Introduction:
Benign proliferative disease
Affect joints, bursae, tendon sheaths
Diffuse, less commonly focal
Young to middle aged adults
Most common joint: knee. Other joints include hip, ankle, shoulder
Local recurrence in 50%
Monoarticular, rarely polyarticular
Radiograph:
Normal, may demonstrate soft-tissue swelling
Preservation of joint spaces and mineralization until late
Bone erosions are common especially in hip and ankle
MR:
Lobulated mass of synovium
Hemosiderin gives low signal on all pulse sequences
Areas of high signal on T2 may be seen due to inflamed synovium or joint effusions
References:
Sheldon PJ et al. Imaging of Intraarticular Masses. RadioGraphics 2005;25:105-119
