Parathyroid carcinoma with postoperative prolonged hypocalcemia in a patient with chronic renal failure.

Parathyroid carcinoma is a rare disease that usually presents with severe hypercalcemia and marked elevation of parathyroid hormone level. A 64-year-old male patient with repeated episodes of renal stones sustained chronic renal failure. Subsequently, he developed acute uremic symptoms and underwent a left upper parathyroidectomy. Parathyroid carcinoma was diagnosed after surgery. Asymptomatic hypocalcemia was the initial presentation. Protracted symptomatic hypocalcemia developed 8 months postoperatively, accompanied by an extremely high parathyroid hormone level. Delayed "bone hunger" syndrome concomitant with down-regulation of the parathyroid hormone receptors or production of parathyroid hormone with diminished bioactivity may have been the possible causes.