Osteochondroma is a common tumor of the bone and can be complicated by adventitial bursa formation and malignant transformation of the cartilaginous cap. Synovial chondromatosis formation within these bursae is extremely rare and can be confused with malignant transformation of the osteochondroma cap to a chondrosarcoma. We describe a case of extra-articular synovial chondromatosis formation several years following osteochondroma resection. Cartilage nodule formation within the bursal synovial lining and proliferation of cartilage debris shed from the cartilaginous cap during surgery or biopsy are potential etiologies of this rare complication of osteochondromas.