Phosphaturic mesenchymal tumor: An underdiagnosed rare entity

Tumor-induced osteomalacia is a paraneoplastic syndrome resulting in renal phosphate wasting and decreased bone mineralization. Phosphaturic mesenchymal tumors represent a rare etiology of tumor-induced osteomalacia. They are exceptionally rare, probably accounting for < 0.01% of all soft tissue tumors. Most PMTs present as small inapparent lesions that require very careful clinical examination and radionucleotide scan for localization. Here we describe a case in a 65 years old woman with recurrent multiple bone fractures and subsequent detection of a tumor involving right femur and adjacent soft tissue, low phosphate level and elevated serum Fibroblast growth factor-23 (FGF-23).