RESUMEN
INTRODUCTION: A wide range of medical conditions may mimic multiple sclerosis. Among them, cerebrovascular diseases, including moyamoya disease, need to be excluded since they share common clinical features and radiographic findings with multiple sclerosis. CASE REPORT: A 44-year-old woman experienced transient numbness of her right sided face and arm and was referred to our unit due to small brain lesions in magnetic resonance imaging, with a possible diagnosis of multiple sclerosis. Neurological examination was unremarkable except for plantar reflexes and jerky deep tendon reflexes. Brain magnetic resonance angiography revealed findings typically seen in moyamoya disease, confirmed with digital subtraction angiography. Antiplatelet therapy started, but few days later, she developed suddenly global aphasia and right hemiparesis (National Institutes of Health Stroke Scale/NIHSS 6). Brain magnetic resonance imaging revealed acute infarct in the distribution of the left middle cerebral artery. At her discharge, she was significantly improved (NIHSS 3). CONCLUSION: Diagnosis of multiple sclerosis is often challenging. In particular, in young patients with transient neurological symptoms and atypical white matter lesions in magnetic resonance imaging, cerebrovascular disorders such as moyamoya disease should be considered in the differential diagnosis. Detailed clinical and neuroimaging evaluation are mandatory for the correct diagnosis.