Clinical features and epileptogenesis of dysembryoplastic neuroepithelial tumor

Introduction Dysembryoplastic neuroepithelial tumor (DNT) frequently causes medically intractable epilepsy. Objective The aim of this study was to investigate the basic mechanism of epileptogenecity of the tumor. Materials and methods Clinicopathological data in 13 cases of DNT and immunohistochemical changes of ionotropic glutamate receptor subunits in the tumor and peritumoral epileptogenic cortex were studied. Conclusions Magnetic resonance imaging combined with electroencephalography (EEG), electrocorticography, and depth-electrode EEG was valuable to localize complicated epileptogenic zones of the patients with DNT. Neuropathological examinations of the peritumoral cerebral cortex presenting abnormal spikes showed different histopathological grades of neuronal migration disorder (NMD). The tumor cells in DNT disclosed increased immunopositivities of N-methyl-D-aspartate receptor 1 (NR1) and NR2A/B, and peritumoral epileptogenic NMD revealed increased immunopositivities of GluR2 and GluR3. The amplification of ionotropic glutamate receptor subunits in the tumor and peritumoral NMD may be the underlying cause of epileptic seizures in DNT patients.