title: International consensus classification of hippocampal sclerosis in temporal lobe epilepsy: a Task Force report from the ILAE Commission on Diagnostic Methods.
abstract: Hippocampal sclerosis (HS) is the most frequent histopathology encountered in patients with drug-resistant temporal lobe epilepsy (TLE). Over the past decades, various attempts have been made to classify specific patterns of hippocampal neuronal cell loss and correlate subtypes with postsurgical outcome. However, no international consensus about definitions and terminology has been achieved. A task force reviewed previous classification schemes and proposes a system based on semiquantitative hippocampal cell loss patterns that can be applied in any histopathology laboratory. Interobserver and intraobserver agreement studies reached consensus to classify three types in anatomically well-preserved hippocampal specimens: HS International League Against Epilepsy (ILAE) type 1 refers always to severe neuronal cell loss and gliosis predominantly in CA1 and CA4 regions, compared to CA1 predominant neuronal cell loss and gliosis (HS ILAE type 2), or CA4 predominant neuronal cell loss and gliosis (HS ILAE type 3). Surgical hippocampus specimens obtained from patients with TLE may also show normal content of neurons with reactive gliosis only (no-HS). HS ILAE type 1 is more often associated with a history of initial precipitating injuries before age 5 years, with early seizure onset, and favorable postsurgical seizure control. CA1 predominant HS ILAE type 2 and CA4 predominant HS ILAE type 3 have been studied less systematically so far, but some reports point to less favorable outcome, and to differences regarding epilepsy history, including age of seizure onset. The proposed international consensus classification will aid in the characterization of specific clinicopathologic syndromes, and explore variability in imaging and electrophysiology findings, and in postsurgical seizure control.
authors.affiliation: Department of Neuropathology, University Hospital Erlangen, Erlangen, Germany.
authors.forename: Ingmar
authors.initials: I
authors.lastname: Blümcke
authors.forename: Maria
authors.initials: M
authors.lastname: Thom
authors.forename: Eleonora
authors.initials: E
authors.lastname: Aronica
authors.forename: Dawna D
authors.initials: DD
authors.lastname: Armstrong
authors.forename: Fabrice
authors.initials: F
authors.lastname: Bartolomei
authors.forename: Andrea
authors.initials: A
authors.lastname: Bernasconi
authors.forename: Neda
authors.initials: N
authors.lastname: Bernasconi
authors.forename: Christian G
authors.initials: CG
authors.lastname: Bien
authors.forename: Fernando
authors.initials: F
authors.lastname: Cendes
authors.forename: Roland
authors.initials: R
authors.lastname: Coras
authors.forename: J Helen
authors.initials: JH
authors.lastname: Cross
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Jacques
authors.forename: Philippe
authors.initials: P
authors.lastname: Kahane
authors.forename: Gary W
authors.initials: GW
authors.lastname: Mathern
authors.forename: Haijme
authors.initials: H
authors.lastname: Miyata
authors.forename: Solomon L
authors.initials: SL
authors.lastname: Moshé
authors.forename: Buge
authors.initials: B
authors.lastname: Oz
authors.forename: Çiğdem
authors.initials: Ç
authors.lastname: Özkara
authors.forename: Emilio
authors.initials: E
authors.lastname: Perucca
authors.forename: Sanjay
authors.initials: S
authors.lastname: Sisodiya
authors.forename: Samuel
authors.initials: S
authors.lastname: Wiebe
authors.forename: Roberto
authors.initials: R
authors.lastname: Spreafico
mesh_terms: D026683:Advisory Committees; D017668:Age of Onset; D004833:Epilepsy, Temporal Lobe / Q000145:classification / Q000150:complications / Q000473:pathology; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006624:Hippocampus / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D054220:Malformations of Cortical Development / Q000473:pathology; D009474:Neurons / Q000473:pathology; D019370:Observation; D012598:Sclerosis / Q000145:classification / Q000473:pathology
chemical_list: D005904:Glial Fibrillary Acidic Protein
keywords: Brain; Epileptology; Hippocampus; Neurology; Neuropathology; Seizures