Posterior Cerebral Artery Aneurysm Re-Rupture Following Revascularization for Moyamoya Disease

Objectives: Aneurysms associated with hemorrhagic moyamoya disease (MMD) are reported to stabilize or recede following revascularization. Case report/results: A 29 year-old male with no past medical history presented obtunded with diffuse intraventricular hemorrhage and vascular imaging demonstrating bilateral MMD without any associated aneurysms. He underwent a delayed right-sided STA-MCA bypass and pial synangiosis, and was subsequently discharged on hospital day 24 with a modified Rankin Scale score (mRS) of 2. He returned eleven days later from a rehabilitation facility with recurrent IVH. A saccular 5 mm right P4 segment posterior cerebral artery aneurysm was seen on a diagnostic angiogram and embolized with Onyx glue. Conclusions: Distal posterior circulation artery aneurysmal rupture is a rare cause of hemorrhagic MMD. This case demonstrates the capacity of these aneurysms to re-rupture following revascularization and underscores the importance of treating the aneurysms directly.