The clinicopathologic spectrum of focal cortical dysplasias: a consensus classification proposed by an ad hoc Task Force of the ILAE Diagnostic Methods Commission.

Ingmar Blümcke (1) , Maria Thom (2) , Eleonora Aronica (3) , Dawna D. Armstrong (4) , Harry V. Vinters (5) , Andre Palmini (6) , Thomas S. Jacques (7) , Giuliano Avanzini (8) , James A. Barkovich (9) , Giorgio Battaglia (10) , Albert J. Becker (11) , Carlos Cepeda (12) , Fernando Cendes (13) , Nadia Colombo (14) , Crino Peter (15) , Helen J. Cross (16) , Olivier Delalande (17) , François Dubeau (18) , John Duncan (19) , Renzo Guerrini (20) , Philippe Kahane (21, 22) , Gary Mathern (23) , Imad Najm (24) , Ciğdem Ozkara (25) , Charles Raybaud (26) , Alfonso Represa (27) , Steven N. Roper (28) , Noriko Salamon (29) , Andreas Schulze-Bonhage (30) , Laura Tassi (31) , Annamaria Vezzani (32) , Roberto Spreafico (8)

1 Department of Neuropathology
2 Department of Neuropathology
3 Department of (Neuro)Pathology, Academic Medisch Centrum
4 Texas Children's Hospital [Houston, USA]
5 Departments of Pathology and Laboratory Medicine (Neuropathology) and Neurology
6 Servico de Neurologia
7 ICH - UCL-Institute of Child Health
8 Department of Epilepsy Clinic and Experimental Neurophysiology
9 Department of Neuroradiology
10 Molecular Neuroanatomy and Pathogenesis Unit
11 Department of Neuropathology
12 IDDRC - Intellectual and Developmental Disabilities Research Center
13 Department of Neurology
14 Department of Neuroradiology
15 PENN Epilepsy Center
16 The Prince of Wales's Chair of Childhood Epilepsy
17 Service de Neurochirurgie Pediatrique
18 Montreal Neurological Institute and Hospital
19 Department of Clinical and Experimental Epilepsy
20 Pediatric Neurology Unit and Laboratories
21 GIN - Grenoble Institut des Neurosciences
22 Département de neurologie
23 Departments of Neurosurgery, Psychiatry and Behavioral Science
24 Neurological Institute
25 Department of Neurology
26 Division of Neuroradiology
27 INMED - INSERM U1249 - Institut de Neurobiologie de la Méditerranée [Aix-Marseille Université]
28 Department of Neurosurgery
29 Departement of Radiology
30 Epilepsy Centre
31 Centre « Claudio-Munari » pour la chirurgie de l'épilepsie et du Parkinson
32 Department of Neuroscience

PURPOSE:   Focal cortical dysplasias (FCD) are localized regions of malformed cerebral cortex and are very frequently associated with epilepsy in both children and adults. A broad spectrum of histopathology has been included in the diagnosis of FCD. An ILAE task force proposes an international consensus classification system to better characterize specific clinicopathological FCD entities. METHODS: Thirty-two Task Force members have reevaluated available data on electroclinical presentation, imaging, neuropathological examination of surgical specimens as well as postsurgical outcome. KEY FINDINGS: The ILAE Task Force proposes a three-tiered classification system. FCD Type I refers to isolated lesions, which present either as radial (FCD Type Ia) or tangential (FCD Type Ib) dyslamination of the neocortex, microscopically identified in one or multiple lobes. FCD Type II is an isolated lesion characterized by cortical dyslamination and dysmorphic neurons without (Type IIa) or with balloon cells (Type IIb). Hence, the major change since a prior classification represents the introduction of FCD Type III, which occurs in combination with hippocampal sclerosis (FCD Type IIIa), or with epilepsy-associated tumors (FCD Type IIIb). FCD Type IIIc is found adjacent to vascular malformations, whereas FCD Type IIId can be diagnosed in association with epileptogenic lesions acquired in early life (i.e., traumatic injury, ischemic injury or encephalitis). SIGNIFICANCE: This three-tiered classification system will be an important basis to evaluate imaging, electroclinical features, and postsurgical seizure control as well as to explore underlying molecular pathomechanisms in FCD.

Ingmar Blümcke, Maria Thom, Eleonora Aronica, Dawna D. Armstrong, Harry V. Vinters, et al.. The clinicopathologic spectrum of focal cortical dysplasias: a consensus classification proposed by an ad hoc Task Force of the ILAE Diagnostic Methods Commission.. Epilepsia, 2011, 52 (1), pp.158-74. ⟨10.1111/j.1528-1167.2010.02777.x⟩. ⟨inserm-00592131⟩