Recent advances in the neuropathology of focal lesions in epilepsy.

This review addresses the main neuropathologic advances that have been made over recent years in the study of focal lesions in patients with epilepsy undergoing surgical treatment. There have been revisions and simplifications to the classification of focal cortical dysplasias. Hippocampal sclerosis is a well-characterized lesion but further pathologic studies have explored its possible relationship to temporal lobe developmental lesions, ongoing neurogenesis and mechanisms of its epileptogenicity. The important contribution of astrocytes to epileptogenesis is also unfolding and is briefly discussed, as are the possible cellular mechanisms of drug resistance.