Extrasinusal dural arteriovenous malformations. Report of three cases.

Of 60 cases of dural arteriovenous malformations (DAVM) explored and treated in the Vascular Neuroradiology Unit of the Hospital of Bicêtre between 1980 and 1986, 3 presented in an extrasinusal location: intraorbital, middle cerebral fossa and the region of the superior orbital fissure. We have not found any prior description of DAVMs in these regions in the literature. The classic concept that DAVMs arise in direct relationship with the dural sinuses is limited. We believe that these lesions may also develop in relationship with the venous drainage system of the sinuses and the venous drainage of the peripheral nervous system. We note that the superior ophthalmic vein which drains DAVMs of the orbit and the olfactory vein which drains DAVMs of the anterior cranial fossa and other veins that accompany the cranial nerves through the skull base have the characteristics of emissary veins. It may be that DAVMs can develop wherever veins follow a transosseous trajectory.