孔脳症を伴い，鑑別診断に難渋した類皮腫の1例

Atypical Presentation of a Dermoid Cyst with Porencephaly

Ⅰ．はじめに

　頭蓋内類皮腫は全脳腫瘍の0.1〜0.3％と非常に稀であり，嚢胞壁と嚢胞内容からなる先天性腫瘍である．通常，本腫瘍はCT上著明な低吸収域を示し，造影剤による造影効果はみられないとされており，類皮腫に合併する奇形としても先天性皮膚洞^3），二分脊椎^6），Klippel-Feil症候群^10）などが多いとされている．本症例のように．単純CTで高吸収域を呈し，孔脳症を合併した報告例は比較的稀と考えられ，若干の文献的考察を加え報告する．

We report a case of a dermoid cyst in the parasellar area associated with porencephaly. A 22-year-old man pre-sented with headache and visual disturbance. Non-enhanced brain CT showed a high density mass in the parasellar area and a low density area in the left temporal lobe. On gadolinium-enhanced T1-weighted images, a partial rim en-hancement was present in the parasellar region. A presumptive diagnosis of Rathke cleft cyst, craniopharyngioma, non-function pituitary adenoma, or germ cell tumor was considered.

A left frontotemporal craniotomy was performed and the tumor was removed almost totally.