Surgical Strategy and Outcomes for Epileptic Patients with Focal Cortical Dysplasia or Dysembryoplastic Neuroepithelial Tumor

Abstract

Summary: Purpose: The purpose of this study was to clarify and compare the influence of surgical strategy on relief from seizures in patients with focal cortical dysplasia (FCD) and those with dysembryoplastic neuroepithelial tumor (DNT). Methods: Six patients with FCD and five patients with DNT, all of whom underwent surgical resection for medically intractable epilepsy, were compared in terms of presurgical seizure types and frequency, location of lesions, magnetic resonance imaging (MRI), single‐photon emission computed tomography (SPECT) with 99mTc‐ECD, scalp electroencephalogram (EEG), and long‐term video‐EEG recording. Prolonged subdural recordings and intraoperative electrocorticograms (ECoG) were analyzed. The influences of surgical strategies on seizure outcomes were retrospectively analyzed. Results: In all the FCD patients, ictal SPECT revealed hyperperfusion in the regions where MRI showed FCD. Interictal epileptiform activity and ictal seizure onset on ECoG performed with subdural electrodes were localized on the FCD itself. In contrast, the tumors of all the DNT patients were depicted as hypoperfuse areas on interictal SPECT scans. Ictal SPECT in one DNT patient showed hyperperfusion in the area enclosing the tumor. Interictal spiking in all DNT patients and ictal seizure onset in two DNT patients were not in the lesions themselves but in an area enclosing the lesion. All but one patient with FCD who underwent total lesionectomy became seizure free. All DNT patients who underwent resection of the epileptogenic cortex associated with lesionectomy became seizure free or achieved a 90% reduction in seizures. Conclusions: FCD has intrinsic epileptogenicity, whereas DNT is encompassed by epileptogenic cortical areas. Therefore, total lesionectomy is an essential strategy for FCD, whereas resection of the epileptic focus associated with lesionectomy of a DNT lesion is necessary to control seizures.

Ictal Perfusion Patterns Associated with Single MRI‐Visible Focal Dysplastic Lesions: Implications for the Noninvasive Delineation of the Epileptogenic Zone

“…Patterns 1–3 were found in all patients injected during a partial seizure. Characteristic for these was hyperperfusion within and immediately surrounding the MRI‐visible FDL, consistent with intrinsic epileptogenicity of FDL (5,18) and confirming previous reports (11,19–21). These patterns followed a gradient of hyperperfusion in which the region with the maximum z score was either (i) at the lesion or its immediate surroundings (pattern 1), (ii) about 2 cm away from the lesion but connected to a second lobe of the hyperperfusion cluster at the lesion or its immediate surroundings through a propagation trail (pattern 2), or (iii) about 5 cm away from the lesion but connected to another hyperperfusion cluster at the lesion or its immediate surroundings through a propagation trail (pattern 3).…”

Differential Cellular Gene Expression in Ganglioglioma

“…Because of their propensity for causing seizures despite optimal antiepileptic drug therapy, GG often require resection to achieve seizure control. Early resection reduces long‐term morbidity and mortality from seizures, making surgery the treatment of choice for most patients when compared to medical management (Silver et al, 1991; Kirkpatrick et al, 1993; Packer et al, 1994; Johnson et al, 1997; Morris et al, 1998; Jorge et al, 2000; Aronica et al, 2001a; Ildan et al, 2001; Kameyama et al, 2001; De Munnynck et al, 2002; Pasquier et al, 2002). A second concern for a small minority of patients with GGs, is that underlying the benign nature of these tumors lurks the potential for malignant transformation (Hayashi et al, 2001; De Munnynck et al, 2002; Whittle et al, 2002) especially within the glial component (Jay and Becker, 1994; David et al, 2000).…”

Electrocorticographic Discharge Patterns in Glioneuronal Tumors and Focal Cortical Dysplasia

“…Palmini et al reported that ictal or continuous epileptiform discharges (consisting of recruiting/derecruiting patterns, repetitive bursting patterns and (quasi)continuous rhythmic spiking) were related to cortical dysplasia (18). Since then, various reports on ECoG findings in cortical dysplasia have been published using different nomenclature and definitions, such as, slow repetitive spikes (37), rhythmic spike discharges (38), seizure patterns (consisting of continuous spiking, bursts of rhythmic spikes and trains of fast activity) (19), continuous epileptogenic discharges (25), frequent or continuous rhythmic spiking (39), and continuous frequent spiking (22). This difference in terminology makes direct comparison of these studies difficult.…”

“…Several reports have described the clinical, neuroimaging, and histological characteristics of these indolent GNTs (21), but few(11,20,23,24,26,40–48) investigators have studied the ECoG spike discharge patterns of patients with a GNT, in contrast to those with FCD. Only a few studies report EEG and ECoG findings separately, and when they have, emphasis was mainly on the topography and distribution of the (inter) ictal discharge, and not on spike discharge patterns (11,25,26,40,48). For example, Raymond et al found that unequivocal spiking or sharp waves on the interictal scalp EEG were present in most patients with DNT but were concordant with the visible lesion in only three patients (40).…”

“…The technique is based on the assumption that epileptiform discharges recorded from the cortex are indicators of local cortical involvement in an epileptogenic network and are also related to interictal spikes recorded during presurgical surface EEGs. While there are several reports on ECoG spike discharge patterns in FCD, with persistence of seizure patterns or ictal‐like and/or continuous epileptiform discharges in postresection ECoG recordings being predictive of poor surgical outcome (18,19), less is known about the ECoG spike discharge patterns in patients with GNT, often because only small patient samples have been investigated (20–26). Because of the common neurodevelopmental origin and features (cortical dysplasia) of GNT and FCD, patients with these disorders may have similar electrocortocographic abnormalities, abnormalities which may determine the extent of the resection and surgical outcome.…”