Intracranial dural arteriovenous fistula mimicking neuromyelitis optica spectrum disorder: A case report.

Neuromyelitis optica spectrum disorder (NMOSD) is an immune-mediated disorder. It often develops acute myelopathy due to longitudinally extensive transverse myelitis (LETM), although other disorders can cause an LETM-like lesion. Here, we report a 76-year-old patient presenting with acute-onset, progressive myelopathy, which proved to be caused by an intracranial dural arteriovenus fistula (dAVF). Magnetic resonance imaging (MRI) revealed a longitudinally extensive spinal cord lesion, which was further extended rostrally to the medulla. Although cord surface flow voids were absent on T2-weighted MRI, abnormally congested peri-spinal veins showed up with gadolinium contrast. Angiography confirmed dAVF in the posterior fossa, which drained into the peri-spinal veins. Intracranial dAVF should be considered as a differential diagnosis of NMOSD, because it is not immunologically but is surgically treatable.