Asymptomatic synovial chondromatosis of the ankle: an incidental finding.

Synovial chondromatosis is an uncommon, benign lesion of nodular cartilaginous neoplastic development of the synovium that can lead to loose bodies and arthritic degeneration if left untreated. Although very rare, malignant transformation to chondrosarcoma can occur. Primary and secondary forms of synovial chondromatosis also exist, and each has distinct clinical, radiographic, and histologic characteristics. In this article, we describe a case of extensive primary synovial chondromatosis of the ankle that was asymptomatic until just before presentation, and that was treated by means of open synovectomy with excision of the osteochondromatous lesions within the joint.