A 15-year-old girl presented with anterolateral knee pain for 6 months. There were tenderness and pain at the anterolateral triangulation of the knee joint. Magnetic resonance imaging revealed a tumor in the anterolateral corner of the knee joint. Arthroscopy did not show the tumor because it was located in fat pad. The tumor was found during fat pad shaving and was resected arthroscopically. Synovial hemangioma was demonstrated histologically. The patient is asymptomatic postoperatively.