Arthroscopic treatment of tumor-like lesions of the knee joint: Localized pigmented villonodular synovitis and ganglion cyst of the anterior cruciate ligament.

We present the arthroscopic treatment of a case of localized pigmented villonodular synovitis that led to increasing restriction of knee flexion and the case of a ganglion cyst within the anterior cruciate ligament causing unspecific pain. Both pathologies could be resected arthroscopically with complete relief of symptoms and no recurrence. In cases with unspecific clinical signs and intra-articular masses shown on magnetic resonance imaging, arthroscopy is the next therapeutic step. Localized tumor-like lesions can often be excised without recurrence in the same session.