Temporal encephaloceles in epilepsy patients and asymptomatic cases: Size may indicate epileptogenicity

Epilepsia. 2021 Jun;62(6):1354-1361. doi: 10.1111/epi.16900. Epub 2021 May 3.


Objective: This study was undertaken to identify temporal encephaloceles (TEs) and examine their characteristics in patients with temporal lobe epilepsy (TLE) and extratemporal lobe epilepsy (ETLE), as well as in asymptomatic cases.

Methods: Four hundred fifty-eight magnetic resonance imaging scans were examined retrospectively to identify TE in 157 patients with TLE, 150 patients with ETLE, and 151 healthy controls (HCs).

Results: At least one TE was identified in 9.6% of the TLE patients (n = 15, 95% confidence interval [CI] = 5.3%-15.3%), in 3.3% of patients with ETLE (n = 5, 95% CI = 1.1%-7.6%), and in 2.0% of the HCs (n = 3, 95% CI = .4%-5.7%), indicating a significantly higher frequency in patients with TLE compared to ETLE and HC subjects (p = .027, p = .005). Examining the characteristics of TEs in both asymptomatic and epilepsy patients, we found that TEs with a diameter of less than 6.25 mm were more likely to be asymptomatic, with a sensitivity of 91.7% and a specificity of 73.3% (area under the curve = .867, 95% CI = .723-1.00, p = .001).

Significance: Temporal encephaloceles may occur without presenting any clinical symptoms. Patients with TLE show a higher frequency of TEs compared to the ETLE and HC groups. According to our study, TE size could be used to suggest potential epileptogenicity.

Keywords: MRI-negative epilepsy; asymptomatic temporal encephaloceles; epilepsy surgery; temporal encephaloceles; temporal lobe epilepsy.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Electroencephalography
  • Encephalocele / diagnostic imaging
  • Encephalocele / etiology*
  • Epilepsy / complications*
  • Epilepsy / diagnostic imaging*
  • Epilepsy, Temporal Lobe / complications*
  • Epilepsy, Temporal Lobe / diagnostic imaging*
  • Female
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Retrospective Studies
  • Temporal Lobe / diagnostic imaging*
  • Young Adult