Osteosarcoma
- Highest risk during adolescent growth spurt
- Twice as common as Ewing Sarcoma
- Increased incidence with hereditary retinoblastoma
- Found in Li-Fraumeni syndrome (mutation in p53 gene)
- Secondary tumor from radiation therapy
Clinical Presentation
- Painful or painless, hard, and enlarging extremity mass.
- Pathologic fractures
- Which part of the bone & which bones?
- Metaphyses of long bones
- Distal femur>proximal tibia> proximal humerus
- Usually multicentric
- Metastasis to lungs (most common), bones
Imaging
- X-ray
- Destructive lesion, cortical breakthrough with soft tissue extension
- “Sunburst” appearance
- Skipped lesions
- Osteolytic or osteoblastic lesions
- CT to define bony extent
- MRI superior to define extent of marrow and soft tissue involvement
Treatment
- Surgical excision (usually amputation)
- Chemotherapy
- Less responsive to radiotherapy than Ewing’s
Prognosis
- 75% cure with nonmetastatic
- 20-30% cure with pulmonary mets (pulmonary nodules need to be resected)
Osteosarcoma -- Ewing's
- Age: 2nd decade -- 2nd decade
- Associations: Rb, Li-Fraumeni, radiotherapy -- none known
- Site of presentation: metaphyses of long bone -- diaphyses of long bone
- X-ray pattern from extension into soft tissue: starburst -- onion-skinning
CHLA Board Review 2005