Moyamoya Disease is a Progressive Occlusive Arteriopathy of the Primitive Internal Carotid Artery.

SUMMARY The purpose of this literature review is to disclose the relationship between the temporal profile of steno-occlusive changes in the cerebral arteries in moyamoya disease and the embryological evolution of the cerebral arteries. Steno-occlusive changes and progression occur in the sequence of embryological evolution of the primitive internal carotid artery in the early embryological stage. In other words, steno-occlusive changes in the cerebral arteries occur primarily near the bifurcation of the cranial and caudal divisions of the primitive internal carotid artery, evolve from the cranial division to the caudal one, and progress from the bifurcation centrifugally. Steno-occlusive changes do not occur essentially in the distal cortical branches of the primitive internal carotid artery, in any arteries in the external carotid system, which are derived from ventral pharyngeal system and primitive stapedial system, or in any cerebral arteries in the vertebrobasilar system, which are derived from the longitudinal neural arteries.These facts suggest that moyamoya disease is strongly related to the vasculogenesis of the primitive internal carotid artery and genetic factors play a major role in the clinical manifestations of moyamoya disease.