Abstracts

Rationale: Epilepsy surgery may cure seizures when a focal area of epileptogenesis is definable and resectable. Patients with multiple lesions are generally not considered surgical candidates as they frequently have multifocal epileptogenesis. We describe the detailed imaging and EEG characteristics of 4 cases with multiple lesions with only one epileptogenic lesion. Methods: Four pediatric patients with refractory epilepsy not associated with a tuberous sclerosis gene mutation who had multiple lesions and underwent comprehensive vEEG evaluation with surface EEG, invasive recordings, high resolution MRI and metabolic imaging with 18 FDG-PET are described. They all went for surgical resection and had complete seizure control at 6 months post operative.Results: Ages ranged from 21 months 5 years. All had refractory epilepsy with multiple daily seizures consisting of one seizure type. Lesions defined on MRI or by pathology included focal cortical dysplasias type 1, transmantle dysplasias type 2 with balloon cells, subependymal heterotopias, early strokes and vascular malformations. Two patients had two distinct lesions and 2 patients had 3 lesions. The surface interictal and ictal EEG localized to one lesion in 2 patients and a single stage resection was followed with good seizure outcome. In one patient marked 18 FDG-PET hypometabolism pointed to a lesion that did not demarcate well in the MRI. A subependymal heterotopia and cavernous angioma which proved not to be epileptogenic.Two patients underwent stereotactic depth evaluation targeting the lesions and perilesional tissue and epileptogenesis was found to be restricted to a single lesion which was then resected with good seizure control. Conclusions: Children with multiple lesions not associated with a TSC gene mutation may still be surgical candidates to treat refractory epilepsy if only one of the lesions is epileptogenic. Early referral and detailed presurgical evaluation with invasive EEG technology to localize seizure onset is helpful in these cases.