Extraskeletal Ewing's sarcoma.

Ewing sarcoma (E.S.) is a rare malignant tumour of the bone, dubious in origin and uncertain in the direction of its differentiation [2,3,7,10]. Recent reports have presented description of primary neoplasms of soft tissues which revealed no differences from E.S. in light and electron-microscopy but had no connection with the skeleton [1,4,5,6,8,9]. These lesions, found in subcutaneous tissue of the trunk and limbs, in the retroperitoneum and in paravertebral regions were called extraskeletal Ewing sarcoma (E.E.S.) or soft tissue Ewing sarcoma. As tumours of this type are infrequent and may cause diagnostic difficulties, we shall present a recently diagnosed case of extraskeletal Ewing sarcoma.