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Objective: Assessing the diagnostic significance of MR morphometry in determining the localization of focal cortical dysplasias (FCD)., Material and Methods: The study included 13 children after surgery for drug-resistant epilepsy caused by FCD type II and stable postoperative remission of seizures (Engel class IA, median follow-up 56 months). We analyzed the results of independent expert assessment of native MR data by three radiologists (HARNESS protocol) and MR morphometry data regarding accuracy of FCD localization. We considered 2 indicators, i.e. local cortical thickening and gray-white matter blurring., Results: FCD detection rate was higher after MR morphometry compared to visual analysis of native MR data using the HARNESS protocol. MR morphometry also makes it possible to more often identify gray-white matter blurring as a sign often missed by radiologists ( p <0.05)., Conclusion: MR morphometry is an additional non-invasive method for assessing the localization of FCD.

Objective: The authors perform thorough, noninvasive presurgical evaluations for intractable epilepsy at their center and avoid unnecessary intracranial EEG when possible. The purpose of this study was to clarify the appropriateness of their lesion-oriented surgical strategy for localized focal cortical dysplasia (FCD) type II., Methods: Fifty-one patients with pathologically proven localized FCD type II who were followed for at least 1 year after surgery were included. Patients with FCD type II with lobar or multilobar distribution were excluded. The results of presurgical evaluations, including thin-slice 3-T MRI, FDG-PET, and ictal SPECT, as well as surgical procedures and postoperative seizure and functional outcomes, were examined retrospectively., Results: MRI was positive in 46 (90%) of 51 patients, and FDG-PET revealed localized hypo- or hypermetabolism in 47 (92%) of 51 patients. Ictal SPECT revealed concordant hyperperfusion in 37 of 42 patients examined. Intracranial EEG was used in only 13 patients (25%), including 5 with negative MRI results and 4 with subtle MRI findings. Of the 15 patients with FCD in the vicinity of eloquent (sensorimotor and language) areas, intracranial EEG was used in 4. Lesionectomy was performed in all 51 patients. Intraoperative electrocorticography (ECoG) was performed in 8 patients, but the findings were not used to tailor the extent of resection. Postoperative seizure outcomes were Engel class I in 47 patients (92%) and Ia in 45 (88%). In the 15 patients with FCD in the vicinity of eloquent areas, 13 (87%) achieved a class I outcome. Predictive factors for favorable seizure outcome were complete resection of the MRI lesion (p = 0.006) and frontal lobe surgery (p = 0.012). Postoperative neurological deficits were noted in only 4 (27%) of 15 patients with FCD in the vicinity of eloquent areas. All 5 MRI-negative patients achieved an Engel class I outcome., Conclusions: In most of the patients with localized FCD type II, MRI and/or FDG-PET detected the localized abnormality. Lesionectomy without intracranial EEG led to seizure freedom in most cases. Even when lesions were in the vicinity of eloquent areas, seizure and functional outcomes were favorable. Intraoperative ECoG may thus be unnecessary. Complete resection of the lesion is essential for favorable seizure outcome in MRI-positive patients. In MRI-negative patients, surgery with intracranial EEG guided by FDG-PET provided seizure-free outcomes.

We report a 15-year-old male patient with recurrent epileptic seizures for 12 years. Oral multiple drugs do not work well to his condition. MRI FLAIR scans revealed focal cortical dysplasia type II in the right parietal lobe. The diagnosis of the patient was drug-refractory epilepsy, FCD-related secondary epilepsy. According to the shape of the FCD lesion, electrodes were implanted in a tapered pattern along the bottom of the sulcus to completely destroy the focus. Magnetic resonance imaging at 6 months after surgery revealed that the FCD at the sulcus bottom was completely destroyed. After 26 months of follow-up, the patient had undergone no epileptic seizures, reaching Engel class I. For FCD that are located deep in the brain and adjacent to functional areas, craniotomy has a high risk. And stereoelectroencephalography-guided radiofrequency thermocoagulation may be a preferred treatment., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Objective: Focal cortical dysplasia (FCD) is a common cause of early-onset intractable epilepsy, and resection is a highly sufficient treatment option. In this study, the authors aimed to provide a retrospective analysis of pre- and postoperative factors and their impact on postoperative long-term seizure outcome., Methods: The postoperative seizure outcomes of 50 patients with a mean age of 8 ± 4.49 years and histologically proven FCD type II were retrospectively analyzed. Furthermore, pre- and postoperative predictors of long-term seizure freedom were assessed. The seizure outcome was evaluated based on the International League Against Epilepsy (ILAE) classification., Results: Complete resection of FCD according to MRI criteria was achieved in 74% (n = 37) of patients. ILAE class 1 at the last follow-up was achieved in 76% (n = 38) of patients. A reduction of antiepileptic drugs (AEDs) to monotherapy or complete withdrawal was achieved in 60% (n = 30) of patients. Twelve patients (24%) had a late seizure recurrence, 50% (n = 6) of which occurred after reduction of AEDs. A lower number of AEDs prior to surgery significantly predicted a favorable seizure outcome (p = 0.013, HR 7.63). Furthermore, younger age at the time of surgery, shorter duration of epilepsy prior to surgery, and complete resection were positive predictors for long-term seizure freedom., Conclusions: The duration of epilepsy, completeness of resection, number of AEDs prior to surgery, and younger age at the time of surgery served as predictors of postoperative long-term seizure outcome, and, as such, may improve clinical practice when selecting and counseling appropriate candidates for resective epilepsy surgery. The study results also underscored that epilepsy surgery should be considered early in the disease course of pediatric patients with FCD type II.

