回転性めまいが初発症状であった聴神経腫瘍の3症例

Three Cases of Acoustic Neurinoma Presenting with Episodic Vertigo

　はじめに

　聴神経腫瘍は頭蓋内腫瘍のおよそ8〜10％，小脳橋角部腫瘍の約80％を占めている^1）。その臨床像は蝸牛症状や前庭機能障害，小脳症状，顔面神経麻痺，三叉神経障害など多岐にわたるが，回転性めまいは19％と比較的少なく，初発症状となる症例は7％に過ぎない^2）。

　われわれは，回転性めまい発作を初発症状として当科を受診し，諸検査の結果，聴神経腫瘍と診断された3症例を経験したので，若干の文献的考察を加えて報告する。

In these three cases MRI revealed small sized tumors (≦10 mm) restricted in the internal auditory canals.Since the internal auditory canal is narrow and sur-rounded by bone tissue, it is considered that vestibular nerves and arteries which feeds the inner ear, can be easily affected by the rapid growing tumor, and con-seqently, vertigo may occur. However, in terms of direc-tion of nystagmus during vertigo attack, it is suggested that there is not only one etiology how vertigo occur in patient with acoustic neurinoma but some complex fac-tors must also be concerned.