Malformation of the Cortical Development Associated with Severe Clusters of Epileptic Seizures

SIMPLE SUMMARY: The malformation of the cortical development is a heterogeneous group of lesions, due to the neural migration and organization disorders, frequently associated with drug-resistant epilepsy in humans. Reports of epileptic seizure activity, due to the malformation of the cortical development in animals, as well as the descriptions of such neural malformations, are very rare. The aim of this case series is to describe the clinical presentation and neuropathological findings of three young animals with a malformation of the cortical development presented with a severe cluster of epileptic seizures that failed to improve with combined antiepileptic therapy, and were humanely euthanized. The first case described is a 3 month old mixed breed dog with a form of focal cortical dysplasia, the second case is a 21 day old Border Collie with a diffuse cortical dysplasia and the third case is a 2.5 month-old domestic cat with lissencephaly. Since, in pediatric neurology, these disorders are commonly associated with epilepsy, we suggest that although there is no direct evidence, these conditions, in our cases, may be accountable for epileptogenesis. ABSTRACT: Three cases of the malformation of the cortical development are described: a mixed breed dog and a Border Collie pup with a focal and diffuse cortical dysplasia, respectively, and a kitten with lissencephaly. All cases presented with intractable epilepsy and were euthanized, due to the cluster of epileptic seizures. The gross examination at necropsy revealed the morphologic alteration of the telencephalic region in two cases. Histopathologically, a disorganization of the cortical lamination with the presence of megalic neurons, was found in the focal cortical dysplasia case. An altered organization of the white and gray matter, with a loss of the normal neuronal distribution and altered neurons, characterized the diffuse cortical dysplasia case. In the lissencephalic cat, there was no recognizable organization of the brain with areas of neuroglial tissue forming nodules in the leptomeningeal space. We strongly support the hypothesis that, as in humans, as well as in the veterinary patients, malformations of the cortical development could be the cause of refractory epilepsy.