Endocrine System

Parathyroid Gland - Syncytial Giant Cell

Narrative
Comment:
Multinucleated syncytial cells occur in the parathyroid of rats. Their number varies, but these giant cells may occupy up to one-half of the gland. They are formed by cytoplasmic fusion of adjacent chief cells. The cytoplasm may be densely eosinophilic. Syncytial giant cells are not believed to interfere with parathyroid function. There is no consensus that this is an antemortem change. Some scientists consider this a postmortem artifact.
Recommendations:
Diagnosis of syncytial giant cell formation in the parathyroid is recommended. A severity grade is not needed. If both parathyroids are involved, the diagnosis should be qualified as bilateral.
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

Greaves P. 2007. Histopathology of Preclinical Toxicity Studies: Interpretation and Relevance in Drug Safety Evaluation, 3rd ed. Academic Press, Amsterdam, 839-842.

Abstract: http://www.sciencedirect.com/science/book/9780444527714

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
  • Image of syncytial giant cell in the parathyroid gland from a male F344/N rat in a subchronic study

    Parathyroid Gland - Syncytial giant cell in a male F344/N rat from a subchronic study. A syncytial cell formed by fusion of adjacent chief cells is recognized by multiple nuclei and eosinophilic cytoplasm (arrow).

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Parathyroid Gland - Syncytial giant cell in a male F344/N rat from a subchronic study. A syncytial cell formed by fusion of adjacent chief cells is recognized by multiple nuclei and eosinophilic cytoplasm (arrow).
Parathyroid Gland - Syncytial giant cell in a male F344/N rat from a subchronic study. A syncytial cell formed by fusion of adjacent chief cells is recognized by multiple nuclei and eosinophilic cytoplasm (arrow).
Parathyroid Gland - Syncytial giant cell in a male F344/N rat from a subchronic study. Higher magnification of Figure 1 showing the multinucleated syncytial cell with eosinophilic cytoplasm formed by fusion of adjacent chief cells (arrow).
Parathyroid Gland - Syncytial giant cell in a male F344/N rat from a subchronic study. Higher magnification of Figure 1 showing the multinucleated syncytial cell with eosinophilic cytoplasm formed by fusion of adjacent chief cells (arrow).

Authors

Robert R. Maronpot, DVM, MS, MPH, DACVP, DABT, FIATP
Senior Pathologist
Experimental Pathology Laboratories, Inc.
Research Triangle Park, NC

Georgette D. Hill, D.V.M., Ph.D.
Toxicologic Pathologist/Assistant Pathology Program Manager
Comparative Molecular Pathology Division
Integrated Laboratory Systems, Inc.
Research Triangle Park, NC

Reviewers

Thomas J. Rosol, DVM, PhD, DACVP
Professor of Veterinary Biosciences
Senior Advisor, Life Sciences, Technology Commercialization and Knowledge Transfer
The Ohio State University
Columbus, OH

Amy Brix, DVM, PhD, DACVP
Senior Pathologist
Experimental Pathology Laboratories, Inc.
Research Triangle Park, NC