Malformations du développement cortical : quelles stratégies ?

Abstract

Malformations of cortical development (MCD) correspond to a broad spectrum of cerebral lesions resulting from cortical development abnormalities during embryogenesis. They are frequently associated with drug-resistant epilepsy as well as more or less severe neurological and cognitive deficits. Diagnosis of MCD has greatly improved with the progress in contemporary imaging techniques, and patients with cryptogenic epilepsy are increasingly recognized as having MCD. Current classifications based on the combination of clinical, imaging, genetic and pathological data allow analysis of homogeneous patient series and optimal therapeutic strategies. Successful surgical treatment can be proposed to patients with focal lesions such as focal cortical dysplasia or tumors associated with cortical dysplasia (dysembryoplastic neuroepithelial tumors and gangliogliomas). Favorable outcome can also be obtained in some diffuse cases such as tuberous sclerosis, periventricular heterotopia and polymicrogyria. Invasive monitoring, especially stereoelectroencephalography (SEEG), has proved to be useful in determining the organization of the epileptogenic zone in each MCD type and planning cortical resections. Moreover, establishing correlations between neurophysiological data, imaging and pathological findings has allowed surgery without previous invasive procedures in the majority of focal MCD types; however, intracranial recordings remain necessary in case of more diffuse MCD.