Thus, acquired cases of FGF23-related hypophosphatemic osteomalacia without iron infusion therapy were presumed to be TIO with FGF23 producing tumors mainly in the bone or soft tissue, defined as phosphaturic mesenchymal tumors (PMTs) (Folpe, 2019; Folpe et al., 2004). The gene discussed is FGF23; the disease is mesenchymal cell neoplasm.