Extraarticular extrasynovial solitary osteochondromatosis of the ankle: A rare case report and review of literature

INTRODUCTION: Synovial chondromatosis (SC) is a relatively common benign condition of the synovial joint characterized by the formation of cartilaginous nodules in synovium. However, extra articular osteochondromatosis is rare and only few have been reported around the ankle joint. We have reported such a presentation and have reviewed the literature extensively. PRESENTATION OF CASE: We present a 26 year old male patient with a painless swelling over the lateral aspect of his left ankle. He was subjected to clinical and radiological examination which revealed a firm to hard swelling around the lateral malleolus and a lobulated juxtacortical cystic lesion with calcification. He underwent a surgical excision and subsequent histopathology was suggestive of SC. DISCUSSION: The subtle clinical and radiological presentation of SC can lead to both a delay in the diagnosis and a diagnostic dilemma if suspicion is low. Early meticulous diagnosis and management can curtail morbidity. CONCLUSION: The degree of suspicion needs to be high to diagnose the condition early to prevent both morbidity and inadequate treatment. Histopathological corroboration is needed to rule out uncommon but possible malignant transformation, notably in long standing cases. (C) 2020 The Author(s). Published by Elsevier Ltd on behalf of IJS Publishing Group Ltd.