Holocord myelopathy misdiagnosed as neuromyelitis optica spectrum disorder (NMOSD): A unique case of dural arteriovenous fistula at the craniocervical junction along first spinal nerve.

Background: Dural arteriovenous fistulas (DAVFs) at the craniocervical junction (CCJ) involving the first spinal nerve represent a particularly rare and challenging subtype of DAVFs, with holocord myelopathy secondary to cerebrospinal DAVFs being an exceedingly rare presentation. Case Description: We report the case of a 70-year-old woman who presented with progressive paraparesis over 2 weeks. Initial magnetic resonance imaging (MRI) of the spine showed extensive holocord myelopathy, leading to a misdiagnosis of inflammatory myelopathy and subsequent inappropriate steroid treatment at a local hospital, which exacerbated her neurological symptoms. On transfer to our institution and further evaluation with MRI and magnetic resonance angiography, a lower thoracic DAVF was initially suspected. However, comprehensive spinal angiography failed to localize the fistula, prompting cranial angiography, which ultimately identified a DAVF at the CCJ along the C1 nerve root, supplied by a small radiculomeningeal branch of the left vertebral artery. Successful management involved coagulation of the proximal draining vein, with follow-up imaging confirming complete fistula obliteration and resolution of the holocord edema. Conclusion: This case highlights the diagnostic and therapeutic challenges associated with DAVFs at the CCJ, particularly when presenting with holocord myelopathy. It underscores the importance of a high index of suspicion and the need for timely, accurate diagnosis and intervention to prevent permanent spinal cord damage in such rare and complex cases.