Objective: To determine whether 1-stage, limited corticectomy controls seizures in patients with MRI-positive, bottom-of-sulcus dysplasia (BOSD)., Methods: We reviewed clinical, neuroimaging, electrocorticography (ECoG), operative, and histopathology findings in consecutively operated patients with drug-resistant focal epilepsy and MRI-positive BOSD, all of whom underwent corticectomy guided by MRI and ECoG., Results: Thirty-eight patients with a median age at surgery of 10.2 (interquartile range [IQR] 6.0-14.1) years were included. BOSDs involved eloquent cortex in 15 patients. Eighty-seven percent of patients had rhythmic spiking on preresection ECoG. Rhythmic spiking was present in 22 of 24 patients studied with combined depth and surface electrodes, being limited to the dysplastic sulcus in 7 and involving the dysplastic sulcus and gyral crown in 15. Sixty-eight percent of resections were limited to the dysplastic sulcus, leaving the gyral crown. Histopathology was focal cortical dysplasia (FCD) type IIb in 29 patients and FCDIIa in 9. Dysmorphic neurons were present in the bottom of the sulcus but not the top or the gyral crown in 17 of 22 patients. Six (16%) patients required reoperation for postoperative seizures and residual dysplasia; reoperation was not correlated with ECoG, neuroimaging, or histologic abnormalities in the gyral crown. At a median 6.3 (IQR 4.8-9.9) years of follow-up, 33 (87%) patients are seizure-free, 31 off antiseizure medication., Conclusion: BOSD can be safely and effectively resected with MRI and ECoG guidance, corticectomy potentially being limited to the dysplastic sulcus, without need for intracranial EEG monitoring and functional mapping., Classification of Evidence: This study provides Class IV evidence that 1-stage, limited corticectomy for BOSD is safe and effective for control of seizures., (© 2021 American Academy of Neurology.)

Background: Awake craniotomy (AC) and direct electric stimulation emerged together with epilepsy surgery >80 years ago. The goal of our study was to evaluate the benefits of awake surgery in patients with drug-resistant epilepsy caused by focal cortical dysplasia (FCD) affecting eloquent areas., Methods: Our material included 95 patients with drug-resistant epilepsy and FCD, who were operated on between January 2009 and December 2018. These 95 patients were assigned into 3 groups: AC; general anesthesia (GA) with intraoperative neuromonitoring; and GA without intraoperative neuromonitoring. We investigated the following variables: age at surgery, lesion side, eloquent cortex involvement, brain mapping success rate, epilepsy surgery success rate, intraoperative complications, postoperative complications, and intraoperative changes of the preoperative resection plan according to results of the brain mapping by direct electric stimulation., Results: We found statistically significant differences between the AC and GA groups in the mean age at operation, lesion side, eloquent localization, and postoperative transient neurologic deficit. Seizure outcome in the AC was satisfactory (71% complete seizure control) and comparable to the seizure outcome in the GA groups. Our preoperative plan was changed because of functional constraints in 6 patients (43%) operated on during AC., Conclusions: AC during epilepsy surgery for FCD in eloquent areas may change the preoperative plan. The good rate of postoperative seizure control and the absence of permanent postoperative neurologic deficit in our series is the main proof that AC is a useful tool in patients with FCD involving the eloquent cortex., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: Reliable localization of the epileptogenic zone is necessary for successful epilepsy surgery. Neurophysiological biomarkers include ictal onsets and interictal spikes. Furthermore, the epileptic network shows oscillations with potential localization value and pathomechanistic implications. The cellular origin of such markers in invasive EEG in vivo remains to be clarified., Methods: In the presented pilot study, surgical brain samples and invasive EEG recordings of seven patients with surgically treated Focal Cortical Dysplasia (FCD) type II were coregistered using a novel protocol. Dysmorphic neurons and balloon cells were immunohistochemically quantified. Evaluated markers included seizure onset, spikes, and oscillatory activity in delta, theta, gamma and ripple frequency bands, as well as sample entropy and phase-amplitude coupling between delta, theta, alpha and beta phase and gamma amplitude., Results: Correlations between histopathology and neurophysiology provided evidence for a contribution of dysmorphic neurons to interictal spikes, fast gamma activity and ripples. Furthermore, seizure onset and phase-amplitude coupling in areas with dysmorphic neurons suggests preserved connectivity is related to seizure initiation. Balloon cells showed no association., Conclusions: Phase-amplitude coupling, spikes, fast gamma and ripples are related to the density of dysmorphic neurons and localize the seizure onset zone., Significance: The results of our pilot study provide a new powerful tool to address the cellular source of abnormal neurophysiology signals to leverage current and novel biomarkers for the localization of epileptic activity in the human brain., Competing Interests: Disclosure of Conflicts of Interest None of the authors has any conflict of interest to disclose., (Copyright © 2021 