Bowel Ischemia as a Rare Manifestation of Extracranial Moyamoya Disease: A Case Report.

BACKGROUND Moyamoya disease (MMD) is a rare, progressive cerebrovascular disorder characterized by bilateral stenosis or occlusion of the internal carotid arteries and the development of fragile collateral vessels within the circle of Willis. The disease primarily affects the intracranial vasculature, with extracranial manifestations being exceedingly uncommon. Gastrointestinal (GI) involvement, in particular, is rarely described in the literature. CASE REPORT We present the case of a 20-year-old White man with a known diagnosis of MMD who developed severe gastrointestinal complications. He presented with persistent coffee-ground emesis, fatigue, and dizziness. Initial investigations revealed microcytic anemia, and upper-GI endoscopy showed advanced esophagitis and duodenal ulceration. Further imaging demonstrated mesenteric artery stenosis, suggestive of vascular involvement outside the cerebral circulation. Despite medical management, the patient required multiple blood transfusions due to ongoing bleeding and symptomatic anemia. This case is notable for its atypical presentation of MMD with systemic vascular involvement extending beyond the central nervous system. The presence of mesenteric artery stenosis and upper-GI tract ulceration raises the concern for extracranial arteriopathy potentially linked to the pathophysiologic processes of MMD. CONCLUSIONS Clinicians should maintain a high index of suspicion for extracranial involvement in patients with MMD who present with unexplained systemic symptoms, particularly gastrointestinal bleeding. Early recognition and multidisciplinary intervention are essential to mitigate complications and improve outcome.