後大脳動脈末梢部（P4 segment）動脈瘤の1例

Peripheral Branch (P4 segment) Aneurysm of the Posterior Cerebral Artery: A case report

I．はじめに

　後大脳動脈瘤は椎骨脳底動脈領域の動脈瘤の7-33％（約15％）^16）であり，特にP₁，P₂部に多く，P₃以下のdistal PCA動脈瘤は稀なものと思われる．今回，われわれは，硬膜下血腫，脳内血腫，脳室内出血を伴った後大脳動脈末梢部（P₄）動脈瘤を経験したので，文献的考察を加え報告する．

　Four to fifteen percent of all intracranial aneurysms reported are peripheral aneurysms of the posterior fossa. Peripheral branch aneurysm of the posterior cerebral artery has only rarely been described.

　A 69-year-old woman had sudden onset of severe headache and vomiting and was transfered to our hospital. On admission the patient showed mild mental impairment. She had signs of meningeal irritation and right homonymous hemianopsia.

　CT scan showed intracerebral hematoma in the left occipital lobe, large hematoma in the left lateral ventricle and subdural hematoma in the interhemispheric region.