A Case of a Ruptured Lenticulostriate Artery Aneurysm Associated with Moyamoya Disease

Abstract

We report a case of a ruptured lenticulostriate artery (LSA) aneurysm, associated with moyamoya disease, which was removed surgically. A 25-year-old female presented with right intraventricular hemorrhage. Cerebral angiography revealed moyamoya disease and a right LSA aneurysm. Antihypertensive therapy was initially administered, followed by a scheduled bypass. On day 5, rebleeding was noted and cerebral angiography on day 9 showed aneurysmal enlargement. We performed bypass surgery (superficial temporal artery-middle cerebral artery and encephalo-myo-synangiosis) to prevent further rebleeding. A high intensity lesion on T1 weighted magnetic resonance imaging (MRI) was observed around the aneurysm on the 5^th postoperative day. Repeat cerebral angiography showed residual aneurysm. Therefore, rerupture of the aneurysm was anticipated. Because the aneurysm was fusiform in shape, trapping and excision was performed on day 16. Postoperatively, the patient had transient left hemiparesis. Three months later, her modified Rankin Scale improved from 4 to 1. Histopathological diagnosis showed a true aneurysm based on the thin aneurysmal body wall and smooth muscle. For cases wherein a residual aneurysm is present and reruptures after bypass, surgical treatment for the aneurysm is required. Surgical intervention, in the form of excision or clipping, might be effective for the treatment of ruptured aneurysms associated with moyamoya disease to prevent rerupture during the acute phase.