術前診断にDiffusion Imageが有用であった小脳橋角部Endodermal Cystの1症例

Endodermal Cyst of the Cerebellopontine Angle Cistern : case report

I．はじめに

　Endodermal cystは嚢胞壁が気管上皮や腸上皮に類似する上皮からなる嚢胞であり，enteroge-nous cyst，neuroenteric cyst，bronchogenic cyst等も含む総称名で多くは脊髄前面の硬膜下腔に発生する^17）．小脳橋角部に発生することは稀であり，われわれが渉猟し得た範囲では現在までに10例が報告されているにすぎない^{5,8,9,11,12,14-16,18,21）}．今回小脳橋角部に局在し，組織学的にendodermal cystと診断された1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．

We report a case of a 55-year-old man with endodermal cyst located in the cerebellopontine angle cis-tern. The patient presented with dizziness. Magnetic resonance imaging (MRI) revealed multilocular cysticlesion at the right cerebellopontine angle. Tl-weighted image showed a mass with a low signal intensity,but higher intensity than CSF. Gd-DTPA T1-weighted image showed no enhancement in the mass.Diffusion-weighted image showed a mass with no signal lesion. After successful surgical removal, it wasfound to be an endodermal cyst. These cysts have usually been found in the spinal canal, and their in-tracranial occurrence is exceptional. The unusual location of the cyst and its histological features andradiological findings are discussed.