A progressive occlusion of the internal carotid arteries in a case of adult-onset moyamoya disease.

Progressive occlusions of the intracranial portions of ICAs are already established phenomena in childhood-onset moyamoya disease, but they have not yet been demonstrated in adult-onset patients. A patient with moyamoya disease manifested at 25 years of age was examined with cerebral angiography at 27 and 45 years of age. The angiograms taken at 27 revealed that the right ICA was completely occluded at the clinoidal portion, while the left one was patent and the occlusive/stenotic change was limited to the terminal portion. Angiograms taken 17 years later revealed that the right ICA was occluded at the origin, while the left one concentrically narrowed at the origin, then tapered off and was occluded at the clinoidal portion. The present case suggests that the ICA occlusion of moyamoya disease is not limited to the intracranial segment but progresses to the cervical segments, even in adult-onset patients. Based on these findings, two different groups of adult-onset moyamoya disease may exist; one in which the occlusive disorder has been completed by the time clinical manifestations appear and thereafter decreases, while the other group consists of occlusive disorders that steadily progress to the original portion of ICA.