Epileptogenic role of occult temporal encephalomeningocele

Objective The purpose of this case-control study is to evaluate the prevalence of occult temporal encephalomeningocele (OTE) in patients with temporal lobe epilepsy (TLE) of unknown etiology presenting to an epilepsy center, independently from drug sensitivity. Methods We studied 95 patients with TLE (51 female, mean age 49.4 ± 17.1 years) and 151 controls (88 female, mean age 54.1 ± 21.0 years) using a 1.5T brain MRI, including balanced steady-state gradient echo sequences, targeted to the temporal lobes. Results OTE was found in 5.2% of the TLE population (9.5% of drug-resistant TLE) and in none of the controls (p = 0.008). Two patients with OTE and drug-resistant TLE became seizure-free after lesionectomy (follow-up 18–24 months). Conclusion OTE is not a rare finding in unselected patients with TLE of unknown origin, provided that it is carefully searched. The absence of OTE in a large group of nonepileptic controls adds evidence to its epileptogenic role.