Primary synovial osteochondromatosis of the ankle.

To cite: Ozyurek S, Atik A, Sivrioglu AK, et al. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2013009046 DESCRIPTION A 35-year-old man presented with an 18-month history of chronic left ankle pain and swelling. The pain was a dull ache and present throughout the day. On examination, there was swelling of the left ankle, more anteriorly, with palpable loose bodies. There was associated terminal restriction of motion. Radiographs of the left ankle revealed multiple subcentimeter osseous structures in the anterior of the tibiotalar joint (figure 1A). Sagittal T1-weighted MRI showed multiple subcentimeter hypointense structures in the same localisation as determined on the ankle radiographs (figure 1B). Imaging confirmed the diagnosis of primary synovial osteochondromatosis of the left ankle. He was treated by open excision of the osteochondromatous lesions within the joint (figure 2A,B). Primary synovial osteochondromatosis is an uncommon generally benign disorder characterised by formation of cartilaginous bodies within the synovia of the different joints, tendon sheaths and bursae. Although the aetiology is unknown, there are data suggesting neoplastic origin with chromosome 6 abnormalities. It most commonly involves large joints such as the knee, hip and elbow. Depending on the location, there can be little restriction on the range of motion, which could allow significant growth of the cartilaginous bodies and thus delayed diagnosis of osteochondromatosis. The diagnosis of synovial osteochondromatosis is commonly made following a thorough history, physical examination and radiological examination. Since this condition tends to be progressive but self-limiting, indications for surgery depend on the