Surgical outcomes and seizure control rates after resection of dysembryoplastic neuroepithelial tumors

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>In this study the authors review the outcomes in pediatric patients who presented with seizures and underwent resection of dysembryoplastic neuroepithelial tumors (DNETs). The authors focus on the diagnostic evaluation and surgical techniques that facilitate gross–total tumor resection and subsequent freedom from seizures.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>Eighteen patients between the ages of 1 month and 13 years who presented with seizures underwent resection of DNETs between January 1992 and December 2004. Preoperative evaluation included magnetic resonance (MR) imaging and interictal scalp electroencephalography (EEG) in all patients, functional MR imaging in eight patients, video monitoring with ictal scalp EEG in 12 patients, interictal single-photon emission computerized tomography (SPECT) scanning in one patient, and ictal SPECT scanning in two patients. Thirteen patients underwent one-stage procedures, whereas five underwent two-stage procedures (implantation of monitoring electrodes followed by tumor resection), either for functional language mapping (three patients) or due to inconclusive preoperative data (two patients). Intraoperative electrocorticography (ECoG) was performed in 17 patients and led to resection of the cerebral cortex beyond the tumor margins in 10 of them. According to operative reports, gross–total tumor resections were achieved in all patients, but one child had minimal residual tumor on postoperative MR images that has remained stable. The only surgical complication was a transient third cranial nerve palsy. Over a median follow-up duration of 1.6 years, all patients are seizure free and without radiographically detected tumor recurrence.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Dysembryoplastic neuroepithelial tumors are a highly treatable cause of epilepsy in children. Excellent rates of complete tumor resection and seizure control with minimal morbidity can be attained using intraoperative ECoG and two-stage surgical procedures when appropriate.</jats:p></jats:sec>

Seizures in Children with Brain Tumours — Epidemiology, Significance, Management, and Outcomes

“…Overall, as of the paper's publication, only eight of the twenty patients had survived beyond infancy, with five now into adulthood (ages 18 -26) [170]; two of the adult survivors were severely disabled at the time of the report, both having a Karnofsky score [224] of just 40%. Also worth noting from Table 2 are the six studies in which only patients with dysembryoplastic neuroepithelial tumours (DNETs) were included (Table 3) [61,62,94,132,182,184]. These six studies encompass 132 patients, of mean age 9.7 years, amongst whom total tumour resection was achieved in almost 82%, seizure freedom in 87%, and seizure improvement in all but a single patient (99%).…”

“…Though one study [86] included six paediatric patients with high-grade gliomas (either GBM or grade III astrocytoma), and another indicated 11 patients with either grade III or grade IV lesions [35], almost all of the remaining 724 patients had low-grade (grade I or II) lesions, including various low-grade gliomas and glioneuronal tumours, and less typically epileptogenic tumours like craniopharyngiomas and a dysplastic cyst. Spanning these studies, surgical approaches clearly differed, with some surgeons either largely or exclusively performing lesionectomies alone, others performing further procedures like partial lobectomies [86,148] and amygdylohypocampectomies [182], and still others using various intra-operative mapping technologies like electrocortography (ECoG) [63,132,184,214] to identify and ultimately resect extra-tumoral epileptogenic tissue. However, the ubiquitous goal was total tumour resection, whenever possible, an objective that was achieved in roughly two-thirds of cases.…”

“…The major concern with the latter two scenarios is that tumour resection either was incomplete, or that extra-tumoral epileptogenic tissue was not removed. Over the years, attempts have been made to optimize the resection of epileptogenic lesions by both better delineating their margins and identifying extra-tumoral epileptogenic tissue, using intra-operative tools like electrocorticography (ECoG) to identify potential seizure-inducing tissue irregularities like cortical dysplasia [63,77,93,132,1 [6] 3 , 184,214,216,240,241]. This has led to debate regarding the relative benefits and safety of performing epilepsy surgery rather than just lesionectomies in patients with tumour-triggered seizures [242]; though, in fact, many surgeons have been utilizing additional surgical steps like lobectomies, amygdylohypocampectomies and, in extreme cases, hemispherectomies for decades [63,86,94,117,132,148,149,168,182,185,214,217,218,222,227,243].…”

“…A wide range of opinions and practices exist regarding how aggressive to pursue diagnostic imaging in children presenting with seizures [36,41,51,79,80,100,[127][128][129][130][131][132][133]. For example, in one series of eighteen patients between the ages of 1 month and 13 years who presented with seizures and were discovered to have DNETs between January 1992 and December 2004, the preoperative evaluation included magnetic resonance (MR) imaging and interictal scalp electro-encephalography (EEG) in all patients, but functional MR imaging also was performed in eight patients, video monitoring with scalp EEG during seizures in 12 patients, interictal single-photon emission computerized tomography (SPECT) scanning in one patient, and ictal SPECT scanning in two patients [132]. Meanwhile, in their 2010 review of eleven clinical trials for anti-epileptic drugs (AEDs) conducted over the preceding two years, Jansky et al noted that none of the trials required MRI as part of the patient enrollment protocol [128].…”

A Patient with a Dysembryoplastic Neuroepithelial Tumor Who Underwent Epilepsy Surgery after Initial Seizure

“…Since DNTs are benign tumors, the aim of surgery is to treat the associated intractable epilepsy, and it is well known that the surgical strategy is resection of the associated epileptogenic zone and the tumor, which are identified by chronic and/or intraoperative electrocorticography (ECoG) [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16]. However, the surgical strategy in DNT with a single seizure or well-controlled seizures has not been fully discussed.…”