Uncommon symptomatic cerebral vascular malformations.

We describe three cases of unusual vascular malformations in which the most relevant angiographic findings were the presence of a pathologic arteriovenous shunt through multiple small direct arteriovenous fistulas and the lack of a clearly identifiable nidus. All malformations were symptomatic. Such lesions are relatively rare, but they should be taken into consideration in the differential diagnosis of cerebrovascular malformations.