SPR Unknown # 69 -- FINAL

Chun Feng, MD

Eugene Anandapa, MD

Children's Memorial Hospital


11 year old female with left knee swelling


Pigmented villonodular synovitis, synovium, joint effusion, MRI, plain film, 1093

Publication Date: 2006-01-09


11 year old female with left knee swelling


Plain film: a suprapatellar soft tissue mass seen on AP and lateral views in the location of the joint space. No evidence of abnormal calcification.

MR: multiloculated cystic lesion originating from the joint space of the left knee and extending around the distal left femur with a solid deeper,inferior component which enhances and appears synovial based.


The differential should include joint based masses such as pigmented villonodular synovitis, synovial chondromatosis, tuberculous arthritis, synovial haemangiomatosis, hemophilic arthropathy, rheumatoid arthritis and synovial sarcoma.


PVNS is a chronic proliferative disorder in the synovia of the joints, bursae, and tendons. There are two forms of PVNS: the diffuse form affects the entire synovial membrane of a joint or bursa, and the localized form affects tendon sheaths or a portion of the synovium.

PVNS typically occurs in young adults, commonly during the third or fourth decade of life. The knee is the most common site of involvement, but any articulation can be affected . PVNS is usually monoarticular, but bilateral and even symmetric involvement has been reported. Males are affected more than females, and history of trauma is evident in approximately 50 percent of cases.

PVNS commonly presents in young adults with slowly progressive intermittent pain and swelling of the joint. Brown effusion is sometimes present due to the presence of hemorrhagic or serosanguinous fluid in the affected joint, with no history of antecedent trauma. Surgical removal of the synovium is the treatment of choice for aggressive PVNS.

Plain films demonstrate joint swelling with lobular soft-tissue masses or a joint effusion, preservation of joint space, and the absence of osteoporosis. Bone erosions and subchondral cysts may or may not be present.

MR shows the synovium as intermediate in signal intensity on T1 weighted images and as interspersed areas of increased and decreased signal intensity on T2 weighted images. Regions of low signal intensity on both T1- and T2-weighted spin echo images, especially on gradient echo MR images, may be seen due to the deposition of hemosiderin. Increased T2 signal intensity is indicative of joint fluid and inflamed synovium. MR imaging may also reveal extensive cystic changes within the bones.


  1. Greenfield, G.B. Radiology of Bone Diseases 5th ed. Philadelphia: W.B. Saunders, 1990: 961-2.
  2. Resnick, D. Diagnosis of Bone and Joint Disorders 4th ed. Philadelphia: W.B. Saunders, 2002: 4241-50.

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