Chronic Rasmussen encephalitis presenting without seizures: A pediatric case report

Rasmussen encephalitis is a rare chronic inflammatory neurological disorder of childhood characterized by progressive unilateral cerebral atrophy and typically associated with intractable focal seizures. We report a 6-year-old boy presenting with progressive right-sided weakness in the absence of clinically evident seizures. Brain MRI performed on a 1.5 T system demonstrated marked asymmetric atrophy of the left cerebral hemisphere, predominantly involving the insular and frontotemporal regions, with associated encephalomalacia, ex-vacuo ventricular dilatation, and ipsilateral Wallerian degeneration, without diffusion restriction or contrast enhancement. In the appropriate clinical context, these findings were suggestive of chronic Rasmussen encephalitis; however, given the absence of EEG and histopathological confirmation, this remains an imaging-based presumptive diagnosis. This case highlights an atypical presentation and emphasizes the importance of MRI in evaluating progressive focal neurological deficits even in the absence of seizures.