Tumor‐induced osteomalacia (TIO) is a rare paraneoplastic syndrome, resulting from the secretion of the phosphaturic hormone fibroblast growth factor 23 (FGF23) from a morphologically and genetically distinct tumor of soft tissue and bone, termed a phosphaturic mesenchymal tumor (PMT) (Fig. 1) [1, 2, 3]. The gene discussed is FGF23; the disease is mesenchymal cell neoplasm.