Parathyroid carcinoma: sixteen new cases and suggestions for correct management.

We undertook a retrospective study in 16 patients with parathyroid carcinoma, with the aim of conveying experience from management of this rare cause of hyperparathyroidism (HPT). From 1980 to 1996 we operated on 309 patients with HPT, 290 of whom had primary HPT, and parathyroid carcinoma was diagnosed in 16 (5.2%) cases. In none was the malignancy diagnosed preoperatively. The average serum calcium and parathyroid hormone levels were significantly higher (p < 0.05) than in patients with parathyroid adenoma, and the mean tumor size was 2.9 cm (median 2.5 cm, range 1.5-4.5 cm). Twenty-eight operations were performed with resulting normalization of serum calcium levels for more than 6 months in 11 patients. Six patients presented prolonged postoperative hypocalcemia (2-10 months), and five patients had persistent HPT. Ten patients experienced recurrent disease; the median disease-free period was 24 months (range 4-72 months). None of the patients was treated with chemotherapy, one patient underwent radiation therapy (50 Gy in 25 sessions) but required reoperation for local recurrence 4 months later. Three patients are still alive (two with recurrence). Average survival was 40 months (median 31 months, range 11-131 months).