Subarachnoid Hemorrhage Revealing Moyamoya Syndrome in a Patient With May-Hegglin Anomaly

INTRODUCTION: Moyamoya syndrome is a rare progressive cerebrovascular occlusive disease for which several associated conditions have been described. CASE REPORT: We report the case of a 76-year-old woman with a history of May-Hegglin anomaly who presented with an isolated unusual diffuse headache. Initial laboratory investigations showed only thrombocytopenia (platelet count 95000/μL). Unenhanced brain computed tomography scan revealed a small subarachnoid hemorrhage in the left frontal lobe. Computed tomography angiography showed occlusion of the terminal portion of the left internal carotid artery (ICA) and narrowing of the terminal portion of the right ICA with abnormal collateral vessels. Conventional angiography confirmed the tight stenosis of the extremity of the right ICA, and the occlusion of the left ICA, associated with an extensive collateral network consistent with moyamoya syndrome. No aneurysm was identified. CONCLUSIONS: The rarity of these 2 diseases makes a fortuitous association very unlikely. We thus concluded that this observation could be the first reported case of May-Hegglin anomaly as a cause of moyamoya syndrome.