PT - JOURNAL ARTICLE AU - Muhammad Nouman Baig AU - Sandra O’Malley AU - Christopher Fenelon AU - Ken Kaar TI - Osteochondroma of acromioclavicular joint AID - 10.1136/bcr-2019-230246 DP - 2019 Aug 01 TA - BMJ Case Reports PG - e230246 VI - 12 IP - 8 4099 - http://casereports.bmj.com/content/12/8/e230246.short 4100 - http://casereports.bmj.com/content/12/8/e230246.full SO - BMJ Case Reports2019 Aug 01; 12 AB - Osteochondroma is the most common type of benign bone tumour. It is a benign chondrogenic lesion derived from aberrant cartilage from the perichondral ring, and it commonly presents in the proximal humerus, proximal femur and knee. Osteochondroma is usually solitary but can be multiple with patients with hereditary multiple exostoses. Malignant changes happen in approximately 1% of cases. Osteochondroma usually causes local pain or swelling. We discuss a unique case of an osteochondroma that highlights the fact that osteochondroma can occur in the most unlikely places, and they should be properly visualised via radiography to evaluate any extensions and compromised surrounding structures before surgical intervention.