What is the fate of disconnected brain tissue in a child with Rasmussen syndrome? A case report.

We describe a case of Rasmussen syndrome in a 7-year-old boy, presenting with epilepsia partialis continua, hemiplegia, and progressive mental deterioration. The initial MRI examination was normal, followed by progressive left hemispheric cortical atrophy and abnormal high signal intensity over the left occipital, parietal, and cingulate gyral areas over an 18-month period. On the basis of the clinical diagnosis and biopsy findings of Rasmussen syndrome, functional hemispherectomy was carried out at 7.5 years of age with alleviation of clinical seizures for the following 44 months. The follow-up MRI demonstrated atrophic changes involving the remaining left hemisphere with increased signal and cortical volume loss, as well as the absence of abnormal signal in the right hemisphere at 10 years of age. Our MRI findings are consistent with the progression of Rasmussen syndrome in the ipsilateral hemisphere even after functional-hemispherectomy without clinical seizures.