Lesionectomy in epileptogenic gangliogliomas: seizure outcome and surgical results

We retrospectively analysed seizure outcome and surgical results in a series of 21 patients with ganglioglioma treated with lesionectomy. The 21 patients (13 males, eight females) had a history of epilepsy longer than 1 year and post-operative follow up of at least 1 year. Information on the duration of the seizures, type and frequency was retrieved from medical records. In all patients, surgery was limited to the tumour. The interval between onset of seizures and surgery ranged from 1 to 35 years (mean 11). Patient age ranged from 6 to 61 years (mean 27.5). Fifteen patients (71.4%) had complex partial seizures and six had simple partial seizures. Secondary generalisation was present in 10 patients (47.6%). Seizure frequency varied from several per day to one per month. Sixteen tumours were temporal (76.1%; 11 temporo-mesial, five temporo-lateral), and five were extratemporal (23.8%). The mean follow-up period was 5.4 years (range: 1.25-10 years). No tumour progression was observed. No patient died during surgery or the post-operative course. Fourteen patients (66.6%) were Engel class I (five temporo-mesial, five temporo-lateral, four extratemporal) and seven (33.3%) were Engel class II. Post-operative complications were observed in six patients (28.6%), two of whom had cerebellar haemorrhage, possibly due to increased transmural venous pressure. In our patients with temporal neocortical and extratemporal ganglioglioma, lesionectomy allowed good seizure control. The unsatisfactory outcome for mesiotemporal gangliogliomas might indicate the need for extensive neurophysiological presurgical evaluation in order to perform tailored surgery. To avoid cerebellar haemorrhage, attention should be paid to those factors involved in transmural venous pressure increases.