arteriovenous angioma of the brain, a congenital tumor consisting of a tangle of coiled, usually dilated arteries and veins, islets of sclerosed brain tissue, and, occasionally, cartilaginous cells. The lesion, which may be distinguished by an intracranial bruit, generally arises in the vascular system of the pia mater and may grow to project deeply into the brain, causing seizures and progressive hemiparesis.
