Abstracts

Rationale: Various pre/perinatal adverse events have been reported to have a pathogenetic role in focal cortical dysplasia (FCD). However, no data are available regarding the prevalence and significance of this association. The present study aims to analyze a cohort of children with significant pre/perinatal risk factors and histologically proven FCD. Our goal was to identify distinctive characteristics of epileptic and neurological syndromes in these patients in order to achieve earlier diagnosis and enhance surgical management. Methods: We retrospectively evaluated a surgical series of 200 patients with histologically confirmed mild malformations of cortical development (mMCD) or FCD. Subjects with other migrational disorders such as tuberous sclerosis complex, polymicrogyria and nodular heterotopia were not included. Patients with pre/perinatal risk factors were identified on the basis of analysis of anamnestic data and MRI findings. Electro-clinical, imaging, neuropsychological, surgical, histopathological and seizure outcome data were reviewed. Results: Pre/perinatal risk factors occurred in 12.5% of children in our series (N=25). They included prematurity (N=8), asphyxia (N=7), bleeding (N=6), hydrocephalus (N=7) and stroke (N=4). Mean age at seizure onset was 1.64 years. Seizures occurred daily in 88% of cases. 88% of subjects had abnormal neurological exam. Mental retardation was identified in 89% of patients. Unequivocal consequences of pre/perinatal insults were present on MRI in 88% of subjects. MRI findings typical for cortical malformations were detected in 74% of patients. Eight cases had unilobar resections, seven had multilobar resections and ten had hemispherectomy. Sixteen subjects had at least two years of postoperative follow-up; 50% were seizure-free. mMCD type II was histopathologically identified in five, FCD type Ia in 15, FCD type Ib in six and FCD type IIb in two subjects. Conclusions: Pre/perinatal adverse events frequently occur in patients with FCD. They are significantly associated with histopathologically “milder” forms of cortical malformation (mMCD and FCD type I) than FCD type II. Cortical malformations could play an important role in the pathogenesis of epilepsy and neurological deficits in children with acquired neonatal encephalopathies. Supported by Grant IGA NR/8843-4 and VZ 00000064203.