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, Maria Thom, Eleonora Aronica, Dawna D. Armstrong, Harry V. Vinters, Andre Palmini, Thomas S. Jacques, Giuliano Avanzini, A. James Barkovich, Giorgio Battaglia, Albert Becker, Carlos Cepeda, Fernando Cendes, Nadia Colombo, Peter Crino, J. Helen Cross, Olivier Delalande, François Dubeau, John Duncan, Renzo GuerriniPhilippe Kahane, Gary Mathern, Imad Najm, Çiǧdem Özkara, Charles Raybaud, Alfonso Represa, Steven N. Roper, Noriko Salamon, Andreas Schulze-Bonhage, Laura Tassi, Annamaria Vezzani, Roberto Spreafico

Research output: Contribution to journalArticlepeer-review

Abstract

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.

Original languageEnglish
Pages (from-to)158-174
Number of pages17
JournalEpilepsia
Volume52
Issue number1
DOIs
Publication statusPublished - Jan 2011

Keywords

  • Cortical dysplasia
  • Epilepsy
  • Hippocampal sclerosis
  • Neuropathology
  • Seizures

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology

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