Parathyroid Gland - Hyperplasia, Focal



comment:
Parathyroid hyperplasia can be focal or diffuse and occurs in low incidence in rats and rarely in mice. Focal hyperplasia is a combination of hyperplasia and hypertrophy, with the hyperplastic foci standing out from the normal parathyroid parenchyma by virtue of structural alteration of the normal cords and/or differential tinctorial staining of the enlarged hypertrophic cells comprising the focal hyperplasia. There is negligible compression of surrounding parenchyma; in contrast, parathyroid adenomas cause compression of adjacent tissue and tend to be larger than hyperplasias. Severe focal hyperplasia can result in a grossly enlarged parathyroid. Focal parathyroid hyperplasia is potentially preneoplastic.recommendation:
Focal parathyroid hyperplasia should be diagnosed and assigned a severity grade. If both parathyroids are involved, the diagnosis should be qualified as bilateral and the severity grade based on the more severely affect gland.references:
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
Rosol TJ, Capen CC. 1989. Tumors of the parathyroid gland and circulating parathyroid hormone-related protein associated with persistent hypercalcemia. Toxicol Pathol 17:346-356. Full Text: http://tpx.sagepub.com/content/17/2/346.full.pdf
Seely JC, Hildebrandt PK.. 1990. Parathyroid 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, 537-543. Abstract: http://www.ncbi.nlm.nih.gov/nlmcatalog/9002563
Web page last updated on: August 11, 2014