[Surgical Pathology of Adulthood Epilepsy]

Epilepsy may be the consequence of a wide range of disorders affecting the brain, including tumors and non-neoplastic lesions. A broad spectrum of structural brain lesions can be observed in epileptogenic brain tissue specimens surgically resected from patients with drug-resistant focal epilepsies. These include hippocampal sclerosis (HS), low-grade epilepsy-associated neuroepithelial tumors (LEAT), malformations of cortical development (MCD), vascular malformations, dual pathology, glial scar, and encephalitis, as well as no lesion. HS, LEAT, and MCD constitute over 75% of all surgical pathologies of epilepsy. International consensus histological classifications of HS and focal cortical dysplasia (FCD) have been proposed by the International League Against Epilepsy (ILAE), based on agreement on the importance of defining a histopathological classification system that has a reliable clinicopathological correlation. These ILAE classifications are likely to facilitate future clinicopathological studies. The validity and usefulness of the ILAE classifications should be further evaluated for future revision for clinicopathologically meaningful classification with better interobserver agreement, particularly for FCD types I and III. Although it is still an emerging field of neuropathology, surgical pathology of epilepsy will likely play an important role in unraveling the pathogenesis and epileptogenesis of structural brain lesions, thereby contributing to the future precision medicine.