Tumor induced osteomalacia - A long way toward correct diagnosis and management

Tumor-induced osteomalacia (TIO) is an uncommon type of osteomalacia associated with phosphaturic mesenchymal tumors (PMTs). Due to nonspecific symptoms, the diagnosis and appropriate management of the disease is often delayed for many years. Involvement of spine with TIO associated tumors is exceedingly rare. We present a 53-year-old woman with a 10-year history of bone pain, muscle weakness and multiple bone fractures that markedly impaired her quality of life. Biochemical evaluation revealed hypophosphatemia due to renal phosphate wasting and elevated plasma fibroblast growth factor 23 (FGF-23) concentration indicating PMT. It was found using ⁶⁸Ga DOTA TOC PET/CT scan in the vertebral body L2. The patient underwent surgical resection of the tumor. Postoperatively, there was a significant decrease in phosphaturia, normalization of serum phosphate, 1.25 dihydroxyvitamin D and plasma FGF23 concentration. Thereafter the patient's condition markedly improved concerning her motility and basic daily activities. This case report demonstrates the first known case of TIO in the Slovakia and points to a long way from onset of symptoms toward correct diagnosis and successful surgical management.