Multiple dural arteriovenous malformations. Report of two cases.

Two cases of multiple dural arteriovenous malformations (AVM's) in different locations are reported. One patient was diagnosed as having a dural AVM involving the right cavernous sinus that disappeared spontaneously 4 months after onset of symptoms. After an interval of 4 months, another dural AVM appeared involving the right lateral sinuses (transverse and sigmoid sinuses) with occlusion of the right sigmoid sinus. In the other patient, multiple dural AVM's were demonstrated on angiography, one involving the cavernous sinus and the other the left lateral sinus. The frequency of multiple occurrence and possible mechanisms of sinus occlusion are discussed.