同胞に見られた一側性内耳空洞様奇形

Unilateral Cystic Inner Ear Anomaly in Siblings

　I．はじめに

　他に奇形を持たない一側性高度難聴を伴う内耳奇形は従来稀なものとして時に報告されるが，同胞（兄・妹）において内耳道狭窄を伴う，ほぼ類似のX線所見を示す内耳の空洞様奇形の珍しい症例を報告し，併せて諸種の検査所見とX線学的所見との関連性，空洞様奇形のX線学的分類，発現等に関して若干の文献的考察を試みた。

　Unilateral cystic inner ear anomaly was found in siblings, a 9-year-old boy and a 6-year-old girl.

　X-ray examinations of the temporal bone, audiological examinations and vestibular function tests were performed.

　Tomographic x-ray findings showed an enlarged solitary sac type deformity of the vestibule with a narrowing of the internal auditory canal, severe hypoplasia of the anterior semicircular canal and no visualized cochlea in the right ear, and these findings were identical in the right ear of both children.

　Puretone audiometry revealed severe mixed type of hearing loss in the right ear in both children. The vestibular function tests showed no response especially in caloric test.