The overall appearance of unilateral hemispheric cortical atrophy on MRI is suggestive of Rasmussen encephalitis.

Electroencephalography (EEG) showed focal slowing and interictal discharges in the right temporal area. The patient was initially treated for presumed Rasmussen encephalitis with anticonvulsants, a monoclonal antibody, and intravenous immunoglobulin.

A right-sided hemispherectomy was later performed due to ongoing seizures refractory to medical therapy. Histological analysis of resected brain tissue confirmed a diagnosis of Rasmussen encephalitis.

It should be noted that histological review also revealed mesial temporal sclerosis of the right hippocampus.

The patient experienced no further seizures following the right-sided hemispherectomy.