Synovial osteochondromatosis in the subacromial bursa

Synovial osteochondromatosis may occur within an otherwise normal synovial joint (primary disease), within a diseased joint (secondary disease), within tendon sheaths, and within extraarticular bursal cavities. Each of these four types of disease can present in one of three progressive morphologic stages in which the intrasynovial proliferations of cartilage and bone break free to form loose bodies. A 61-year-old man presented with loose bodies about his right shoulder. This case report demonstrates that the disease was a true example of bursal osteochondromatosis of the subacromial bursa, Stage III, rather than synovial osteochondromatosis of the shoulder joint. Well-documented cases of bursal osteochondromatosis are rare.