Cinacalcet is effective in the treatment of hyperparathyroidism secondary to malignant transformation of autotransplanted parathyroid tissue. A case report.

Calcimimetics are effective in lowering serum parathyroid hormone (PTH) levels in hyperparathyroidism (HPT). However, they failed to reduce PTH levels in the long term in the setting of primary malignant HPT. A haemodialysis patient suffering from severe longstanding secondary HPT underwent total parathyroidectomy with autotransplantation of parathyroid tissue in her left arm. In the following years, she developed a severe HPT sustained by cancerous transformation of the parathyroid transplanted tissue and resistant both to pharmacological and repeated surgical treatments. The calcimimetic 'cinacalcet' was able to effectively reduce serum PTH levels over a 3-year follow-up and to induce disappearance of the neoplastic lesion on radionuclide imaging. Biochemical control of HPT was associated with a remarkable improvement in cardiac function.