Abstracts

Rationale: Temporal lobe epilepsy is the most common type of focal onset epilepsy, typically associated with tumors, hemorrhage, trauma resulting in scarring, and mesial temporal sclerosis. Here we report a case series of intractable temporal lobe epilepsy secondary to a middle fossa encephalocele with the associated progression of electroencephalogram (EEG) and magnetic resonance imaging (MRI) findings.Methods: Two adult patients and one pediatric patient with intractable epilepsy were identified in a tertiary academic center over the past three years. All patients were found to have a left temporal lobe encephalocele with unremarkable physical examination findings. One patient suffered from head trauma as a child whereas no predisposing factor was identified in the other patient. Seizure frequency occurred weekly in the adults and monthly in the pediatric case despite appropriate antiepileptic medication dosage.Results: All patients underwent video EEG monitoring with surgical evaluation including MRI brain and single-photon emission computed tomography (SPECT). MRI brain identified a left temporal lobe enecphalocele whereas the EEG findings were suggestive of a more frontal predominance. These findings were attributed to the brain protrusion through the middle fossa resulting in a shifting dipole. Subsequently, all patients underwent transnasal encephalocele removal and nasal septum repair.Conclusions: Middle fossa encephalocele is a rare etiology for temporal lobe epilepsy and may be easily missed in milder cases. EEG can be confusing as in these particular cases due to protrusion of the brain from the confined space. Surgical repair is typically suggested in an attempt to improve seizure outcome. However, a larger study is needed to accurately evaluate the outcome of surgery.