A rare case of concurrent longitudinally extensive myelitis and retinal vein occlusion.

Neurosyphilis can affect multiple organ systems, but simultaneous involvement of the spinal cord and retinal vasculature is exceedingly rare. We report a 36-year-old man presenting first with unilateral branch retinal vein occlusion (BRVO) and, two weeks later, progressive paraparesis due to longitudinally extensive transverse myelitis. Serologic tests were positive for syphilis, and cerebrospinal fluid (CSF) VDRL confirmed neurosyphilis. Spinal MRI showed a longitudinal T2-hyperintense lesion from C4 to the conus. Intravenous penicillin led to clinical and radiographic improvement. This case highlights the clinical relevance of syphilis as a "great imitator" - manifesting concurrently as ocular vasculitis and spinal cord demyelination. This case highlights an exceedingly rare, concurrent presentation of BRVO and longitudinally extensive myelitis as the primary manifestation of neurosyphilis. We propose syphilitic vasculitis as the unified underlying mechanism. This report underscores the critical need for clinicians, particularly ophthalmologists and neurologists, to maintain a high index of suspicion for syphilis in patients with unexplained neurologic or vascular ophthalmologic findings.