内頸静脈を通じ頭蓋外へと進展した髄膜腫の1手術例

A Case of Meningioma with Extracranial Extension Through the Internal Jugular Vein

Ⅰ．はじめに

　われわれは後頭蓋窩起源でありながら内頸静脈内を通じ頸部へ達する頭蓋外進展を示し，さらに頭蓋内外で異なる組織像を呈した髄膜腫の1手術例を経験した．このような症例は極めて稀であり，本症例の手術所見および病理所見をもとに頭蓋外進展機序を中心に報告する．

We report a case of posterior fossa meningioma extending into the cervical jugular vein,which was successfully resected. A 57-year old male with ataxia and mild hypogeusia was admitted to our hospital. MRI demonstrated a well-circumscribed large posterior fossa mass with extracranial extension through the internal jugular vein. Twostaged surgical treatment was then performed. The mass in the posterior fossa was removed at the first operation. The tumor was invading into the sigmoid sinus which was filled with tumor. The second operation for extracranial mass was performed 1 month later. Transcervically, the internal jugular vein obstructed by tumor was successfully removed. The post-operative course was uneventful and histopathological examination revealed the fibrous meningioma in the posterior fossa, but the intravenous portion of the tumor showed more atypical findings. Such a case is quite uncommon and the mechanism of tumor extension with different histological features is discussed.