Osteochondroma and secondary synovial osteochondromatosis.

Secondary synovial osteochondromatosis (SOC) is a rare disorder caused by a variety of joint disorders. Two unusual cases of secondary SOC are presented. The first patient is a 43-year-old man with extensive SOC developing within a bursa surrounding an osteochondroma of the pubic bone. The second patient is a 23-year-old man who developed florid and progressive SOC of his hip joint following excision of a femoral neck osteochondroma. SOC recurred despite three excisions over a 15-month period. Imaging was useful in pre-operative diagnosis of bursal SOC in the first patient and in detecting multiple recurrences in the second patient. Both cases illustrate prominent SOC developing secondary to osteochondroma. The different hypotheses regarding bursal and secondary SOC are reviewed.