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Ewing's Sarcoma
Radiologically, Ewing's sarcoma is often associated with a lamellated or "onion skin" periosteal reaction. This appearance is caused by and splitting and thickening of the cortex by tumor cells. The lesion is usually lytic and central. Endosteal scalloping is often present. The "onion-skin" appearance is often followed with a "moth-eaten" or mottled appearance and extension into soft tissue. Bone marrow infiltration is not obvious on plain x-ray.
