18 F-FDG PET/CT in a Giant Cell Tumor of Bone Masquerading as a Retroperitoneal Soft Tissue Sarcoma

Giant cell tumor of bone (GCTB) is a rare, benign but locally aggressive neoplasm that typically arises in the epiphysis of long bones. GCTB occurrence in the axial skeleton is less common. Due to its variable radiological appearance and unusual location, GCTB can be misdiagnosed as a soft tissue or retroperitoneal mass, leading to delays in diagnosis and inappropriate treatment. We present the case of a 36-year-old woman who was misdiagnosed as a case of spinal tuberculosis and was started on ATT. Initial imaging, including ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI), revealed a large, retroperitoneal mass involving the L2 vertebral body, raising suspicion of a malignant soft tissue tumor. Further evaluation with 18 F-FDG PET/CT suggested a retroperitoneal metabolically active lesion, reinforcing the need for histopathological confirmation.