経過中に腫瘍内出血を来たした嚢胞性髄膜腫の1例

Intratumoral Hemorrhage Associated with Cystic Meningioma under Observation : a case report

I．はじめに

　嚢胞性髄膜腫は全髄膜腫の約2％とされ，症例報告も散見されるが，その多くは主に特殊な画像所見と嚢胞の発生機序について検討がなされている．しかし発生機序に関しては多くが病理所見からの推測であり，嚢胞の形成過程を経過を追って確認できた報告例は少ない．今回われわれは嚢胞性髄膜腫症例の経過中に，腫瘍内出血を来たし，嚢胞の増大過程を偶然画像所見として捕えることができた1症例を経験した，髄膜腫における腫瘍内出血も稀な病態であり，嚢胞性髄膜腫の嚢胞形成機序を中心に報告する．

Cystic meningiomas are not commonly encountered and are said to account for only 1 to 2% of all typesof meningioma. There have been several reports on them and most of them were discussed under theaspect of the mechanism of cystic formation. Though few reports present the process of cystic formation,here we were able to present the process of cystic formation with intratumoral hemorrhage. The case wasa 56-year-old man who presented with urinary incontinence. MRI revealed a large cystic tumor in the rightfrontal lobe and he was admitted to another hospital. After 20 days, MRI incidentally revealed hematomanear the intratumoral cyst. Two weeks later, MRI revealed that the hematoma flowed out to the cyst andthe cavity of the hematoma communicated with the cyst. Angiography showed that the tumor was fed bythe left anterior ethmoid artery, After surgical removal of the tumor, histopathological diagnosis was thatthe tumor was a transitional nleningioma and there were no findings of malignancy. Commonly, intratumo-ral hemorrhage is unusual for a meningioma but we suspect that there are not a few cases in which smallhemorrhage occcurred without symptoms and the hematoma cavity joined the intratumoral cyst while thecyst grew gradually.