Abstracts

Low grade tumors, especially of neuronal lineage are commonly associated with epilepsy. Refractory epilepsy in these cases is usually amenable to surgical treatment, often with good results. We studied a series of cases to analyze possible factors associated with good surgical outcome in patients with low grade temporal tumors. Retrospective analysis of clinical, ictal and interictal EEG, neuroimaging and pathology data in a series of consecutive patients who underwent temporal resection for medically refractory epilepsy secondary to temporal lobe low grade tumors. Twenty eight patients (17 men, ages ranging from 2-51 years) with low grade temporal lobe tumors were operated between and 1993 and 2004. Sixteen patients had more than 20 seizures/month at the time of surgery. Gangliogliomas were the most common pathologic diagnosis, accounting for 50% of the cases. 22 patients underwent lesionectomy with amygdalo-hippocampectomy and 6 lesionectomy (partial in one). Mean follow-up period was 57,4 months (range 2-129 months). Surgical outcome was excellent (Engel 1) in 20/28 (71%) cases. There was no correlation between surgical outcome and age at epilepsy onset, frequency of seizures at the time of the surgery, lesion side, bilateral or unilateral ictal and interictal EEG activity, or ictal activity not congruent with the lesion. Patients with abnormal neurological exam (Engel 1: 2/7 or 28%), astrocytic tumors (Engel 1: 4/7 or 57%) or extratemporal interictal EEG activity (Engel 1 1/3 or 33%) had slightly poorer surgical outcome than those with normal neurological exam (18/21 or 85%, p= 0,17), or neuronal lineage tumors (15/21 or 71%) or interictal EEG activity restricted to the temporal lobe (19/25 or 76%). In this series, bitemporal ictal or interictal EEG abnormalities or ictal EEG activity not concordant with the lesion did not determine a poor surgical outcome. Factors such as abnormal neurologic exam and presence of extratemporal epileptiform discharges on interictal EEG as predictors of poorer surgical outcome should be evaluated in larger series.