Tumor-induced osteomalacia: a case report.

Tumor-induced osteomalacia (TIO) is a rare paraneoplasic syndrome with overproduction of fibroblast growth factor 23 as a phosphaturic agent, leading to chronic hyperphosphaturia and hypophosphatemia, associated with inappropriately normal or low levels of 1,25-dihydroxyvitamin D. Diagnosis of this disease is often challenging. The following case report described a middle-aged man with symptoms of bone pain and severe muscle weakness, who was found to have TIO.