International consensus classification of hippocampal sclerosis in temporal lobe epilepsy: A Task Force report from the ILAE Commission on Diagnostic Methods |
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| Authors: | Ingmar Blümcke Maria Thom Eleonora Aronica Dawna D Armstrong Fabrice Bartolomei Andrea Bernasconi Neda Bernasconi Christian G Bien Fernando Cendes Roland Coras J Helen Cross Thomas S Jacques Philippe Kahane Gary W Mathern Haijme Miyata Solomon L Moshé Buge Oz Çiğdem Özkara Emilio Perucca Sanjay Sisodiya Samuel Wiebe Roberto Spreafico |
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| Institution: | 1. Department of Neuropathology, University Hospital Erlangen, , Erlangen, Germany;2. Department of Neuropathology, Institute of Neurology, University College London, , London, United Kingdom;3. Department of (Neuro)Pathology, Academic Medisch Centrum (AMC), Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, , Amsterdam, The Netherlands;4. SEIN –Stichting Epilepsie Instellingen Nederland, , Heemstede, The Netherlands;5. Baylor College of Medicine and Texas Children's Hospital, , Houston, Texas, U.S.A;6. INSERM U1006, Brain Dynamic Institute, Université de la Méditerranée, , Marseille, France;7. Montreal Neurological Institute, McGill University, , Montreal, Québec, Canada;8. Epilepsy Center Bethel, Hospital Mara, , Bielefeld, Germany;9. Department of Neurology, University of Campinas, , Campinas, Brazil;10. The Prince of Wales's Chair of Childhood Epilepsy UCL‐Institute of Child Health, Great Ormond Street Hospital for Children & National Centre for Young People with Epilepsy, , London, United Kingdom;11. UCL‐Institute of Child Health and Great Ormond Street Hospital for Children, NHS Foundation Trust, , London, United Kingdom;12. Neurology Department and INSERM U836, Grenoble University Hospital, , Grenoble, France;13. Departments of Neurosurgery, and Psychiatry & BioBehavioral Medicine, David Geffen School of Medicine, Mattel Children's Hospital, University of California, , Los Angeles, California, U.S.A;14. Department of Neuropathology, Research Institute for Brain and Blood Vessels‐Akita, , Akita, Japan;15. Saul R. Korey Department of Neurology, Epilepsy Management Center, , Bronx, New York, U.S.A;16. Dominick P. Purpura Department of Neuroscience, , Bronx, New York, U.S.A;17. Department of Pediatrics, Albert Einstein College of Medicine, , Bronx, New York, U.S.A;18. Department of Pathology, Cerrahpasa Medical Faculty, Istanbul University, , Istanbul, Turkey;19. Department of Neurology, Cerrahpasa Medical Faculty, Istanbul University, , Istanbul, Turkey;20. Department of Pharmacology, University of Pavia, , Pavia, Italy;21. Clinical Trial Centre and Neuropharmacology Unit, National Institute of Neurology IRCCS C. Mondino Foundation, , Pavia, Italy;22. Institute of Neurology, University College London, Queen Square, , London, United Kingdom;23. Departments of Clinical Neurosciences, Community Health Sciences, and Paediatrics, Faculty of Medicine, University of Calgary, , Calgary, Alberta, Canada;24. Department of Epilepsy Clinic and Experimental Neurophysiology, IRCCS Foundation Neurological Institute “Carlo Besta”, , Milan, Italy |
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| 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. |
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| Keywords: | Brain Hippocampus Neurology Epileptology Neuropathology Seizures |
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