Craniofacial tumor-induced osteomalacia: A report of 2 cases and literature review

Objective To deepen the understanding of tumor-induced osteomalacia (TIO) by reporting its cases and reviewing its relative literature. Methods Two middle-aged female cases of craniofacial TIO misdiagnosed as rheumatoid arthritis were reported.Case 1 was manifested as diffuse bone pain and muscle weakness for 4 years with right eye esotropia for 1 month. Case 2 was manifested as progressive bone pain in low back and hip for 2 years. Laboratory biochemical test showed hypophosphatemia and increased excretion of urophosphorus. Radiological examinations revealed an infiltrative tumor mass in right apex partis petrosae ossis temporalis in case 1, and a soft mass in left nasal cavity and ethmoid sinuses in case 2. Results The tumor was completely removed in case 2 and incompletely removed in case 1, which was pathologically diagnosed as a mixed connective tissue variant phosphaturic mesenchymal tumor. Conclusion The diagnosis of TIO including craniofacial TIO can be established by pathology when the patient is manifested as unexplained persistent osteomalacia and treated mainly by surgery.