We report a case of phosphaturic mesenchymal tumor arising in the nasal cavity. The patient was a 38-year-old man who presented to his previous doctor with a 3-year history of progressively worsening bone pain. Laboratory examination revealed high blood levels of fibroblast growth factor-23 (FGF23), and the patient was referred to our hospital for further investigation and treatment. Based on our examination findings, we suspected tumor-induced osteomalacia. Systemic venous sampling for FGF23 and 68Ga-DOTATOC-PET revealed a tumor in the right nasal cavity as the lesion causing the osteomalacia. Complete removal of the tumor resulted in normalization of the blood FGF23 levels and dramatic improvement of the symptoms.
