4-year-old female with persistent synovitis with thickening on ultrasound of the right knee, evaluate for tumor or PVNS. MENISCI AND LIGAMENTS: The medial and lateral menisci are intact. Anterior cruciate ligament, posterior cruciate ligament, and lateral collateral ligaments are intact.BONE AND MARROW: The bones demonstrate normal intensity.SYNOVIUM: Multiple intra-articular synovial based nodules are best visualized on image 8 of series 601. No significant erosions are identified. There is diffuse enhancement and thickening of the synovium.MUSCULATURE: Musculature are normal in appearance.ADDITIONAL
Large joint effusion, multiple intra-articular synovial based nodules, and diffuse thickening and enhancement of the synovium most suggestive of pigmented villonodular synovitis. 