Abstracts

Rationale: Intractable epilepsy with encephalocele is uncommon but well reported. Surgical approach varies depending on type of seizures, type of encephalocele (congenital vs aquired), location (temporal vs extratemporal), MRI changes (with associated signal abnormality vs none), and the concordance of studies (scalp EEG, brain MRI, PET scan and neuropsychological testing).Methods: We are reporting the surgical approach and result of 1/3 cases of encephalocele and related epilepsy. CASE 1: 24 yo ambidextrous man with seizures since 22 y.o . Semiology: ictal expressive aphasia, right forced head and eyes version and lip-smacking. Video-EEG in 2014: 5 complex partial seizures with broad onset in the left fronto-temporal channels, favoring neocortical onset pattern. MRI in 2014: Multiloculated, nonenhancing, expansile cystic lesion involving the left skull base, intracranial extension into the left middle cranial fossa and communication with the left sylvian fissure. Seizure frequency: monthly on Levetiracetam and Lacosamide. CASE 2: 28 yo RHM with seizures since the age of 25 y.o. Well controlled on Levetiracetam with no seizure since June of 2014. Initial Head CT reported left frontal lytic lesion. MRI showed small encephalocele in left frontal supraorbital margins. EEG by report from 2012 was normal. CASE 3: 68 yo RHM with focal seizures since 43 years of age. Semiology: lip-smacking, excessive drooling, right arm rolling movements, confusion and occasoinal secondary generalization. Video EEG in 2012: 2 seizures from right temporal onset. MRI in 2009 and 2013: reported as normal with no hippocampal asymmetry. Further review showed stable right anterior temporal pole small encephalocele. Seizure frequency is once every 2-3 months. Patient is maintained on Lamotrigine, Pregabalin and Clonazepam. Previouse AEDs: LEV, TPM, VPA, OXC, CBZ, Gabatril, GBP. Declined epilepsy surgery.Results: CASE 1: Encephalocele type: congenital Location: left temporal Size: Large Seizure type: Complex partial without secondary MRI: Large anterior temporal skull base meningioencephalocele with increased T2 signal in the adjacent cortical tissues. No signal abnormality in the L hippocampus itself Functional MRI: left language dominance. No PET or neuropsychological testing. Patient underwent encephalocele repair with marginal anterior temporal resection on 7/25/2014. He is still seizure free while on medications (lower dose of LEV). Pathology: Focal neuronal heterotopia within white matter with no evidence of gliosis or inflammation.Conclusions: Epilepsy surgery approach and technique for medically intractable seizures in patients with encephalocele vary. The main questions are: Is invasive EEG monitoring needed? and Is minimal cortical resection sufficient for seizure freedom? We are reporting a case of very large left temporal meningioencephalocele with seizure freedom despite limited resection and no need for intracranial EEG monitoring. Meningioencephalocele might be associated with microscopic congenital malformation like heterotopic neurons as seen in our case. Our case favors limited resection and repair of encehalocele rather than invasive monitoring and larg lobectomy.