Viral encephalitis: A mere evil doppelganger or a mini-me of glioblastoma

Background: Viral encephalitis and glioblastomas can have a very variable clinical and radiological presentation. Although they are both relatively rare, they are known to mimic each other.Methods: In this study, we retrospectively analysed the radiology databank from 2010 to 2020 to find cases which were initially suspected to be viral encephalitis based on their imaging and clinical parameters but were later diagnosed with glioblastomas on final histopathology. The initial imaging at the time of presentation was reviewed by three radiologists having experience of 18, 15 and 6 years in neuroimaging, and the follow-up imaging data were also reviewed by the same set of radiologists, and the results were recorded. Age- and sex-matched controls of confirmed viral encephalitis were also extracted from the same database.Results: We found three such cases which were initially diagnosed with viral encephalitis but rapidly progressed to glioblastoma in the region of suspected encephalitis. The average age of these patients was 60 years and all of them were males. All these cases had a very short history and the cerebrospinal fluid examination of all of these patients had tested negative for herpes simplex virus at the time of initial presentation.Conclusions: The development of glioma exactly at the site of initial encephalitic abnormality suggests an association between these two entities, which needs further prospective studies for validation and correlation with post-mortem histopathology. Furthermore, the fact that these glioma patients showed initial clinical improvement with antiviral drugs suggests a strong point towards such an association.