[Ewing's sarcoma at the occipital bone presenting as acute epidural hematoma: a case report].

Primary cranial Ewing's sarcoma is rare. We describe an exceptionally rare case of primary Ewing's sarcoma of the occipital bone, presenting as spontaneous acute epidural hematoma. A 19-year-old female was admitted to our hospital complaining of sudden onset of severe headache. There were no neurological deficit and no abnormal laboratory findings. Computerized tomographic (CT) scan revealed a lentiform shaped high density lesion at the left occipital epidural space. Magnetic resonance imaging (MRI) showed the lesion as iso to low intensity on T1-weighted image (T1WI) and mixed signal intensity on T2-weighted image (T2WI). There were no pathological findings at the adjacent brain. Cerebral angiography demonstrated mass effect. Right occipital craniotomy was performed. We found the tumor arising from the occipital bone and located at the epidural space. The tumor was resected totally. Histological examination revealed the tumor as Ewing's sarcoma with intratumoral hemorrhage. The postoperative course was uneventful. Radiation therapy (50Gy) was given. Follow-up examination six years after the treatment found no evidence of tumor recurrence or distant metastasis. It should be born in mind that primary Ewing's sarcoma of the skull can cause spontaneous acute epidural.