Morphological criteria for the diagnosis of focal cortical dysplasias in patients with pharmacoresistant epilepsy: a literature review

Medical Review (Med. pregled), 2023, 59(4), 12-22.

D. Metodiev

Neuropathological Laboratory, University Hospital „Sv. Ivan Rilski“, Sofia
Department of Clinical Pathology, Nadezhda Women’s Health Hospital, Sofia

Abstract. Focal cortical dysplasias are a group of heterogeneous brain morphological alterations that can predispose to the development of pharmacoresistant epilepsy. This work reviews the literature concerning the morphological substrate found in the brains of patients operated for pharmacoresistant epilepsy. Cortical dysplasias include different types of epileptogenic changes. Type I cortical dysplasia is characterized by cortical dyslamination with the presence of changes in the histoarchitectonics of the cerebral cortex. Type II includes cases with cortical dyslamination and the presence of dysmorphic neurons, and balloon cells. Type III is diagnosed in combination with other principal epileptogenic lesions (hippocampal sclerosis, tumors, vascular malformations, inflammations, or others). The revised International League against. Epilepsy classification of 2022 includes new categories – with predisposing cerebral white matter involvement. These are mild malformation of cortical development and cortical malformation with oligodendroglial hyperplasia. There is also a category that includes all cases in which it is not possible to accurately identify the type of lesion. Although the histopathological characteristics of the various types of focal dysplasias are well known, their etiologic and pathogenetic features remain incompletely understood. The identification of characteristic molecular genetic alterations in some of the cases provides a chance for new therapeutic approaches, which have an essential role in cases for which comprehensive surgery is not possible.

Key words: focal cortical dysplasias, pharmacoresistant epilepsy, tumors, mild malformation of cortical development

Address for correspondence: Dimitar Metodiev, MD, e-mаil: dimitarmetodievvv@gmail.com