Dysembryoplastic neuroepithelial tumor in the insular cortex. Three dimensional magnetoencephalographic localization of epileptic discharges.

A case of dysembryoplastic neuroepithelial tumor in the left insular cortex manifesting with intractable seizures is presented. The multichannel magnetoencephalography (MEG) localized equivalent current dipoles of epileptic discharges at the cerebral cortex adjacent to the tumor. The total removal of the tumor resulted in complete disappearance of seizures. This case demonstrated that multichannel MEG was useful in the three-dimensional localization of irritative zone in the concealed cortices such as inside the sylvian fissure.