U.S. flag

An official website of the United States government

Dot gov

The .gov means it's official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Skip to Main Navigation
Skip to Page Content
Skip to Atlas Navigation

Parathyroid Gland - Hyperplasia, Focal

Image of hyperplasia, focal in the parathyroid gland from a male F344/N rat in a chronic study
Parathyroid Gland - Hyperplasia, Focal in a male F344/N rat from a chronic study. This low-magnification photomicrograph contains a focus of hyperplasia (arrow) with a growth pattern distinct from the adjacent parathyroid parenchyma.
Figure 1 of 4
Image of hyperplasia, focal in the parathyroid gland from a male F344/N rat in a chronic study
Parathyroid Gland - Hyperplasia, Focal in a male F344/N rat from a chronic study. Focal hyperplasia is characterized by cells with rounded nuclei and abundant hypertrophic cytoplasm but without compression of adjacent parathyroid parenchyma.
Figure 2 of 4
Image of hyperplasia, focal in the parathyroid gland from a male Wistar Han rat in a chronic study
Parathyroid Gland - Hyperplasia, Focal in a male Wistar Han rat from a chronic study. Two focal areas of hyperplasia with pale, enlarged cells (compared with surrounding parathyroid parenchyma) are present.
Figure 3 of 4
Image of hyperplasia, focal in the parathyroid gland from a male F344/N rat in a chronic study
Parathyroid Gland - Hyperplasia, Focal in a male F344/N rat from a chronic study. Two to three adjacent nests of hyperplastic foci are present; the pale staining of their hypertrophic cells makes them stand out from the normal parathyroid tissue.
Figure 4 of 4
next arrow

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