Abstracts

Dysembryoplastic neuroepithelial tumors (DNTs) are low grade glio-neuronal tumors that typically occur in superficial cortical locations where they are almost invariably associated with medically resistant epilepsy. In contrast, deeply situated DNTs are exceptionally rare, and their relationship to epilepsy remains controversial. To the best of our knowledge, there are no reported cases of intraventicular DNTs as a cause of epilepsy. We describe a middle aged man with a decade long history of medically intractable seizures which remitted after resection of a focal intraventricular DNT. We also review the literature on association of deeply situated DNTs with epilepsy.
Case report and review of literature.
A 47 year-old man presented with a 12-year history of episodic unpleasant sensations ascending from his feet to his pelvis, and sometimes to his chest, occurring in clusters every 2-6 weeks. Two years prior to presentation he developed weekly lapses in awareness. Neurological examination was normal. Seizures were refractory to carbamazepine, topiramate and lamotrigine, both in combination and as monotherapy. Interictal electroencephalogram (EEG) showed right anterior temporal (F8, T2[gt]T4) sharp waves. Ictal EEG during 4 complex partial seizures localized to the same region, and clinically involved left-hand automatisms followed by lip smacking. MRI showed a 1x2 cm lesion in the frontal horn of the right lateral ventricle that was hypointense on T1- and hyperintense on T2-weighted images and without enhancement; temporal lobe structures were normal. Intraoperative EEG monitoring with a depth electrode aimed at the ventricular lesion and cortical strips over the right frontal and superior temporal regions showed no definite spikes. Resection of the tumor led to resolution of patient[rsquo]s seizures, now with 10 months of follow up. Pathology revealed a glio-neuronal neoplasm with features of DNT.
Extracortical DNTs have been reported within the pons, midbrain tectum, thalamus, basal ganglia, cerebellum and the ventricles. Of these, only five cases presenting with epilepsy were confined entirely to the subcortical structures. These occurred most commonly in the caudate nucleus.
Intraventricular location of DNT is unusual and and to our knowledge has not been linked to medically intractable partial epilepsy. The present case illustrates this novel association and together with a handful of reports from the literature of epilepsy associated with DNTs in other extracortical locations, provides evidence for the intrinsic epileptogenicity of this tumor. This underscores the importance of considering glio-neuronal tumors in even atypical locations as a possible surgically amendable cause of intractable epilepsy.