Parathyroid carcinoma: features and difficulties in diagnosis and management.

The objective of this review was to study the clinical course and the applicable diagnostic criteria in 12 patients with functioning parathyroid carcinoma, two patients with nonfunctioning parathyroid carcinoma, and a fifteenth patient who had an atypical intrathyroid tumor. The biologic patterns fell into four groups. The patients with functioning parathyroid carcinoma had either a prolonged tumor existence punctuated by hypercalcemic episodes ameliorated by operation to remove the tumor or an aggressive course with widespread metastases. The nonfunctioning cancers were aggressive cancers. The fourth group had one patient (others could have been considered) in whom a definitive diagnosis could not be made. The initial recognition of this cancer is sometimes difficult because consistent diagnostic features, either clinically or pathologically, are lacking. Enbloc resection at the first operation remains the best chance for cure. Surgical resection of recurrent disease appears to be the most effective palliative approach. Death results from hypercalcemia rather than from organ replacement by tumor.