title: New classification of focal cortical dysplasia: application to practical diagnosis.
abstract: OBJECTIVE
  Malformation of cortical development (MCD) is a well-known cause of drug-resistant epilepsy and focal cortical dysplasia (FCD) is the most common neuropathological finding in surgical specimens from drug-resistant epilepsy patients. Palmini's classification proposed in 2004 is now widely used to categorize FCD. Recently, however, Blumcke et al. recommended a new system for classifying FCD in 2011.
  
  
  METHODS
  We applied the new classification system in practical diagnosis of a sample of 117 patients who underwent neurosurgical operations due to drug-resistant epilepsy at Severance Hospital in Seoul, Korea.
  
  
  RESULTS
  Among 117 cases, a total of 16 cases were shifted to other FCD subtypes under the new classification system. Five cases were reclassified to type IIIa and five cases were categorized as dual pathology. The other six cases were changed within the type I category.
  
  
  CONCLUSIONS
  The most remarkable changes in the new classification system are the advent of dual pathology and FCD type III. Thus, it will be very important for pathologists and clinicians to discriminate between these new categories. More large-scale research needs to be conducted to elucidate the clinical influence of the alterations within the classification of type I disease. Although the new FCD classification system has several advantages compared to the former, the correlation with clinical characteristics is not yet clear.
authors.affiliation: Department of Pathology, Yonsei University College of Medicine.
authors.forename: Yoon-Sung
authors.initials: YS
authors.lastname: Bae
authors.affiliation: Division of Pediatric Neurology, Department of Pediatrics, Pediatric Epilepsy Clinic, Severance Children's Hospital, Epilepsy Research Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hoon-Chul
authors.initials: HC
authors.lastname: Kang
authors.affiliation: Division of Pediatric Neurology, Department of Pediatrics, Pediatric Epilepsy Clinic, Severance Children's Hospital, Epilepsy Research Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Heung Dong
authors.initials: HD
authors.lastname: Kim
authors.affiliation: Department of Pathology, Yonsei University College of Medicine.
authors.forename: Se Hoon
authors.initials: SH
authors.lastname: Kim
keywords: Epilepsy; Focal cortical dysplasia; Malformations of cortical development