Encephalitis, vasculitis, and acute disseminated encephalomyelitis are all known CNS manifestations of varicella zoster infection. In the absence of any diffusion restriction, enhancement, or mass effect, and with the involvement of the midbrain, basal ganglia, and left cerebellar hemisphere, a probability of acute disseminated encephalomyelitis (ADEM) was raised.

However, further pathological investigations turned out to be positive for myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). This case again highlights that imaging findings between ADEM and MOGAD overlap and are often indistinguishable.

The patient was started on antiviral drugs and steroids and improved significantly.