A Case of Tumor-Induced Osteomalacia Detected by Venous Sampling.

Tumor-induced osteomalacia (TIO) can cause osteomalacia due to excessive production of fibroblast growth factor 23 (FGF23) by the tumor. Since TIO is a very rare disease, it is often misdiagnosed as intervertebral disc herniation, spondyloarthritis, or osteoporosis. We report a 65-year-old man who developed generalized arthralgia and difficulty walking two years ago and was diagnosed with multiple fractures throughout his body.