Cortical dysplasia

Overview
Cortical dysplasia is a congenital abnormality where the neurons in an area of the brain failed to migrate in the proper formation in utero. Occasionally neurons will develop that are larger than normal in certain areas. This causes the signals sent through the neurons in these areas to misfire, which sends an incorrect signal. It is commonly found near the cerebral cortex and is associated with seizures and may be associated with some level of developmental delay(s). Instead of using medication to suppress the seizures, surgery is increasingly becoming a popular solution for the problem.

Focal cortical dysplasia is the most common cause of intractable epilepsy in children and is a frequent cause of epilepsy in adults. All forms of focal cortical dysplasia lead to disorganization of the normal structure of the cerebral cortex. Focal cortical dysplasia associated with enlarged cells is known as FCDIIB. The enlarged cells are called balloon cells for their large elliptical shape, displaced nucleus, and lack of dendrites or axons. The developmental origin of balloon cells is unknown although they are believed to be derived from neuronal or glial progenitor cells. Balloon cells are similar in structure to giant cells in the disorder tuberous sclerosis complex. Other large cells known as cytomegalic neurons or dysplastic neurons exhibit an enlarged cell body but clear axons and dendrites. It is widely hypothesized that balloon cells and dysplastic neurons contribute to seizures in patients with cortical dysplasia.