Precise localization of phosphaturic mesenchymal tumor causing tumor-induced osteomalacia: the value of dual-tracer imaging with ¹⁸F-FDG and ⁶⁸Ga-DOTATATE PET/CT.

Phosphaturic mesenchymal tumor (PMT) is a rare cause of tumor-induced osteomalacia (TIO), often presenting with nonspecific symptoms and small tumor size, leading to diagnostic challenges. We report a case of a 25-year-old male with progressive generalized bone pain, hypophosphatemia, and elevated alkaline phosphatase, initially misdiagnosed as spondyloarthritis and osteoporosis. Whole-body bone scintigraphy suggested metabolic bone disease. 18F-FDG PET/CT revealed a destructive lesion in the mandible with moderate uptake, whereas ⁶⁸Ga-DOTATATE PET/CT showed high somatostatin receptor expression, accurately localizing the PMT. Serum phosphate levels normalized rapidly after surgical resection. This case highlights the superior diagnostic value of ⁶⁸Ga-DOTATATE PET/CT over 18F-FDG PET/CT in localizing PMT, facilitating targeted treatment and avoiding prolonged morbidity.