- Highly malignant primary bone tumor
- Most frequent in children and adolescents aged 4-15 years and rarely develops in adults older than 30 years.
- Ewing sarcoma is the second most common malignant bone tumor in young patients, and it is the most lethal bone tumor.
- Males are affected more frequently than females (approximately 1.5:1).
 Imaging Findings
 Plain films
- Both long and flat bones are affected.
- In the long bones, the tumor is almost always metaphyseal or diaphyseal.
- Most commonly, radiographs show a long, permeative lytic lesion in the metadiaphysis and diaphysis of the bone with a prominent soft tissue mass extending from the bone.
- Periosteal reaction usually is present, and it often has an onionskin or sunburst pattern, which indicates an aggressive process.
- In some patients, Codman triangles may be present at the margins of the lesion. These result from the elevation of the periosteum and central destruction of the periosteal reaction caused by the tumor.
Patient #1: Radiograph demonstrates classic sunburst pattern of periosteal reaction.
 See Also
 External Links
- Strauss LG. E-medicine rads article