Ischemic stroke in young patients is an actual problem of modern angioneurology. You should know that in addition to the common causes of stroke (blood vessels, heart and circulatory system pathology, diabetes mellitus), one of the important ones is moyamoya disease. It has become more frequently registered among patients, including those of non-Asian origin in recent times. The disease often manifests itself as a stroke or transient ischemic attacks, and may initially be accompanied by various neurological manifestations for a long time. Late diagnosis of moyamoya disease due to the lack of knowledge of outpatient practitioners about this pathology may result in a stroke for the patient. It is a multifactorial disease with a genetic predisposition and is manifested by vascular remodeling in the system of internal and external carotid arteries (luminal occlusion) with the development of a collateral network resembling “cigarette smoke” during angiography. This defi nition is a literal translation of “moyamoya” from Japanese. The article gives a comprehensive, all-around view of the disease, the tactics of its detection and treatment, with an emphasis on modern methods of surgical revascularization. A clinical case from practice is of interest to internist clinicians as it is connected with atypical manifestation of the disease in an 18-year-old patient. The doctors focused on arterial hypertension as the main cause of the patient’s complaints, and moved away from the algorithm for detecting cerebral vascular pathology.