Adult arteriosclerotic moyamoya.

Progressive idiopathic distal internal carotid artery occlusion in children and young adults associated with the development of bridging channels and tortuous, plethoric intracerebral arterial networks has been termed moyamoya or Nishimoto's disease. It is now generally recognized that this unusual angiographic patten results from collateral supply pathways and is not a primary angiomatous process. The authors describe 2 middleaged patients with intracranial arteriosclerotic occlusive lesions demonstrating secondary collateral patterns angiographically identical to moyamoya.