Multimodal Functional Imaging in Tumor-induced Osteomalacia: 68Ga-DOTATATE, 18F-FDG, and 68Ga-FAPI PET/CT Findings

Tumor-induced osteomalacia, resulting from tumoral overproduction of fibroblast growth factor 23, is a rare paraneoplastic syndrome clinically characterized by muscle weakness, bone pain, and pathological fractures. Fewer than 1,000 cases have been reported in the literature. Laboratory findings typically include hypophosphatemia, normal or decreased levels of 1.25-dihydroxy vitamin D, and normal or elevated levels of FGF23. Functional imaging methods, particularly somatostatin receptor imaging, play an important role in the localization of the tumor. In this case of tumor-induced osteomalacia, we presented the findings from gallium-68 (⁶⁸Ga)-DOTATATE, ⁶⁸Ga-fibroblast, and ¹⁸F-fluorodeoxyglucose positron emission tomography imaging modalities used for tumor localization.