A rare pure intraventricular hemorrhage caused by ruptured internal carotid artery-anterior choroidal artery aneurysm: a case report and literature review.

Although intraventricular hemorrhage (IVH) frequently develops secondary to intraparenchymal or subarachnoid hemorrhage, pure IVH-non-traumatic spontaneous intracranial hemorrhage confined to the cerebral ventricular system-is rare. Moreover, pure IVH caused by ruptured proximal aneurysm is an extremely rare but life-threatening condition. Herein, we present a case of pure IVH due to a ruptured internal carotid artery -anterior choroidal artery (ICA-AChA) aneurysm and review related literature. A 77-year-old man presenting with altered mental status was hospitalized due to a massive pure IVH with ventriculomegaly. The patient was conservatively managed because his consciousness level improved. On the following day, computed tomography angiography revealed a right ICA-AChA aneurysm embedded in the temporal lobe adjacent to the anterior part of the inferior horn of the lateral ventricle, which was consistent with the hemorrhagic origin. Coil embolization of the aneurysm was successfully performed, and the postprocedural course was uneventful. To date, only a few cases have described pure IVH caused by a ruptured proximal aneurysm. If the ruptured proximal aneurysm remains unnoticed, catastrophic rehemorrhage may occur. Aneurysm obliteration should precede the treatment of acute hydrocephalus. Neurosurgeons/neurointerventionalists must be aware about pure IVH caused by a ruptured proximal aneurysm even if it rarely occurs.