下垂体腺腫の放射線照射後に発生したMalignant Astrocytomaの1例

Malignant Astrocytoma following Radiotherapy for Pituitary Adenoma: Case report

I．はじめに

　脳腫瘍の放射線治療において，照射後に組織学的に異なる腫瘍が発生する放射線誘発腫瘍が問題とされているが，中枢神経系誘発腫瘍の多くは髄膜腫と肉腫で^{12,20,27，33,34）}，グリオーマは少数であり，渉猟し得た限りでは38例の報告^{1-3,5-7,10,11,13-19,21-27,29-32,34）}がある。本邦では1977年にKomakiら^14）が頭蓋咽頭腫の放射線照射後6年目に右側頭葉に発生したglioblastoma例を記載して以来，2例^14,21）の報告をみるに過ぎない．

　今回，下垂体腺腫に対して放射線療法を行い，4年6カ月を経てmalignant astrocytomaが右側頭葉に発生した放射線誘発腫瘍の1例を経験したので，若干の文献的考察を加えて報告する．

A case of malignant astrocytoma following radiother-apy for pituitary adenoma is presented in detail with a review of the literature.

A 38 year old housewife had developed a growth-hormone secreting pituitary adenoma, and received a total of 50 Gy at the pituitary region. Four years and six months later, she began suffering headache and vomiting. Computed tomography showed an extensive low density with ring enhancement in the right tempor-al region, corresponding to the previously irradiated field. A right frontotemporoparietal craniotomy was carried out, and a soft and reddish tumor was partially removed.