小脳実質内嚢胞—Isolated fourth ventricleの変異型

Cerebellar Cyst:A variant of isolated fourth ventricle

I．はじめに

　小脳実質内納胞の局在診断はCTにより容易であるが，嚢胞性小脳腫瘍を除くと文献上の報告は稀である．CT上，脳脊髄液循環系から隔離し，mass effectを呈した小脳実質内嚢胞の2症例を経験した．ともに水頭症を合併し，また，CT追跡上，病像の形成過程において脳室短絡手術後の変化を含む脳脊髄液循環動態の変化が関与しており，臨床上はisolated fourth ventricleの変異型とも呼ぶべき病像を呈した．追跡CTを主体として，文献上報告のみられない，この特異な病態形成の機序を考察するとともに，本病態に対する早期における外科的治療の必要性を指摘する．

Two cases of cerebellar cyst showing mass effect were presented as a treatable clinical entity not fully mentioned before. Analysis of the clinical data includ-ing follow-up computerized tomographic findings suggested its pathogenetical relationship to cerebellar porencephalic cyst following perinatal distress, and also, similarity to isolated fourth ventricle which would be encountered more frequently with the advent of computerized tomography in perinatal care.

The authors stressed the importance of early surgery during infancy as an effective therapeutic measure.