Abstracts

RATIONALE: Dual pathology in temporal lobe epilepsy has been reported. Although extrahippocampal temporal brain lesions presenting with mesial temporal epilepsy are relatively common, brain lesions anatomically remote from the temporal lobe associated with mesial temporal epileptic foci are rare. The mechanism of secondary epileptogenesis in humans remains uncertain.
METHODS: Three patients, one with a parietal intraventricular meningioma and two with vascular malformations in the frontal and occipital regions associated with mesial temporal lobe epilepsy, are described. Patient 1. A 38-year-old woman developed simple partial seizures shortly after undergoing a right parietal craniotomy to excise an intraventricular meningioma; 10 years later, she developed complex partial seizures. Treatment with more than ten different anticonvulsants did not control these seizures. Nineteen years later, MRI of brain showed a small recurrent meningioma, right parietal encephalomalacia, and right hippocampal atrophy. EEG study with subdural electrodes recording revealed active epileptic discharges from the right parietal region and ictal discharges from the right mesial temporal region. Patient 2. A 30-year-old patient, who had a frontal arteriovenous malformation (AVM) with generalized seizures, presented with complex partial seizures within 1 year after undergoing an AVM excision; depth electrode recording disclosed an ipsilateral mesial temporal ictal discharges. This case was reported previously. Patient 3. A 41-year-old patient had occipital vascular malformations. Ictal epileptic discharges from the ipsilateral mesial temporal region were confirmed by EEG. All three patients underwent anterior temporal lobectomy and hippocampectomy. Patient 3 did not undergo excision of the occipital vascular lesion because of the risk of contralateral hemianopsia.
RESULTS: The Patient 1 became seizure free after the right anterior temporal lobectomy, right parietal cortical excision, and removal of the recurrent meningioma; pathology confirmed hippocampal sclerosis. Patient 2 had good improvement in seizure control after the right frontal AVM excision followed by the right anterior temporal lobectomy. Patient 3 remains seizure free after 10 years.
CONCLUSIONS: Potential relevance of kindling and secondary epileptogenesis was observed in these three patients. At the end of the presentation, the participants may discuss the mechanism of possible secondary epileptogenesis in human.