Hypercalcemia in malignant paraganglioma due to parathyroid hormone-related protein

A 15-year-old boy had hypercalcemia in association with malignant retroperi toneal paraganglioma. He had suppressed circulating levels of intact parath yroid hormone, whereas parathyroid hormone-related protein (PTHrP) immunore activity was elevated in plasma. Both the serum 25-hydroxyvitamin D and 1,2 5-dihydroxyvitamin D levels were normal. Preoperatively the patient require d control of hypercalcemia with intravenous pamidronate therapy. His circul ating calcium and PTHrP concentrations became normal after a successful sur gical resection of the primary retroperitoneal tumor. To our knowledge, thi s is the first reported case of elevated PtHrP levels in a patient with par aganglioma which resolved postoperatively.