Abstracts

Rationale: Low-grade cerebral neoplasms constitute a major pathologic substrate of children referred for epilepsy surgery. MRI scans reveal characteristic but rarely specific findings. Surgery in this setting offers excellent results in general, although some controversy over best surgical strategies for these patients still exists. Methods: Between 2000 and 2007, 40 pediatric patients with epilepsy and MRI diagnosis of suspected neuroglial tumors were surgically treated at our center. Patients underwent video-EEG, high-resolution MRI and neuropsychological assessments for preoperative evaluation and as part of a serial postsurgical follow-up. Results: Mean age at epilepsy onset was 7.2 years (SD 4.6), whereas mean delay from diagnosis to surgery was 3.0 years (SD 3.1). Medical intractability was not demonstrated in all patients. Most children had a focal epilepsy which correlated well with the location of the lesion, three patients had epileptic spasms and generalized epileptiform discharges, and eleven children had two or more epileptic foci. Tumor location was temporal in 21 patients (mesial temporal in 9) and extratemporal in 19 (6 frontal, 6 central, 2 parietal, 5 occipital/parieto-occipital). Mean age at surgery was 10.4 (SD 4.8). Lesionectomy was performed in 26 children, extended lesionectomy with cortical resection in eight and lobectomy in six. Histopathologic findings consisted of 18 dysembryoplastic neuroepithelial tumors, 15 gangliogliomas, and eight tumors of other type. Dual pathology was observed in eight cases: six had additional focal cortical dysplasia and two were associated with mesial temporal sclerosis. Mean postsurgical follow-up period was 4.52 years (SD 2,14). At last follow-up evaluation, 84.6% remained seizure-free, 7.7% had >90% seizure frequency reduction, and 7.7% experienced no worthwhile improvement. No statistically significant correlation was found between seizure-freedom and duration of epilepsy, type or location of tumor, type of surgical intervention, nor persistence of epileptiform EEG abnormalities. Further resection was performed in eight patients with residual or recurrent tumor, including one patient with anaplastic transformation of a ganglioglioma. Most patients experienced neuropsychological improvement one year after surgery. Two children with right temporal lobe tumors who underwent surgery before the age of three years showed neuropsychological deterioration in spite of good seizure outcomes. Conclusions: Pediatric patients with epilepsy and MRI findings suggestive of low-grade tumors must be promptly and thoroughly evaluated for early surgery. Serial postsurgical MRI follow-up is strongly recommended. This approach allows for an individualized surgical strategy, providing a great opportunity to attain a favourable seizure outcome and to achieve maximum cognitive potential, minimizing oncological morbidity.