Comparison of clinical features and surgical outcome in focal cortical dysplasia type 1 and type 2

•Recent ILAE classification stated focal cortical dysplasia patients with accompanying epileptic lesions as a separate group.•Eighty patients diagnosed with isolated focal cortical dysplasia lesions were examined.•FCD type 1 patients present with late onset epilepsy.•FCD type 2 cases consist of mainly pediatric cases with remarkable features on MRI.

IntroductionRecent ILAE classification defined focal cortical dysplasia (FCD) patients with accompanying epileptic lesions as a separate group. We investigated data of patients with sole FCD lesions regarding long-term seizure outcome and different characteristics of FCD type 1 and type 2 patients.MethodsEighty children and adult patients underwent surgery for FCD were included to the analysis of factors differentiating FCD type 1 and type 2 groups and their effect on long-term outcome.ResultsFCD type 2 patients had earlier epilepsy onset (8.1 vs. 6.1 years. p = 0.019) and underwent surgery younger than type 1 (18.2 vs. 23.7 years. p = 0.034). FCD type 2 patients were more prominently MR positive (77.8% vs. 53.8%. p = 0.029), which increased within FCD type 2 group as patients become younger (p = 0.028). FCD Type 1 lesions showed mostly multilobar extension and FCD type 2 mostly located in frontal lobe. Seizure freedom was achieved in 65.4% of FCD type 1 patients and 70.4% of FCD type 2 patients. Seven patients had permanent de novo neurological deficits. Mean follow-up time was 5.5 years (Range: 1-11 years).ConclusionSurgical intervention in carefully selected patients may facilitate favorable seizure outcome leading to better quality of life. FCD type 1 and type 2 groups present with evident differences, which may promote medical and surgical management of these pathologies.