CASE 107
By: Dr. Nizar Al-Nakshabandi MD, FRCPC
HISTORY: 50-year-old male with left hip pain.
What are your findings?
What is the differential diagnosis?
What are the causes?
FINDINGS:
The AP radiograph of the pelvis [A] demonstrates well ossified numerous lesions projected over the left hip joint. The left hip demonstrates concentric narrowing with subchondral sclerosis secondary to osteoarthritic changes.
Axial non-contrast CT scan through the left hip [B] demonstrates and confirms these loose ossified bodies inside the left hip joint. Furthermore, it confirms the concentric narrowing of the left hip.
DIFFERENTIAL DIAGNOSIS:
· Primary Synovial osteochondromatosis.
· Secondary synovial chondromatosis.
· Calcified hemangioma.
· Pigmented villonodular synovitis.
· Lipoma arborescens.
· Synovial chondrosarcoma.
DIAGNOSIS:
Primary synovial osteochondromatosis.
PEARLS AND DISCUSSION:
Synovial osteochondromatosis is a benign monoarticular arthropathy. It is thought to be related to synovial metaplasia which results in intra-articular ossified loose bodies. With the causes unknown, it is termed primary synovial osteochondromatosis. When it is a result of degenerative disease, it is then given the name secondary synovial osteochondromatosis. Most cases involve the knee followed by the hip, elbow and shoulder.
This benign disease goes through 3 phases, the first of which is metaplastic formation of cartilaginous nodules, transitional zone occurs within these nodules which detach and become into free intra-articular bodies. Followed by the last phase which is the resolution of the synovial proliferation but persistence of the loose bodies.
The plain radiograph and CT appearances are described in the above case. MRI depends on the level of synovial activity and loose body formation. Gradient echo images will show blooming artifact.
These cases are treated by synovectomy or removal of intra-articular bodies.
FURTHER READING:
1. Kenan S, Abdelwahab IF, Klein MJ et-al. Case report 817: Synovial chondrosarcoma secondary to synovial chondromatosis. Skeletal Radiol. 1993;22 (8): 623-6.
2. Murphey MD, Vidal JA, Fanburg-smith JC et-al. Imaging of synovial chondromatosis with radiologic-pathologic correlation. Radiographics. 27 (5): 1465-88
3. N.A Al-Nakshabandi, A.G Ryan, H Choudur, Torreggiani W, Nicoloau S, Munk PL, Al-Ismail K.. Pigmented villonodular synovitis. Clin Radiol. 2004 May;59(5):414-20.
