Ewing sarcoma of the skull with an unusual pattern of reactive sclerosis: MR characteristics.

A case of primary Ewing sarcoma involving the occipital bone with an unusual radiographic feature--markedly thickened bone--is described. Magnetic resonance imaging was more helpful than CT in determining the lesion extent due to lack of bone artifact and since it showed the precise relationship of the neoplasm to the tentorium on direct coronal imaging.