Case Report: Presenting as optic neuritis-a biopsy-proven IgG4 anti-NF155-positive combined central and peripheral demyelination syndrome.

Combined central and peripheral demyelination (CCPD) is a condition characterized by concurrent demyelination in both the central and peripheral nervous systems. To date, cases of CCPD presenting with isolated optic neuritis as the initial manifestation and positive for anti-neurofascin 155 (anti-NF155) antibodies are exceedingly rare. We herein report a case of a young male positive for anti-NF155 antibodies who developed severe optic neuritis and was subsequently diagnosed with CCPD via histopathological examination. This case highlights that CCPD may develop in patients presenting with optic neuritis as the initial manifestation, and underscores the critical importance of anti-NF155 antibody testing when concomitant peripheral neuropathy is identified.