急性硬膜外血腫所見にて初発した後頭骨原発Ewing肉腫の1例

Ewing's Sarcoma at the occipital bone presenting as acute epidural hematoma:a case report

I．はじめに

　Ewing肉腫は悪性骨腫瘍の5％から7％を占め^22），大腿骨や上腕骨等の長管骨に多く発生する腫瘍であり，頭蓋骨に原発することは極めて稀である^5,29．今回われわれは，突然の激しい頭痛で発症し，急性硬膜外血腫所見を呈した後頭骨原発のEwing肉腫に対して，摘出術および放射線療法により，術後6年経過した現在再発なく経過した症例を経験したので報告する．

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 labora-tory findings. Computerized tomographic (CT) scan re-vealed 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 pathologi-cal 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 re-vealed the tumor as Ewing's sarcoma with intratumoral hemorrhage. The postoperative course was uneventful. Radiation therapy (50Gy) was given. Follow-up ex-amination six years after the treatment found no evi-dence of tumor recurrence or distant metastasis. It should be born in mind that primary Ewing's sar-coma of the skull can cause spontaneous acute epidural hematoma.