Osteoid osteoma-this is a small, benign tumor that is very painful, especially at night. the pain is typically relieved only by aspirin. radiographs are distinctive as described. osteochondromas arise from the metaphysis of long bones and present as bony painless mass. ewing sarcoma presents radiographically as periosteal elevation (onion skinning) while osteosarcoma appears as a mixed lytic and blastic star burst process. fibrous dysplasia is characterized by congenital fibrous replacement of cancellous bone.
board testing point: recognize the typical historical and radiographic findings associated with an osteoid osteoma, which may be easily confused with a neoplastic lesion.