Fact-sheet: Cortical dysplasia
Updated on 09/17/2021 at 12:16 PM
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Definition
Cortical malformation often responsible for epilepsy potentially refractory to any treatment.
They are generated by a disturbance in one of the stages of cortical formation:
- Cell proliferation
- Neuronal migration
- Cortical organization
They are frequently associated with other malformations within a syndromic setting.
Clinical features
Depends on the type and location of the abnormality, but the following are frequently found:
- Epilepsy +++, often pharmacoresistant
- Mental retardation
- Deficit: hemiparesis, hemianopsia
Also depends on whether or not it is syndromic.
MRI
MRI allows a precise assessment of the lesions:
- Location (involvement of hippocampal structures?)
- Presence of heterotopia
- Lissencephaly
- Schizencephaly
- Appearance of the ventricular system
Also allows guidance of surgery in cases of pharmacoresistant epilepsy.
Management
Treatment of epilepsy; if pharmacoresistant, surgery may be considered.
Classification
Classification of cortical malformations (after Barkovich et al)
1) Malformation due to an abnormality of neuronal and glial proliferation or apoptosis
A. Decreased proliferation/increased apoptosis: Microcephalies
- Microcephaly with normal or thin cortex
- Microlissencephaly (extreme microcephaly with thin cortex)
- Microcephaly with polymicrogyria/cortical dysplasia
B. Increased proliferation/decreased apoptosis (normal cell types): Megalencephalies
C. Abnormal proliferation (abnormal cell types)
1. Nontumoral
- Cortical hamartoma of tuberous sclerosis of Bourneville
- Focal cortical dysplasia with balloon cells (type II cortical dysplasia)
- Hemimegalencephaly
- Transcerebral cortical dysplasia
2. Tumoral
- Dysembryoplastic neuroepithelial tumor (proliferation of neuronal, oligodendroglial, and
astrocytic cell lines)
- Ganglioglioma (glial predominance)
- Gangliocytoma (neuronal predominance)
2) Malformation due to an abnormality of neuronal migration
A. Classic lissencephaly (type I) and band heterotopia spectrum
B. Cobblestone lissencephaly (type II)
1. Syndrome with congenital muscular dystrophy
2. Syndrome without muscular involvement
C. Nodular gray matter heterotopia
- Subependymal (periventricular)
- Subcortical (other than band heterotopia)
- Marginal glioneuronal
3) Malformations due to an abnormality of cortical organization
A. Polymicrogyria and Schizencephaly
- Bilateral polymicrogyria
- Schizencephaly
- Polymicrogyria with other cerebral malformations or abnormalities
- Polymicrogyria or schizencephaly associated with multiple congenital anomalies or mental retardation
B. Cortical dysplasia without balloon cells
C. Microdysgenesis
4) Unclassified cortical malformations
