A Man With Persistent, Enigmatic Bone Pain and Hypophosphatemia

摘要

Oncogenic osteomalacia is a rare metabolic bone disorder characterized by hypophosphatemia, hyperphosphaturia, and low or inappropriately normal 1,25-dihydroxyvitamin D level. It is caused by phosphaturic factors secreted by mesenchymal tumors. Removal of these tumors can result in cure of the condition. However, the diagnosis is often delayed for months to years due to insufficient recognition of this disorder. One of the earliest clues to this diagnosis is the presence of hypophosphatemia. However, this may be ignored by the unsuspecting clinician. We report a case of a man who presented with persistent pain in his knees, hips, and back. The diagnosis was delayed for 18 months, resulting in progression of disability to the point of difficulty with ambulation. Laboratory studies revealed hypophosphatemia. Following recognition of the disorder, the causative tumor was found in the right middle turbinate. Removal of the tumor resulted in complete recovery. The differential diagnosis, diagnostic evaluation, localization of tumor, and treatments are discussed.