“Moyamoya disease is a rare, progressive cerebrovascular disorder caused by blocked arteries at the base of the brain in an area called the basal ganglia. The name “moyamoya” means ‘puff of smoke’ in Japanese and describes the look of the tangle of tiny vessels formed to compensate for the blockage.” See more here.
Sample case: Healthy female in early 30s with stroke-like symptoms. Work up reveals Moyamoya.