Bone tumour. Light micrograph of a section through a chondroma, a non-cancerous tumour of cartilage. Cartilage is the tough, elastic tissue that makes up part of the skeleton. Chondromas can occur in the bones of the hands, feet, legs and arms, or in ribs. They sometimes cause problems such as pain or swelling. They may weaken bones and make them more likely to fracture. Although they normally stop growing when the rest of the bones do, they sometimes continue to grow into adulthood. In this case, they could give rise to cancer (chondrosarcoma). Although most chondromas do not cause symptoms, they can be surgically removed if necessary. Magnification unknown.