Spontaneous Temporal Pole Encephalocele Presenting with Epilepsy: Report of Two Cases

doi:10.1016/j.wneu.2015.04.028

World Neurosurgery

Volume 84, Issue 3, September 2015, Pages 867.e1-867.e6

https://doi.org/10.1016/j.wneu.2015.04.028 Get rights and content

Background

Refractory temporal lobe epilepsy due to spontaneous temporal pole encephalocele is a rare but increasingly recognized condition. Optimal surgical management is complicated by the lack of knowledge regarding both the extent of the epileptogenic area and the need for repair of the encephalocele.

Case Description

We report two cases that add significant information to these issues. In Case 1, with a 5-year history of refractory seizures, implantation of diagnostic subdural electrodes into the anterior temporal base happened to abolish the seizures completely. No structural changes were evident on postoperative magnetic resonance imaging. In Case 2, with a large encephalocele and a 5-year history of refractory seizures, surgical disconnection of the temporal pole successfully abolished seizures without any need for encephalocele repair.

Conclusions

These two cases support the view that the epileptogenic area is confined to within the temporal pole for spontaneous temporal pole encephalocele. Temporopolar disconnection represents one surgical option for this entity that achieves seizure cessation without requiring extra repair procedures.

Introduction

Focal epilepsy associated with encephalocele is a rare but repeatedly reported condition 5, 16. Among encephaloceles in various regions, anterior temporal encephaloceles, or temporal pole encephaloceles, have attracted attention in association with refractory temporal lobe epilepsy (TLE) in recent years 1, 2, 3, 6, 7, 8. The actual incidence is not known and may be more frequent than previously thought because small encephaloceles in this region are easily overlooked on magnetic resonance imaging (MRI) 1, 3. Recognition of this lesion is of paramount importance for the management of TLE because the favorable seizure outcomes from surgical treatment of lesional TLE contrast sharply with the results of surgery for nonlesional TLE (19). Although all surgically treated cases in the literature became seizure free 1, 2, 3, 7, 9, 12, 14, 15, 16, 20, 21, 22, procedures varied widely among cases, including lesionectomy and anterior temporal lobectomy with and without hippocampectomy. This variety probably arises from the unknown extent of the epileptogenic area with this lesion. Moreover, measures of repair have not been fully documented and the optimal surgical strategy for this condition has yet to be determined. Herein, we report two cases of temporal pole encephalocele along with a review of the literature and propose a surgical option based on the clinical characteristics identified.

Section snippets

Case 1

A 21-year-old man without any specific medical history experienced his first seizure at 15 years old. Medical treatment with adequate doses of antiepileptic drugs (AEDs) including carbamazepine, phenytoin, zonisamide, and valproate failed to control seizures. He experienced five complex partial seizures (CPSs) and one secondarily generalized seizure per month on average by the time he was referred to us from an epileptologist seeking surgical treatment. No neurological deficits were identified

Discussion

Encephaloceles may arise congenitally or secondarily in various supratentorial regions of the skull. While all encephaloceles may present with epileptic seizures, middle fossa encephalocele and TLE appear to represent the most frequent combination (5). Middle fossa encephaloceles seem to include two distinct entities, of the anterior or posterior middle fossa. Posterior temporal encephalocele, or petrous encephalocele, is characterized by a mostly secondary nature, association with obesity and

Conclusions

Refractory TLE due to spontaneous temporal pole encephalocele is a rare but increasingly recognized condition. Optimal surgical management is complicated by unknown issues regarding the extent of the epileptogenic area and the necessity of repair of the encephalocele. We have reported two cases adding significant information for these issues. These two cases support the view that the epileptogenic area is confined to within the temporal pole for spontaneous temporal pole encephalocele. In

References (22)

R.W. Byrne et al.
Occult middle fossa encephaloceles in patients with temporal lobe epilepsy
World Neurosurg
(2010)
S. Gasparini et al.
Refractory epilepsy and encephalocele: lesionectomy or tailored surgery?
Seizure
(2014)
M. Giulioni et al.
Tailored surgery for drug-resistant epilepsy due to temporal pole encephalocele and microdysgenesis
Seizure
(2014)
H. Shimizu et al.
Hippocampal transection for treatment of left temporal lobe epilepsy with preservation of verbal memory
J Clin Neurosci
(2006)
J.F. Tellez-Zenteno et al.
Surgical outcomes in lesional and non-lesional epilepsy: a systematic review and meta-analysis
Epilepsy Res
(2010)
D.M. Whiting et al.
Intractable complex partial seizures associated with occult temporal lobe encephalocele and meningoangiomatosis: a case report
Surg Neurol
(1990)
A. Abou-Hamden et al.
Small temporal pole encephaloceles: a treatable cause of “lesion negative” temporal lobe epilepsy
Epilepsia
(2010)
K. Aquilina et al.
Microencephaloceles: another dual pathology of intractable temporal lobe epilepsy in childhood
J Neurosurg Pediatr
(2010)
M.L. Carlson et al.
Temporal bone encephalocele and cerebrospinal fluid fistula repair utilizing the middle cranial fossa or combined mastoid-middle cranial fossa approach
J Neurosurg
(2013)
H.J. Faulkner et al.
Epilepsy surgery for refractory epilepsy due to encephalocele: a case report and review of the literature
Epileptic Disord
(2010)

M. Giulioni et al.

Seizure outcome in surgically treated drug-resistant mesial temporal lobe epilepsy based on the recent histopathological classifications

J Neurosurg

(2013)

Cited by (15)

