Localized and diffuse forms of tenosynovial giant cell tumor (formerly giant cell tumor of the tendon sheath and pigmented villonodular synovitis).

Tenosynovial giant cell tumor (TSGCT) is a rare benign tumor arising from joint synovia, bursae and tendon sheaths. Their variable clinical presentation is related to variations in site and progression. Localized forms are most frequent in the hands, and diffuse forms in the knee. MRI is necessary and sometimes sufficient for diagnosis. Treatment strategy is guided by progression, symptomatology, location and diathesis. Optimally complete resection is the principle of first-line treatment. Radiation therapy is effective and targeted therapies are promising; both should especially be considered in case of relapse.