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Heterotopic Gray Matter

Last Updated: July 6, 2021

Open Table of Contents: Heterotopic Gray Matter

Figure 1: Phase-sensitive (T1-weighted) inversion recovery (top left) and FLAIR (top right) sequences demonstrate a cluster of nodules along the ependymal surface of the posterior horn of the right lateral ventricle. They have signal characteristics matching gray matter. (Bottom) A T1-weighted image of this patient also demonstrates a band of heterotopic gray matter within the right perirolandic white matter.

Figure 1: Phase-sensitive (T1-weighted) inversion recovery (top left) and FLAIR (top right) sequences demonstrate a cluster of nodules along the ependymal surface of the posterior horn of the right lateral ventricle. They have signal characteristics matching gray matter. (Bottom) A T1-weighted image of this patient also demonstrates a band of heterotopic gray matter within the right perirolandic white matter.

Description

  • Disrupted migration of neurons from periventricular germinal zone to the cortex

Pathology

  • Periventricular nodular type
    • FLNA gene commonly involved on chromosome Xq28
  • Band-like heterotopia/lissencephaly
    • Deletion of LIS1 on chromosome 17p13.3 or DCX on chromosome Xq22.3-q23

Clinical Features

  • Symptoms
    • Young child with variable developmental delays and seizures
  • Age
    • Severe cases present earlier in life
    • Typically present by the third decade of life
  • Gender
    • Male > female
  • Males have worse outcomes

Imaging

  • General
    • Abnormal gray matter nodules or ribbons within the white matter anywhere from ventricles to cortex
  • Modality specific
    • CT and MRI
      • Nonenhancing masses that follow the density or intensity of gray matter on all images
  • Imaging recommendations
    • MRI with contrast
  • Mimic
    • Low-grade gliomas can have a similar appearance but usually do not match gray matter so closely on all MR sequences.

For more information, please see the corresponding chapter in Radiopaedia.

Contributor: Sean Dodson, MD

DOI: https://doi.org/10.18791/nsatlas.v1.03.02.16

References

Barkovich AJ. Morphologic characteristics of subcortical heterotopia: MR imaging study. AJNR Am J Neuroradiol 2000;21:290–295.

Barkovic AJ, Kjos BO. Gray matter heterotopias: MR characteristics and correlation with developmental and neurologic manifestations. Radiology 1992;182:493–499. doi.org/10.1148/radiology.182.2.1732969

Donkol RH, Moghazy KM, Abolenin A. Assessment of gray matter heterotopia by magnetic resonance imaging. World J Radiol 2012;4:90–96. doi.org/10.4329/wjr.v4.i3.90

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