外転神経麻痺で発症した三叉神経鞘腫の2例

Trigeminal Neurinoma Presenting Abducens Nerve Palsy as Initial Symptom:A report of two cases

I．緒言

　三叉神経鞘腫の発生頻度はSchisano and Olivecrona^13）によれば頭蓋内腫瘍5,727例中の0.2％と報告され，聴神経腫瘍との比率は約97対3である．初発症状は50％以上が顔面の知覚鈍麻，疼痛など第Ⅴ脳神経障害で発症するが^1,2,13,14），外転神経麻痺で発症するものは稀で，著者らの渉猟しえた限りでは，過去6例の報告をみるにすぎない^{5,6,8,12,14）}．著者らは外転神経麻痺で発症し，その後の経過中も他の症状がほとんどみられず，術前診断が困難であった三叉神経鞘腫を2例経験したので，外転神経麻痺の発生機序に対する考察を加えて報告する．

Two cases of trigeminal neurinoma presenting abducens nerve palsy as initial symptom are reported. Case 1. A 33-year-old female was admitted because of double vision of two months duration. Neurological examination revealed left abducens nerve palsy. CT scan disclosed a left paraseller tumor with a homoge-neous enhancement effect. The tumor was subtotally resected by left extradural subtemporal approach, and diagnosed as trigeminal neurinoma. Case 2. A 18-year-old female was admitted because of double vision of one month duration. Neurological examina-tion revealed left mydriasis and left abducens nerve palsy.