中頭蓋窩くも膜嚢胞と孔脳症—その臨床的，神経放射線学的検討

Intracranial Arachnoid Cyst and Porencephaly of the Middle Fossa: Its clinical and neuroradiological study

I．はじめに

　CT検査の普及にしたがって，頭蓋内に低吸収領野を示すextra-axial massを発見する機会は増えてきた．それらにはarachnoid cyst^9），intra-arachnoid cyst^15），孔脳症，その他が含まれているが，各種神経放射線学的検査を用いても診断は困難なことが多い．組織病理所見を得ても判断に苦しむこともある．

　著者らは，最近経験したintra-arachnoid cyst 1例，arachnoid cyst 1例，孔脳症2例の組織学的検索から，retrospectiveに神経放射線学的諸検査を再検討してみた．かなりの可能性をもって三者の鑑別が可能ではないかと考えるに至ったので，ここに報告する．

We reported four cases with well demarkated low densityarea in the middle cranial fossa, which was not enhanced withcontrast medium and had the same absorption coefficientas the CSF. The operations and histological examinationsrevealed that two cases were arachnoid cysts and the otherswere porencephalic cysts. The clinicoradiological differentialclues are listed below.

1) The porencephaly has intimate relation with focal neurological signs.

2) The thinning and bulging of the temporal bone are not a specific finding of an arachnoid cyst.