Abstracts

Rationale: Although mesial temporal sclerosis (MTS) is the most common lesion documented in adults with intractable temporal lobe epilepsy, it has not been well studied in children. Studies of pediatric temporal lobe epilepsy have shown that other etiologies, including tumors, focal cortical dysplasia (FCD), trauma or nonspecific gliosis, and vascular malformations may cause intractable temporal lobe epilepsy. However, it is often difficult to distinguish diverse pathologies using preoperative magnetic resonance imaging (MRI). In this study, we hypothesize that mesial temporal sclerosis is less common in pediatric temporal lobe epilepsy and that there is discordance between radiological and pathological diagnosis of MTS in this population. Methods: We retrospectively reviewed 27 intractable temporal lobe epilepsy pediatric patients who underwent surgical treatment at the University of Alberta Comprehensive Epilepsy Program. The pathology at surgery was reviewed and compared to preoperative magnetic resonance imaging as reported by Neuroradiologists. Results: All 27 patients had a preoperative radiological diagnosis of MTS. Following surgery the pathology studies revealed , 13/27 had pure MTS, while 14/27 had other diagnoses. Of the 14 patients with other diagnoses, four had dual pathology, both MTS and FCD, three had FCD, one had FCD and gliosis, three had low-grade tumors, one had a tuber of tuberous sclerosis, one had Rasmussen's encephalitis, and one patient had no specific pathology/normal. Conclusions: In this study, we found that despite a preoperative neuroimaging diagnosis of MTS, more than 50% of Pediatric patients with intractable temporal lobe epilepsy had other diagnoses, including dual pathology, tumor,, and FCD. We conclude that isolated mesial temporal sclerosis appears to be a less common etiology in pediatric temporal lobe epilepsy and is often difficult to distinguish with preoperative MRI.