Parathyroid Carcinoma

PARATHYROID CARCINOMA IS a rare endocrine malignancy. It accounts for <1% of cases of sporadic primary hyperparathyroidism (PHPT) and is usually associated with more severe clinical manifestations than its much more common benign counterpart, parathyroid adenoma. Its course is typically indolent but progressive. The diagnosis of malignancy is often made only when local recurrence or metastases occur, because the histology of parathyroid tumors can be equivocal or frankly misleading. Most patients with recurrent disease ultimately succumb to the effects of hypercalcemia rather than to direct tumor invasion or distant metastases. A complete resection of all malignant tissue at the time of initial surgery allows for the greatest likelihood of a cure. Clinical clues to the possibility of a parathyroid cancer, therefore, should lead the surgeon to an aggressive initial operative approach. In the last decade, greater knowledge of the molecular pathogenesis of parathyroid carcinoma has led to the development of diagnostic markers that show promise, particularly when the histology is ambiguous. Moreover, there is hope that greater understanding of the pathogenesis of parathyroid cancer will lead to the development of new therapeutic strategies for advanced, inoperable disease. This review focuses on the more recent advances in parathyroid carcinoma, particularly its molecular pathogenesis, diagnosis, and management.