At the junction between cartilage cap and the bony stalk of osteochondroma, it is not uncommon to see islands of cartilage embedded within the underlying cancellous bone. This should not be mistaken as a sign of malignancy. Malignant transformation (almost always to a chondrosarcoma) is seen in only about 1% of osteochondromas. Many osteochondromas are left alone. Removal is indicated for pain, disability, suspicious changes on imaging studies (when chondrosarcoma cannot be ruled out), abnormal increase in size, or for cosmetic reasons.