Semin Neurol 2015; 35(03): 201-208
DOI: 10.1055/s-0035-1552617
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Focal Cortical Dysplasia

Peter B. Crino
1   Department of Neurology, Shriners Hospital Pediatric Research Center and Temple University, Philadelphia, Pennsylvania
› Author Affiliations
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Publication History

Publication Date:
10 June 2015 (online)

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Abstract

Focal cortical dysplasias are common malformations of cerebral cortical development and are highly associated with medically intractable epilepsy. They have been classified into neuropathological subtypes (type Ia, Ib, IIa, IIb, and III) based on the severity of cytoarchitectural disruption—tangential or radial dispersion, or loss of laminar structure—and the presence of unique cells types such as cytomegalic neurons or balloon cells. Most focal cortical dysplasias can be identified on neuroimaging and many require resective epilepsy surgery to cure refractory seizures. The pathogenesis of focal cortical dysplasias remains to be defined, although there is recent evidence to suggest that focal cortical dysplasias arise from de novo somatic mutations occurring during brain development. Some focal cortical dysplasia subtypes show a link to the mammalian target of rapamycin signaling cascade; this has now extended to other cortical malformations, including hemimegalencephaly.

Note

There has been a recent publication reporting somatic mutations in MTOR in FCDIIa and FCDIIb (Lim JS, Kim WI, Kang HC, et al. Brain somatic mutations in MTOR cause focal cortical dysplasia type II leading to intractable epilepsy. Nat Med 2015;21(4):395–400).