Delayed Intracerebral Hemorrhage 15 Years After Indirect Revascularization in Moyamoya Disease: A Case Report and Review of the Literature.

Background and Clinical Significance: Moyamoya disease (MMD) is a progressive intracranial vasculopathy characterized by stenosis or occlusion of the terminal internal carotid arteries and the development of fragile collateral networks. It predisposes patients to ischemic and hemorrhagic strokes. Although both direct and indirect revascularization procedures are recommended to restore cerebral blood flow, recurrent cerebrovascular events may still occur, and delayed hemorrhage following revascularization is particularly uncommon. Case Description: We report the case of a 42-year-old woman who presented with seizure, syncope, and aphasia. Cranial computed tomography (CT) revealed a large left temporal-insular intraparenchymal hematoma with a midline shift. Computed tomography angiography (CTA) demonstrated bilateral internal carotid artery narrowing and collateral vessel proliferation, without aneurysm. Her history indicated a hemorrhagic stroke 15 years earlier, at which time MMD was diagnosed by magnetic resonance angiography (MRA) and managed with multiple burr hole surgeries. She remained free of cerebrovascular events until the current presentation. The patient underwent emergent hematoma evacuation, followed by intensive care management. Postoperatively, she demonstrated neurological improvement, though with residual motor aphasia and right-sided weakness, and was discharged for rehabilitation. Conclusions: This case underscores the rare occurrence of delayed intracerebral hemorrhage 15 years after indirect revascularization in MMD. Although revascularization surgery remains the standard therapeutic approach, this report highlights the importance of sustained long-term surveillance, strict risk factor management, and careful postoperative follow-up. The key point is that late hemorrhagic complications, though uncommon, must be considered in the long-term care of MMD patients following revascularization.