Abstracts

RATIONALE: To report ten encountered patients with medically refractory epilepsy who had clinical and ictal evidence of medial temporal onset seizures in the presence of significant extratemporal MRI lesions.
METHODS: We retrospectively reviewed the charts of patients with extratemporal lesions who underwent presurgical evaluation of their seizures. We reviewed clinical data, ictal and interictal recordings, as well as the other ancillary testing prior to surgery.
RESULTS: Ten patients were identified, ages 30-50 (mean 42) with seizure durations 20- 40 years (mean 28.9 years). All had large extratemporal lesions on MRI, 7 had encephalomalacia (2 fronto-parietal-temporal, 2 frontal, 1 parietal, 2 parieto-occiptal), 1 had bilateral occipital heterotopias, 1 had a frontal hamartoma, and 1 had a parietal AVM. Five of these patients also had evidence of hippocampal atrophy on MRI. All patients had electrical evidence of temporal seizure onsets based on surface recordings (5 patients), and intracranial recordings (5 patients). Eight patients underwent temporal lobectomy, six of which became seizure free, whereas the remaining patients had significant improvement (Engel Class 2). Two of these patients had pathological findings of MTS, one of whom had evidence of hippocampal atrophy on MRI.
CONCLUSIONS: The finding of large extratemporal lesion in MRI may be misleading. Extratemporal lesions are not necessary epileptic in nature. Clinical semiology as well as ictal recordings may provide evidence of temporal onset seizures in some of these cases. Temporal lobectomy should be considered in patients with extratemporal lesions when the above criteria are met.