Subcortical heterotopia

Last revised by Mohamed Saber on 10 Nov 2022

Subcortical heterotopia is a form of nodular grey matter heterotopia. They can be divided into:

  • nodular form: extend from the ventricle into the white matter
  • curvilinear form: extend from the cortex into the underlying white matter
  • mixed form

The term laminar heterotopia is sometimes used ambiguously to refer to some of these patients 4. It is important to note that these patients should not be confused with lissencephaly type I-subcortical band heterotopia spectrum which is distinct on both imaging and at an underlying genetic level. 

Epilepsy is very common and typically presents in childhood 3. It is usually associated with variable developmental delay 3

Subcortical heterotopias are continuous with the overlying cortex or underlying ventricle 2 and are associated with severe abnormalities of the involved hemisphere, characterized by 1:

  • diffuse reduction in size of the hemisphere
  • distorted ventricles
  • diminished and abnormal white matter
  • thinned overlying cortex with shallow sulci
  • distorted basal ganglia

These features are helpful in distinguishing this entity from subependymal grey matter heterotopia and lissencephaly type I-subcortical band heterotopia spectrum

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Cases and figures

  • Case 1: subcortical heterotopia
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  • Case 2: with absent septum pellucidum
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  • Case 3
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