Parathyroid pathology: hyperparathyroidism and parathyroid tumors.

CONTEXT: Primary hyperparathyroidism is the most common cause of hypercalcemia in the outpatient setting. Parathyroid adenomas are common, unlike other parathyroid tumors. This review presents a brief summary of current updates in parathyroid pathology.

OBJECTIVE

To review parathyroid development and discuss issues in hyperparathyroidism and diagnosis of parathyroid lesions, including the application of immunohistochemistry and molecular biology.

DATA SOURCES: Current texts, PubMed (National Library of Medicine) articles, and Memorial Sloan-Kettering Cancer Center archives.

CONCLUSIONS

Primary hyperparathyroidism is most commonly seen with sporadic adenomas, followed by hyperplasia, multiple adenomas, and carcinoma. Autosomal dominant familial hyperparathyroidism syndromes should be considered in the evaluation of patients with parathyroid lesions, particularly in association with parathyroid carcinoma. While the incidence of parathyroid carcinoma is quite low, it is seen with a greater frequency in those patients with hyperparathyroidism-jaw tumor syndrome. Inactivation of the tumor suppressor gene HRPT2 can be identified in a large number of parathyroid carcinomas. Hence, germline HRPT2 gene mutations may reflect unrecognized syndromic patients.