These usually occur in the intracranial part of the internal carotid artery and the basilar artery and are usually seen in elderly patients with advanced cerebral atherosclerosis. They may result in transient ischaemic attacks, infarction due to thrombosis, or haemorrhage. There are a variety of different types of vascular malformation, classified on the basis of the type of blood vessels present and on the configuration of the vascular channels. These include arteriovenous malformations, cavernous angioma, venous angioma, and mixed types. They are regarded as congenital in origin.
Arteriovenous malformation is the most significant of the group and is the most likely to bleed.
They may present at any age but most commonly present in the second to the fourth decade. They may be asymptomatic. Arteriovenous malformation within the cerebral cortical grey and white matter. Cavernous haemangioma often occurs as a familial disorder and may be multiple. They may occur anywhere in the brain or within the leptomeninges that are most common in the subcortical white matter, pons and internal capsule.