A case of oncogenic osteomalacia detected by 111In-pentetreotide total body scan.

A case of tumor-induced osteomalacia in a 35-year-old woman suffering from severe bone pain and muscle weakness is described. This uncommon disease is characterized by a reduced serum phosphorus level with elevated urinary phosphate excretion, normocalcemia, high serum bone alkaline phosphatase and a deficiency of 1,25 dihydroxyvitamin D3. The tumors responsible for oncogenic osteomalacia are usually small, benign and commonly located in bone or soft tissues of the head and the limbs, so the diagnosis can often be difficult. In this case a 111In-pentetreotide scintigraphy was able to detect a hemangiopericytoma located in the right mascellar sinus. Removal of the tumor resulted in the reversal of clinical and biochemical abnormalities.