Hemimegalencephaly. A Case Report

Hemimegalencephaly is a disorder of neuronal proliferation that causes an overgrowth of all or part of a cerebral hemisphere. Its pathogenesis is still unknown. We present the case of an adult patient with a history of childhood-onset epilepsy, which was refractory to medical treatment and associated with moderate mental retardation. He was admitted to the hospital for seizure control. Magnetic resonance imaging showed hemispheric asymmetry with enlarged right cerebral hemisphere and poor gray-white matter differentiation. The objective of this paper is to present a rare cause of epilepsy that is usually diagnosed during childhood. Hemimegalencephaly should be suspected in cases of early onset of difficult-to-control epilepsy, especially when associated with macrocephaly and delayed psychomotor development. Timely indication for neuroimaging allows establishing the diagnosis and providing other treatment options. (author)