Blumcke classification of focal cortical dysplasia

Assoc Prof Frank Gaillard ◉ ◈ et al.

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 classifications system 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 classifications 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
- 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

References

Malformations of the central nervous system

malformations of cortical development
- abnormal cell proliferation or apoptosis
  - abnormal brain size
    - microcephaly
      - with normal to simplified cortical pattern
      - microcephaly with lissencephaly
      - microcephaly with extensive polymicrogyria
    - macrocephalies (megalencephaly/macrocephaly)
  - abnormal cell proliferation
    - non-neoplastic
      - cortical hamartomas of tuberous sclerosis
      - hemimegalencephaly
      - focal cortical dysplasia (Type I and Type IIb)
        
        Palmini classification (2004)
        
        Barkovich classification (2005)
        
        Blumcke classification (2011)
    - neoplastic
  - abnormal neuronal migration
    - lissencephaly
      - lissencephaly type I: subcortical band heterotopia spectrum (band heterotopia): undermigration
      - lissencephaly type II (cobblestone complex)
    - heterotopia: ectopic migration
      - subependymal heterotopia
      - subcortical heterotopia (not including band heterotopia)
      - marginal glioneuronal heterotopia
  - abnormal cortical organization
    - mild malformations of cortical development (previously microdysgenesis)
    - polymicrogyria and schizencephaly
      - bilateral polymicrogyria syndromes
      - schizencephaly
    - focal cortical dysplasia (Type IIa)
- not otherwise classified
  - malformations secondary to inborn errors of metabolism
    - mitochondrial and pyruvate metabolic disorders
    - peroxisomal disorders
  - other unclassified malformations
    - sublobar dysplasia
midline abnormalities of the brain
- absent septum pellucidum
- cephaloceles
- midline nasal region lesions
  - nasal dermoid
  - nasal glioma
  - nasal dermal sinus
- cerebral hemispheres
  - holoprosencephaly/septo-optic dysplasia spectrum
    - septo-optic dysplasia
    - lobar holoprosencephaly
    - semilobar holoprosencephaly
    - alobar holoprosencephaly
    - middle interhemispheric variant/syntelencephaly
- corpus callosum
  - corpus callosum agenesis /dysgenesis
    - racing car sign
- intracranial lipoma
malformations of the cerebellum
- cerebellar hypoplasia
  - focal hypoplasia
  - generalized hypoplasia
    - with enlarged fourth ventricle
      - Dandy-Walker continuum
        
        Dandy-Walker malformation
        
        Dandy-Walker variant
        isolated inferior vermian hypoplasia
        
        Blake’s pouch cyst
        
        fourth ventriculocoele
    - normal fourth ventricle
      - with normal pons
      - with small pons
        normal foliation
        
        pontocerebellar hypoplasias of Barth, types I and II
        
        cerebellar hypoplasias, not otherwise specified
- cerebellar dysplasia
  - focal dysplasia
    - isolated vermian dysplasia
      - molar tooth malformations including Joubert syndrome
      - rhombencephalosynapsis
    - isolated hemispheric dysplasia
      - focal cerebellar cortical dysplasias/heterotopia
      - Lhermitte-Duclos-Cowden syndrome
  - generalized dysplasia
    - congenital muscular dystrophies
    - cytomegalovirus
    - lissencephaly with RELN mutation
    - lissencephaly with agenesis of corpus callosum and cerebellar dysplasia
    - associated with diffuse cerebral polymicrogyria
    - diffusely abnormal foliation
malformations of the brainstem