Terminology and classification of the cortical dysplasias

Background: There have been difficulties in achieving a uniform terminology in the literature regarding issues of classification with respect to focal cortical dysplasias (FCDs) associated with epilepsy. Objectives: To review and refine the current terminology and classification issues of potential clinical relevance to epileptologists, neuroradiologists, and neuropathologists dealing with FCD. Methods: A panel discussion of epileptologists, neuropathologists, and neuroradiologists with special expertise in FCD was held. Results: The panel proposed 1) a specific terminology for the different types of abnormal cells encountered in the cerebral cortex of patients with FCD; 2) a reappraisal of the different histopathologic abnormalities usually subsumed under the term "microdysgenesis," and suggested that this terminology be abandoned; and 3) a more detailed yet straightforward classification of the various histopathologic features that usually are included under the heterogeneous term of "focal cortical dysplasia." Conclusion: The panel hopes that these proposals will stimulate the debate toward more specific clinical, imaging, histopathologic, and prognostic correlations in patients with FCD associated with epilepsy.