Chronic T Cell Encephalitis Responsive to Immunotherapy

Chronic encephalitis manifesting as an epilepsy syndrome most commonly presents as Rasmussen's syndrome, usually characterized by epilepsia partialis continua, hemiparesis, and progressive cortical deficits such as aphasia, hemianopia, and cognitive decline. It is characterized by progressive hemispheric cortical atrophy on imaging and is usually seen in childhood. Adult-onset of the syndrome is rare, and only a few cases have been reported with bilateral symptoms. We present a patient with pseudobulbar affect and frontal lobe dysfunction who developed multifocal myoclonic jerks, right hemibody focal motor seizures, and right hemiparesis with bilateral cerebellar signs. Magnetic resonance imaging showed progressive hemispheric atrophy and bilateral features in Positron emission tomography-computed tomography (PET CT). Brain biopsy revealed chronic T-cell infiltrate. We discuss this case as the patient had several features that were atypical for Rasmussen's encephalitis (or syndrome).