Successful use of cinacalcet HCl in a patient with end-stage renal failure and refractory secondary hyperparathyroidism due to parathyromatosis

We present the case of a 65-year-old male on long-term dialysis for end-stage renal failure, who developed persistent secondary hyperparathyroidism after subtotal parathyroidectomy, which proved refractory to treatment. Parathyromatosis, a rare cause of recurrent hyperparathyroidism, which may develop when tissue seeded into the neck during subtotal or total parathyroidectomy becomes hyperfunctioning [Maxwell and Winearls 1997], was diagnosed. The patient had excessively high levels of circulating parathyroid hormone (PTH), elevated serum calcium and deteriorating cardiovascular status. Repeated surgery and treatment with high-dose vitamin D failed to provide a sustained decrease in serum PTH levels. Administration of cinacalcet HCl, a second generation calcimimetic, at doses of 30 - 180 mg/day provided a gradual and sustained suppression of PTH (> 1,700 - 344 ng/l) without increasing the calcium-phosphate product.