Oncogenic osteomalacia from pterygopalatine fossa mass

Oncogenic osteomalacia, or tumour-induced osteomalacia, is an uncommon cause of osteomalacia. It has been reported to occur in patients with hypophosphataemia due to excess renal phosphate excretion secondary to mesenchymal tumours. Occurrence of this pathological process in the head and neck is extremely rare. Case report and literature review. We present a case of a 73-year-old woman with tumour-induced osteomalacia. She was initially followed by the endocrinologists for osteomalacia and pathological fractures. An indium-111 pentetreotide scan showed activity in the left pterygopalatine fossa. A mass was endoscopically resected, and the histopathological appearance was consistent with a haemangiopericytoma. Following surgery, the patient's hypophosphataemia and vitamin D deficiency corrected and her symptoms resolved. Oncogenic osteomalacia, or tumour-induced osteomalacia, is a rare entity in the head and neck. Current research is elucidating the mechanism by which phosphaturic wasting occurs. In most patients, symptoms resolve once the offending tumour is removed.