Intra-articular hemangioma of the knee.

Intra-articular hemangioma of the knee is a rare cause of pain and spontaneous hemarthrosis, often seen as an internal derangement of the joint in children and young adults. The tumor is observed in two different forms: the synovial hemangioma or the arteriovenous malformation named also as hemangiohamartomas. They may cause hemorrhagic synovitis and arthropathy, probably as a result of recurrent episodes of intra-articular bleeding and mechanical irritation. Four cases of intra-articular hemangioma of the knee are presented in this study. Two of our cases were diagnosed as synovial hemangioma with the lesions localized inside the knee and the other 2 were intermediate type with the tumor extending to the muscle group and the skin. After magnetic resonance imaging and angiographic assessment, arthroscopic excision was performed in the localized type of the tumor. The other 2 cases received only diagnostic arthroscopy and biopsy followed by conservative treatment due to the extensive localization of the tumors and the serious chondral lesions. The decision of the treatment modality is very difficult in intra-articular hemangioma of the knee because, when combined with chondral degeneration, the incidence of local recurrence is high.