Abstracts

Dysembryoplastic neuroepithelial tumors (DNET) are benign, localized lesions producing localization related epilepsy. Although excellent seizure outcomes are typically expected following surgical resection of focal, benign lesions, some reports suggest that this may not be the case with DNETs, which may exhibit complex and often multifocal epileptogenesis. We report on the characteristics and surgical outcome of patients with this condition., This is a retrospective cohort of seven patients with localization related epilepsy associated with histopathologically demonstrated DNETs. We assessed clinical, electrographic and surgical features, We were particularly interested in the level of congruence of EEG and MRI data and the need for intracranial recordings. We evaluated seizure outcomes at last follow-up. Results are expressed as means and proportions with corresponding 95% confidence intervals. We present an index case to illustrate the complexity of epileptogenesis in DNET., Seven patients were studied, of whom three (43%) were females. Their mean age was 17.7 (range: 9-33). Five patients (71 %) had partial seizures (PS) with or without generalized tonic clonic seizures (GTCS); two patients (29%) had only PS. None had a tendency to status epilepticus. DNETs were located in the temporal lobe in six (86%) and in the parietal-occipital area in one (14%). Ictal scalp EEG and MRI were congruent in five cases (71%), and incongruent in two (29%), who required intracranial EEG. Interictal EEG was often diffuse or multifocal. The index case had a neocortical left temporal DNET and contralateral seizure onset on scalp EEG. Five patients (71%) underwent a lesionectomy, but two (29%) required a lesionectomy plus corticectomy. At last follow-up, five patients (71%) were seizure free and two continued to have seizures but improved from baseline. Two patients (29%) were free of AEDs and five (71%) continued with medications., We confirm a complex pattern of epileptogenicity associated with DNET, often showing EEG discharges discordant with the lesion, and often requiring intracranial EEG investigations. The index case illustrates the difficulties in surgical decisions surrounding these patients. Nonetheless, surgical outcomes were favourable in most of our patients.,