Catastrophic Presentation of COVID-19 with Solitary Large Denovo Tumefactive Demyelination.

Background The ongoing Coronavirus disease-19 (COVID-19) pandemic has revealed a plethora of extrapulmonary manifestations including neurological presentations. To date, nervous system demyelination has been relatively infrequently reported in this setting. Also, while most data point toward immune activation as a causative process, few studies propound a direct effect. Case description A 35-year-old man presented with severe new-onset headache, hemiparesis, and focal seizures culminating in deeply altered sensorium. Radiological evaluation showed a large expansile demyelinating lesion in the right cerebral hemisphere. Nasopharyngeal swab COVID reverse transcription-polymerase chain reaction (RT-PCR) was positive. After initial non-response to steroids, the patient responded well to plasma exchange leading to complete recovery. Conclusions This report highlights a case of active severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection presenting with tumefactive demyelination and subsequent response to therapy. It is important to recognize atypical presentations at this juncture as it may be crucial for planning treatment strategies.