Hypoglossal Canal Dural Arteriovenous Fistula: A Rare Cause of Ocular Proptosis.

It is exceedingly rare for dural arteriovenous fistulae (DAVFs) outside of the cavernous sinus to present with ophthalmological symptoms and signs. Hypoglossal canal DAVFs (HC-DAVFs) have only previously been reported as individual cases or small case series. Further, only an estimated 31% of HC-DAVFs present with ophthalmological findings. We report a noteworthy case of an HC-DAVF in a 74-year-old male who presented with proptosis, chemosis, and reduced visual acuity. He was treated endovascularly with liquid embolic filling. This report aims to highlight HC-DAVF as an important differential diagnosis for patients presenting with symptoms suggestive of arterialisation of the ophthalmic veins.