(Sub)periosteal Ewing's sarcoma of bone.

Ewing's sarcoma is a small malignant round-cell tumour that arises from mesenchymal cells, predominantly in the medullary cavity of bone. In exceptional cases it originates in the soft tissues and subsequently invades the underlying bone. A (sub) periosteal origin of Ewing's sarcoma is a very rare condition: only a few cases have been published so far. Three cases of (sub)periosteal Ewing's sarcoma, having received neoadjuvant chemotherapy and radiation therapy as well as wide excision, are reported.