Blumcke classification of focal cortical dysplasia

Blumcke et al. proposed the most recent (2011) ² and now widely adopted consensus classification system for focal cortical dysplasia, which shares many features with the previously described classification systems by Palmini (2004) and Barkovich (2005). 

Unfortunately, as is the case with many classification systems that have developed in parallel with numerous iterations and revisions, there is significant overlap between the various classification systems with the same terminology used slightly differently. 

• type I: focal cortical dysplasia with abnormal cortical lamination

  • a: radial cortical lamination

  • b: tangential 6-layer cortical lamination

  • c: radial and tangential cortical lamination

• type II: focal cortical dysplasia with dysmorphic neurons (Taylor dysplasia)

  • a: without balloon cells

  • b: with balloon cells

• type III: architectural distortion of cortical layer

  • a: in temporal lobe with hippocampal atrophy

  • b: adjacent to glial or glioneuronal tumor

  • c: adjacent to vascular malformation

  • d: adjacent to other lesions acquired in early childhood

In 2022 the International League Against Epilepsy (ILAE) task force, released a proposed consensus classification of focal cortical dysplasia which builds upon the exiting Blumcke classification.

It adds two new categories ³:

1. white matter

   1. mild malformations of cortical development with excessive heterotopic neurons

   2. mild malformations of cortical development with oligodendroglial hyperplasia

2. no definite FCD on histopathology

It also proposes an integrated multi-layered classification that adds genetic and neuroimaging information, coming to an integrated diagnosis ³.