Atypical Anti-MOG syndrome with aseptic meningoencephalitis and pseudotumor cerebri-like presentations

Objective: To describe 2 atypical cases with Anti-MOG antibody related demyelinating syndrome. Methodology: Case series. Results: We present two cases. Case 1 is an 18-year-old woman who presented with headache, blurred vision, and papilledema and was initially diagnosed with pseudotumor cerebri syndrome. CSF showed mildly elevated opening pressure and lymphocytic pleocytosis and a diagnosis of aseptic meningitis was considered. MRI brain and spinal cord revealed longitudinally extensive bilateral simultaneous optic neuritis and multiple spinal cord lesions. Case 2 is a 28-year old man who presented initially with unilateral optic neuritis followed by aseptic meningitis three weeks later and subsequently acute disseminated encephalomyelitis (ADEM). Serology was positive for Anti-MOG antibody on a cell-based assay in both these cases. Discussion: Although bilateral optic neuritis has been well described in MOG related disorders, aseptic meningitis and pseudotumor cerebri-like syndromes are notable alternate presentations. The presence of eosinophils in the CSF (in the first patient) is a unique finding in our case series. Conclusion: In a patient with an aseptic meningitis like presentation, the presence of optic neuritis, brain and/or spinal cord lesions should raise suspicion for an MOG-Ab related syndrome.