A 21-year-old male presented with headache, unilateral optic neuritis, and left sided weakness in 2013. MRI Brain revealed a right temporal lesion extending to the internal capsule, thalamus, and basal ganglia. CSF studies showed a lymphocytic predominance, elevated IgG index, twelve oligoclonal bands, and positive EBV PCR in the CSF. He otherwise had a negative infectious workup. He was diagnosed with MS and treated with IV methylprednisolone. He presented one month later with worsening left sided weakness and left sided ataxia. Repeat MRI brain showed involvement of the right corona radiata, midbrain, insula, and frontal lobe. A biopsy was ultimately obtained due to rapid progression; this was consistent with tumefactive demyelination.  

After repeating treatment with steroids, natalizumab was initiated but discontinued in 2017 due to positive JC virus. He unfortunately had breakthrough radiographic activity that year and thus transitioned to ocrelizumab. As he exhibited atypical clinical and radiographic features of MS, in 2020, serum Mog-IgG was tested and was positive with a 1:100 titer. IVIG was initiated with the patient achieving stable disease activity, although later he had to stop IVIG due to dermatitis. His overall course has been complicated by right temporal lobe epilepsy, with semiology described as a "rush sensation," loss of awareness, and ictal emesis.