Metastatic parathyroid carcinoma (mPCa): natural history and treatment of a case.

We report the case of a 46-year-old male patient who, after disease-free intervals of five, four and one and a half years following resection of an 'atypical' parathyroid adenoma in 1982, relapsed with clinical and laboratory recurrence of primary hyperparathyroidism (PHP). Noninvasive, traditional and modern imaging methods localized small distinct metastatic foci in both lungs without evidence of primary thyroid, neck or mediastinal tumor. Three successive bilateral lung nodule excisions resulted in a long PHP remission, while a three month treatment with normal saline infusions, diuretics, calcitonine and pamidronate infusions, following the last recurrence, resulted in moderate improvement of hypercalcemia and hypercalciuria with no effect on both PTH secretion or on the size of new metastatic lung foci. Recurrent mPCa with or without secretion of biologically active PTH is optimally treatable with successive surgical resections of the metastases and intermittent medical treatment to achieve PTH secreting tumor mass reduction and a beneficial metabolic effect.