Giant Cell Tumor of Tendon Sheath Revealed on 68Ga-DOTA-TATE PET/CT in a Patient With Suspicious Tumor-Induced Osteomalacia.

Giant cell tumor of tendon sheath (GCTTS) is benign mesenchymal neoplasm, and it rarely induces hypophosphatemia. We report a 49-year-old woman with suspicious tumor-induced osteomalacia underwent Ga-DOTA-TATE PET/CT to identify potential causative tumor, which showed a hypermetabolic soft tissue nodule in the right foot. Pathology confirmed it as GCTTS following surgical resection. The patient's symptoms improved rapidly, and the serum phosphate normalized after surgery, which supports the diagnosis of tumor-induced osteomalacia. Our case showed GCTTS can be rich of somatostatin receptor and cause osteomalacia.