Encephalocele-Associated Drug-Resistant Epilepsy of Adult Onset: Diagnosis, Management, and Outcomes
2021, World Neurosurgery
Citation Excerpt :
The full spectrum of electroclinical expression has been associated with encephaloceles, from focal aware seizures, to focal impaired awareness seizures, to full generalized tonic-clonic seizures.13-16 Existing literature on encephaloceles in epilepsy mostly comprises case reports,12,15,17-19 small case series,20-23 and several retrospective studies.1,3-5,16,24-27 No prospective trials have been reported.
Epileptogenic encephaloceles, most frequently located in the temporal lobe, are a known lesional cause of focal epilepsy. Data are limited regarding diagnosis, management, and outcomes of patients with epilepsy in the setting of an encephalocele, because the literature mostly comprises case reports, case series, and retrospective studies. We conducted a broad literature review for articles related to encephaloceles and epilepsy regardless of level of evidence. Hence, this review provides a summary of all available literature related to the topic. Thirty-six scientific reports that fulfilled our inclusion criteria were reviewed. Most reported patients presented with focal impaired awareness seizures and/or generalized tonic-clonic seizures. Although most of the encephaloceles were located in the temporal lobe, we found 5 cases of extratemporal encephaloceles causing epilepsy. More patients who underwent either lesionectomy or lobectomy were seizure free at time of follow-up. In the temporal lobe, there is no clear consensus on the appropriate management for epileptic encephaloceles and further studies are warranted to understand the associated factors and long-term outcomes associated with epilepsy secondary to encephaloceles. Reported data suggest that these patients could be manageable with surgical procedures including lesionectomy or lobectomy. In addition, because of data suggesting similar results between procedures, a more conservative surgery with lesionectomy and defect repair rather than a lobectomy may have lower surgical risks and similar seizure freedom.
Unexpected pain with electrocortical stimulation in a teenager with temporal encephalocele
2021, Epilepsy and Behavior Reports
Temporal lobe encephalocele has emerged as a potentially unrecognized cause of drug-resistant temporal lobe epilepsy (TLE) that can be effectively treated with epilepsy surgery. Here we present a case in which a 17-year-old male with drug-resistant epilepsy and left temporal encephalocele underwent workup for epilepsy surgery, and experienced unexpected pain with electrocortical stimulation. Stimulation of stereo-EEG electrodes in the left temporal pole resulted in severe, unilateral left-sided facial pain due to inadvertent stimulation of the trigeminal nerve. Stereo-EEG showed seizure onset adjacent to encephalocele with no involvement of mesial temporal structures. A temporal pole resection sparing the mesial temporal structures and repair of the sphenoid bone defect was performed. The patient experienced post-operative seizure freedom, with no loss of language function or sensory deficits in the distribution of the trigeminal nerve. This case highlights temporal encephalocele as a potentially overlooked cause of TLE and underscores the anatomical proximity of the trigeminal nerve to the temporal pole, an important consideration for surgical planning.
Temporal lobe encephalocele, a subtle structural lesion that can be associated with temporal lobe epilepsy
2020, Neurologia
Characteristics of bilateral versus unilateral temporal encephalocele-associated epilepsy
2019, Seizure
To characterise bilateral temporal encephalocele (BTE)-associated epilepsy relative to unilateral temporal encephalocele (UTE)-associated epilepsy as a rare but curable cause of structural epilepsy using demographics, epilepsy status and imaging findings.
In this single-centre retrospective study we included all patients from June 2015 to August 2018, who suffered from epilepsy and were diagnosed with a temporal encephalocele. Data were systematically collected and analysed for differences between BTE and UTE.
Seventeen epilepsy patients diagnosed with temporal encephaloceles (TE) were identified. One-third exhibited BTE. The age of epilepsy onset was higher in patients with BTE compared to UTE (median 51 vs. 37 years, p = 0.074). Latency between epilepsy diagnosis and definitive TE diagnosis differed considerably with a median five-fold shorter duration for the BTE-group when compared to the UTE-group (2–10 years, p = 0.02). Five of seven (81%) patients with BTE were pharmacoresistant, while this applied to only five out of ten (50%) patients with a UTE.
When compared to UTE-associated epilepsy, BTE-associated epilepsy is characterised by a later age at onset, shorter delay in TE diagnosis and more frequent drug-resistance. As epilepsy surgery is a valid treatment option for both syndromes, a standardised diagnostic workup should be implemented for temporal lobe epilepsy (TLE) patients with unknown aetiology to facilitate early detection of UTE and BTE.
Temporal encephaloceles and coexisting epileptogenic lesions
2023, Epilepsia Open
Temporal encephalocele: a rare but treatable cause of temporal lobe epilepsy
2022, Epileptic Disorders

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: Conflict of interest statement: The author declares that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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Case ReportSpontaneous Temporal Pole Encephalocele Presenting with Epilepsy: Report of Two Cases

Background

Case Description

Conclusions

Introduction

Section snippets

Case 1

Discussion

Conclusions

World Neurosurg

Seizure

Seizure

J Clin Neurosci

Epilepsy Res

Surg Neurol

Small temporal pole encephaloceles: a treatable cause of “lesion negative” temporal lobe epilepsy

Epilepsia

Microencephaloceles: another dual pathology of intractable temporal lobe epilepsy in childhood

J Neurosurg Pediatr

Temporal bone encephalocele and cerebrospinal fluid fistula repair utilizing the middle cranial fossa or combined mastoid-middle cranial fossa approach

J Neurosurg

Epilepsy surgery for refractory epilepsy due to encephalocele: a case report and review of the literature

Epileptic Disord

Seizure outcome in surgically treated drug-resistant mesial temporal lobe epilepsy based on the recent histopathological classifications

J Neurosurg

Case Report
Spontaneous Temporal Pole Encephalocele Presenting with Epilepsy: Report of Two Cases