頭蓋咽頭腫照射療法2年後に発生した髄膜腫の1小児例

A Juvenile Case of Radiation-induced Meningioma Two Years after Radiation for Craniopharyngioma

I．はじめに

　1969年Munkら^3）の頭部白癬に対する低線量照射療法後に生じた5例の頭蓋内髄膜腫の報告以来radiation—induced meningiomaの報告は300例近く認められている^8）．今回頭蓋咽頭腫照射療法2年後に発生した髄膜腫の1小児例を組織学的，免疫組織化学的，電顕的及びその増殖能に関し検索したので報告する．

The patient was a 7-year-old boy who recieved radia-tion therapy of 50 Gy after total gross removal of a cra-niopharyngioma. After two years a follow up CT scan showed a new enhanced lesion in the right temporal tipwithin the previous irradiation field. Total removal of the tumor was performed and its histological examina-tion showed it to be an atypical meningioma. This aty-pical meningioma satisfied Cahan's criteria. So we dia-gnosed this atypical meningioma as radiation-induced meningioma. Immunohistochemically this meningioma stained for Vimentin. An electronmicroscopical ex-amination showed neither desmosome nor interdigita-tion. The score of Ki-67 and. BrdU-L. I. was very small. Compared with previously reported juvenile radiation-induced meningioma, the latency was very short. The patient received growth hormone (GH) replacement therapy. We suspected relation between GH replace-ment therapy and short latency. He was discharged without any new neurological deficits and we haven't detected tumor recurrence for two years.