment:
C-cell hyperplasia is a common finding in chronic rat studies and can be diffuse ( Figure 1
and
Figure 2
), focal (
Figure 3
and
Figure 4
), or multifocal. C-cell hyperplasia is distinguished from C-cell adenoma based on the size of any given focal proliferation. The generally accepted criteria for C-cell hyperplasia is a focal C-cell cluster less than five average follicular diameters or similarly small-sized clusters of C cells scattered in interfollicular spaces. In contrast to C-cell adenomas, C-cell hyperplasia is not associated with significant compression of adjacent parenchyma. C-cell hyperplasias may contain individual trapped follicles (
Figure 1
and
Figure 2
). C-cell hyperplasia generally consists of round to polyhedral cells with abundant eosinophilic cytoplasm (
Figure 2
); in some cases there is a higher than typical nuclear-to-cytoplasmic ratio (
Figure 4
).recommendation:
C-cell hyperplasia should be diagnosed when present, given a severity grade. If bilateral it should be indicated in the diagnosis with a severity grade based on the more severely affected thyroid gland.references:
Capen CC, Martin SL. 1989. The effects of xenobiotics on the structure and function of thyroid follicular and C-cells. Toxicol Pathol 17:266-293. Abstract: http://www.ncbi.nlm.nih.gov/pubmed/2675279
Capen CC, DeLellis RA, Yarrington JT. 2002. Endocrine system. In: Handbook of Toxicologic Pathology, Vol 2 (Haschek WM, Rousseaux CG, Wallig MA, eds). Academic Press, New York, 681–783. Abstract: http://www.sciencedirect.com/science/book/9780123302151
Chandra S, Hoenerhoff MJ, Peterson R. 2013. Endocrine glands. In: Toxicologic Pathology: Nonclinical Safety Assessment (Sahota PS, Popp JA, Hardisty JF, Gopinath G, eds). CRC Press, Boca Raton, FL, 655-716. Abstract: http://www.crcpress.com/product/isbn/9781439872109
Collins WT, Capen CC, Kasza L, Carter C, Dailey RE. 1977. Effect of polychlorinated biphenyl (PCB) on the thyroid gland of rats. Ultrastructural and biochemical investigations. Am J Pathol 89:119-136. Abstract: http://www.ncbi.nlm.nih.gov/pubmed/199066
Greaves P. 2007. Histopathology of Preclinical Toxicity Studies: Interpretation and Relevance in Drug Safety Evaluation, 3rd ed. Academic Press, Amsterdam, 819-839. Abstract: http://www.sciencedirect.com/science/book/9780444527714
Hardisty JF, Boorman GA. 1990. Thyroid gland. In: Pathology of the Fischer Rat: Reference and Atlas (Boorman GA, Eustis SL, Elwell MR, Montgomery CA, MacKenzie WF, eds). Academic Press, San Diego, 519–536. Abstract: http://www.ncbi.nlm.nih.gov/nlmcatalog/9002563
