Pattern of bone destruction
Geographic
- narrow transition from normal to abnormal bone
- margin of the lesion is well defined and easily separated from surrounding bone
- least aggressive
- usually indicative of slow growing lesions / benign tumours
Moth-eaten
- wider zone of transition from normal to abnormal
- less well defined lesional margin
- more aggressive
- characteristic of more rapidly growing lesion / malignant bone tumours & osteomyelitis
Permeative
- wide zone of transition
- lesion is poorly demarcated
- not easily separated from surrounding normal bone
- aggressive bone lesion with rapid growth potential
- malignant tumours such as Ewing's
Visible tumour matrix
Calcification
- chondromas, chondroblastoma, chondrosarcoma, chondromyxoid fibroma
- synovial sarcoma
Osteoid
- osteosarcomas, ossifying fibromas, osteomas, osteoblastomas
Ground Glass
- fibrous dysplasia
Cortical erosion
Enchondroma / chondrosarcoma
- can lead to endosteal scalloping & new periosteal bone may be laid down
ABC
- can expand the cortex rapidly
Malignant tumours
- can expand through cortex and lift periosteum
Periosteal response
Periosteal reaction
- slow growing tumour can evoke a periosteal response
- can get buttress at junction of normal & expanded bone
Onion skin pattern
- Ewing's
- multiple layers of periosteal new bone formation
Codman's triangle
- OS, Ewing's, infection
- lifting of periosteum at edge of lesion with bone formation
Sunburst pattern
- OS
- rays of periosteal bone formation radiating away from the bone
Hair on end
- Periosteal osteosarcoma
Soft Tissue Mass
Primary malignant bone neoplasm
Metastasis
Infection