Tenosynovial giant cell tumor

Definition

A rare soft tissue tumor characterized by lesions predominantly originating from the synovial tissue of joints, tendon sheaths, or bursa. They are typically benign tumors that can either be localized or diffused. Localized tumors are usually painless, firm and slow growing, detected mostly in the fingers and hand (can also be present in wrist, foot or ankle), and patients are asymptomatic. Diffuse-type tumors are more aggressive and often involve large joints (knee, hip, ankle and shoulder). Symptoms may include joint pain, tenderness, swelling, limitation of motion and hemorrhagic joint effusions. Some localized tumors may recur, however they are usually non-destructive. Recurrences are more common in diffused tumors and can lead to joint instability, degenerative joint disease and significant functional impairment. Rare cases with malignant transformation, presenting as aggressive sarcomas leading to local destruction and metastasis to lymph nodes (particularly inguinal and pelvic) and lungs are also reported.