頭蓋頸髄移行部にみられた硬膜内クモ膜嚢胞の1例

An Intradural Arachnoid Cyst of the Craniovertebral Junction; A case report

I．はじめに

　脊髄硬膜内クモ膜嚢胞は比較的まれな疾患とされているが，現在までに約130例の報告^1-14）がある．しかし，頭蓋脊髄移行部に発生したものはきわめてまれである．また，その成因については先天発生説^7,14）外傷説3,6,7，^13,14），炎症説など諸説がある．今回われわれは，外傷16年後に，後頭蓋窩から上位頸髄に発生した硬膜内クモ膜嚢胞の1例を経験したので報告する．

Abstract

　An intradural arachnoid cyst of the craniovertebral junction possibly of traumatic origin is reported. A 59-year-old man was admitted to our hospital with a 10-month history of progressive gait disturbance. He had a history of head injury with a fracture of the occipital bone. Myelography revealed pooling of the contrast medium in the posterior fossa and on the dorsal sides of C₁ and C₂. Metrizamide-enhanced computed tomography also showed pooling at the same level.Magnetic resonance imaging indicated a large cystic lesion at the craniovertebral junction. Craniectomy of the posterior fossa and laminectomy of C₁, C₂ and C₃ were performed, and an intradural cyst with thickened dura and arachnoid was found. The cyst wall was opened to communicate with the subarachnoid space. Histological findings of the specimen showed that the arachnoid was thickened.

　There are over 130 reports of intradural arachnoid cyst of the spine, but those of traumatic origin are rare, and cysts located in the intracranial to spinal region are extremely rare.