Abstracts

Rationale: 18 to 19% of the slow-growing, usually low-grade, primary brain tumors present initially with epilepsy. In the setting of chronic epilepsy, tumors constitute 25-30% of the cases. Methods: Retrospective, descriptive study of all patients presenting with refractory epilepsy due to tumors and operated in the scope of the Epilepsy Surgery Group of the CHLN- Hospital de Santa Maria, in Lisbon. The following variables were retrieved from the files of the Laboratory of Neuropathology of our institution, clinical and surgery charters, and phone contact with patients/relatives or clinicians: age, gender, elapsed time since the onset of epilepsy until surgery, tumor topography, and extension of surgical resection. Seizures outcome was assessed using Engel s classification at last follow-up. Results: 22 cases, 15 males, median age of epilepsy onset of 21 years (range 7 to 50), and median age at the time of surgery of 37 years (range 8 to 57). 17 (77.2%), 4 and 1 tumor arised from the temporal, frontal and parietal lobes, respectively. 17 (77.2%) tumors were totally removed. 7 tumors were gangliogliomas (grade I), 5 were DNTs (grade I), 5 were astrocytomas (4 grade I and 1 grade II), 4 were oligodendrogliomas (grade II) and 1 was a non-specified glioneuronal tumor (grade I). Median time of follow-up after surgery was 60 months (3-148). Overall, 77% of the patients were free of disabling seizures (Engel class I). 14 (82.4%) of the patients with grade I tumors were in Engel class I whereas 3 (60%) of those with grade II tumors were in the same class. From the group of grade I (13 pts), 11 (84.6%) patients with total resections were in Engel class I whereas 1 (75%) of the subtotal group where in the same class. There were 3 cases of complications, 1 transient and 2 permanent (foot paresis and psychosis). Conclusions: Overall, patients with refractory epilepsies due to tumors which are operated in the scope of an epilepsy surgery program, experience a good postsurgery epilepsy outcome. The extension of resection and the grade of anaplasia may play a role in this outcome.