[Synovial giant cell tumor or nodular circumscribed form of pigmented villonodular synovitis?].

In two case reports we demonstrate symptoms, clinical findings and treatment of patients with a benign synovial giant cell tumor of the knee and ankle joint. This tumor impresses like a localized pigmented villonodular synovitis but compared to this benign synovial giant cell tumors are rare in synovial joints and more often localized at the synovial tendon sheaths of fingers. Symptoms and clinical findings often mimic meniscal lesions. One of the most important finding is a hemorrhagic joint effusion without previous trauma. There are no typical findings in diagnostic imaging procedures and it seems that the most important fact is that the clinician is aware of this type of synovial tumor. Early resection of the tumor within wide margins is the treatment of choice. Postoperative radiotherapy is not to recommend.