Clinical characteristics and treatment patterns of tenosynovial giant cell tumor in Japan: an analysis of the Japanese bone and soft tissue tumor registry.

BACKGROUND: Tenosynovial giant cell tumors (TGCT) are rare proliferative disorders arising from the synovium of the joints, tendon sheaths, and bursae. While being generally considered a benign disease, it can cause pain, joint dysfunction, and local recurrence. We investigated TGCT epidemiological characteristics and treatment patterns in Japan using data from the Japanese Bone and Soft Tissue Tumor (BSTT) registry and a nationwide institutional survey. METHODS: A retrospective analysis was performed using the BSTT registry maintained by the Musculoskeletal Tumor Committee of the Japanese Orthopedic Association. Patients diagnosed with TGCT between 2006 and 2019 were included. Demographic characteristics, tumor presentation, diagnostic procedures, and surgical treatments within 1 year of registry entry were analyzed. RESULTS: Overall, 3779 patients with TGCT were identified. The mean age at diagnosis was 44.9 years (range 4-97 years), and 62.1% of patients were women. Most tumors presented as solitary lesions (99.0%). Biopsies were performed in 1148 patients. Surgical treatment within 1 year of registry entry was recorded in 2875 patients (76.1%), while 888 did not undergo surgery and surgical status was unknown in 16. Functional outcome assessments using the International Society of Limb Salvage scores were available for 177 patients. CONCLUSIONS: This study overviews the demographic characteristics and initial treatment patterns of TGCT in Japan. Clinical features are broadly consistent with those reported internationally, and surgery remains the primary management strategy. Longer follow-up and more detailed tumor subtype information are warranted to better characterize the natural history and optimize management strategies.