BACKGROUND: Early cerebral injury has a close relationship with epilepsy and focal cortical dysplasia IIId. We investigated children with focal cortical dysplasia Illd who underwent surgery for epilepsy. METHODS: We selected 49 patients from among 260 pediatric patients who had undergone epilepsy surgery, analyzing their clinical materials and pathology data. The selected patients had been followed for more than two years. RESULTS: The 49 patients were divided into seven groups based on different early brain injuries. There was a significant difference (P < 0.05) between Engel class I ratio of cerebral hemorrhage group (84.6%) and that of central nervous system infection group (42.1%) in two to eight years follow-up. The patients with prior cerebral hemorrhage had a wider scope (P < 0.05) of brain damage than those in the brain infection and febrile convulsion groups. Secondary polymicrogyria commonly existed. Neuron islands were located adjacent to polymicrogyria in cerebral hemorrhage and brain trauma patients, and missing neuronal laminations beside the polymicrogyria was noted in others. CONCLUSIONS: In children with focal cortical dysplasia Illd, individuals with cerebral hemorrhage within the perinatal period exhibited a wider range of brain lesions, while the postoperative follow-up outcome was better. Secondary polymicrogyria existed along with focal cortical dysplasia Illd and is related to the developmental lesion. The processes of secondary polymicrogyria caused by different early brain injuries might be different. (C) 2018 Elsevier Inc. All rights reserved.