Endocrine Abstracts

Parathyroid carcinoma is an uncommon cause of PTH-dependent hypercalcemia. The clinical features of parathyroid carcinoma are due primarily to the effects of excessive secretion of PTH. Thus, signs and symptoms of hypercalcemia often dominate the clinical picture. The therapeutic goal at this point is to control the hypercalcemia. We describe two cases of parathyroid carcinoma, effectively treated with calcimimetic Cinacalcet (Mimpara®), the first of a new class of compounds with activity at the calcium-sensing receptor: 55-years old women with parathyroid carcinoma, and with persistent hypercalcemia after four consecutive surgical attempts with wide excision of the involved area, and 53–yr-old man presented with diffuse lytic changes in the bones and a tumor in mediastinum (eventually diagnosed as parathyroid carcinoma). In both cases severe hypercalcemia (ranged 15–17 mg/dL) and high levels of intact PTH (1176 pg/mL and 546 pg/mL respectively) had been found. Symptomatic treatment: hydratation with iv sodium chloride and iv pamidronate and zolendronante had been installed, however without effects, and eventually cinacalcet, 60–90 mg/day, orally, has been used to treat. After first week of the treatment, in both cases calcium and PTH significantly decreased (to 10.8–11.3 mg/dL and 332–113 pg/mL respectively).Cinacalcet appears to have been more effective at controlling hypercalcemia than bisphosphonates in patients with parathyroid carcinoma.