Subarachnoid Hemorrhage from Vertebral Arteriovenous Fistula without Perimedullary Drainage: Rare Stroke Hemorrhagic Event in a Patient of Neurofibromatosis Type 1

Vertebral arteriovenous fistula (VAVF), which can cause subarachnoid hemorrhage (SAH) when having a perimedurally drainage, has been reported as a rare vascular abnormality in patients with neurofibromatosis type 1 (NF-1). In addition, extracranial vertebral aneurysm (EVAn) coexisting with VAVF and NF-1 is considered rare, and further complication with SAH is extremely rare in patients. There is only one reported case of NF-1 complicated with SAH from VAVF with an EVAn. Here, we present a case of a middle-aged patient with NF-1. The VAVF accompanied by an EVAn was detected with an episode of SAH. The VAVF with an EVAn in our case was accompanied with an epidural varix, lacking of perimedullary drainage, which could be a cause for SAH. We speculate the mechanism of SAH from the VAVF with an EVAn lacking of perimedurally drainage, focusing on hemodynamic stress of the VAVF and the tissue fragility related to NF-1.