Hypophosphatemic osteomalacia secondary to jaw phosphaturic mesenchymal tumor: a case report with literature review.

Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome characterized by renal phosphate wasting, resulting in hypophosphatemia and altered bone turnover. It is most frequently caused by phosphaturic mesenchymal tumors (PMTs), a rare and distinct group of neoplasms. Patients with TIO exhibit clinical features of osteomalacia, including bone and muscle pain, severe muscle weakness, gait disturbance, and increased susceptibility to fracture. PMTs exhibit pananatomic distribution, in soft tissue or bones, but are most commonly found in the lower extremities, followed by the head and neck. Most head and neck tumors are located in the sinus area, while jaw involvement is exceptionally rare. Diagnosis is difficult and the misdiagnosis rate is high. A case PMT occurring in the jaws are presented to highlight diagnostic features and challenges. Notably, PMTs are benign tumors and their removal results in correction of the biochemical aberrations that underly the TIO.