A rare case of a huge diffuse-type tenosynovial giant cell tumor in the ankle

Tenosynovial giant cell tumor (TSGCT) is a rare tumor originating from the synovial lining of joints, tendon sheaths, and bursae. It is categorized into localized and diffuse types. The diffuse-type TSGCT (D-TSGCT), formerly called pigmented villonodular synovitis, although benign, can be locally aggressive. Magnetic resonance imaging is the modality of choice for diagnosing and assessing the severity of the disease. The lesions demonstrate characteristic “blooming” on gradient echo sequences. Histopathology reveals villous, nodular, or villonodular components and hemosiderin deposition. Here, we report the case of a 28-year-old man with a huge D-TSGCT in the left ankle.