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Introduction: Focal Cortical Dysplasia (FCD) represents a broad spectrum of histopathological entities that cause drug-resistant epilepsy. Surgery has been shown to be the treatment of choice, but incomplete resection represents the leading cause of seizure persistence. Preliminary experiences with intraoperative ultrasound (ioUS) have proven its potential in defining and characterizing the lesion. In this study we analyzed the feasibility of advanced ultrasound techniques such as sono-elastography (SE) and contrast enhancement ultrasound (CEUS) in a small cohort of patients with FCD., Material and Methods: We retrospectively reviewed all clinical records and images of patients with drug resistant epilepsy who underwent at least one advanced sonographic technique (SE and/or CEUS) during ioUS guided surgery between November 2014 and October 2017. We excluded from our analysis all patients with lesions other than FCD or those who had FCD associated with other pathological entities., Results: Four patients with type IIb FCD in the right frontal lobe were evaluated. All of them underwent SE, which highlighted heterogeneous stiffness in the dysplastic foci, also multiple areas of higher consistency were detected in all patients. Three patients evaluated with CEUS had visible enhancement in the FCD. Neither SE nor CEUS were better than ioUS in the identification of lesion boundaries. In the three patients who underwent both SE and CEUS we found no correspondence between stiffer areas and enhancement in the dysplastic areas., Conclusion: Ourpreliminary report confirms the feasibility of SE and CEUS in FCD surgery and describes the imaging findings in this category of patients. Studies on larger cohorts of patients are warranted to better clarify the role of these advanced intraoperative ultrasound techniques in patients with FCD., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Objective: To localize the seizure onset zone (SOZ) and irritative zone (IZ) using electric source imaging (ESI) on intracranial EEG (iEEG) and assess their clinical value in predicting epilepsy surgery outcome in children with focal cortical dysplasia (FCD)., Methods: We analyzed iEEG data from 25 children with FCD-associated medically refractory epilepsy (MRE) who underwent surgery. We performed ESI on ictal onset to localize SOZ (ESI-SOZ) and on interictal discharges to localize IZ (ESI-IZ). We tested whether resection of ESI-SOZ and ESI-IZ predicted good surgical outcome (Engel 1). We further compared the prediction performance of ESI-SOZ and ESI-IZ to those of SOZ and IZ defined using conventional methods, i.e. by identifying iEEG-contacts showing ictal onsets (conventional-SOZ) or being the most interictally active (conventional-IZ)., Results: The proximity of ESI-SOZ (p = 0.043, odds-ratio = 3.9) and ESI-IZ (p = 0.011, odds-ratio = 7.04) to resection has higher effect on patients' outcome than proximity of conventional-SOZ (p = 0.17, odds-ratio = 1.7) and conventional-IZ (p = 0.038, odds-ratio = 2.6). Resection of ESI-SOZ and ESI-IZ presented higher discriminative power in predicting outcome (68% and 60%) than conventional-SOZ and conventional-IZ (48% and 53%)., Conclusions: Localizing SOZ and IZ via ESI on iEEG offers higher predictive value compared to conventional-iEEG interpretation., Significance: iEEG-ESI may help surgical planning and facilitate prognostic assessment of children with FCD-associated MRE., Competing Interests: Declaration of Competing Interest None of the authors have potential conflicts of interest to be disclosed., (Copyright © 2020 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: To determine the relationship between seizure onset, sleep stage and focal cortical dysplasia type 2 (FCD2) location in sleep related epilepsy (SRE)., Methods: We reviewed scalp video-EEG data of 77 patients with SRE among 130 surgically treated patients with histologically confirmed FCD2. Seizure onset was classified as occurring during NREM, REM and after arousal., Results: Sleep recordings were available for 65 patients (37 males, 7-49 years old). FCD2 was located in frontal lobe in 46 (71%) and in extra-frontal regions in 19, including the temporal lobe in 6. MRI was negative/doubtful in 35 cases. Interictal rhythmic/pseudorhythmic spike rate increased from 31% during waking to 65% during sleep. Seizure onset occurred from NREM in 46 cases (71%), mostly from stage 2, and after arousal in 14 (22%). Seizures occurring from NREM/REM sleep were significantly more frequent in frontal (89%) compared to extra-frontal location (42%), whilst arousal preceded seizure onset more often in extra-frontal (58%) compared to frontal location (7%)., Conclusions: NREM seizure onset is the most common ictal pattern in SRE due to frontal FCD2 whereas preceding arousal points to extra-frontal regions., Significance: Sleep recordings may help for FCD2 localisation and suggest topography dependent impact on sleep related epileptic networks., Competing Interests: Declaration of Competing Interest None of the Authors have potential conflicts of interest to be disclosed., (Copyright © 2019 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Aims: To investigate clinical characteristics and surgery outcomes of young children with focal cortical dysplasia (FCD) type II., Methods: Young children (onset age ≤6 years) with FCDII who underwent epileptic surgery in Children Epilepsy Center of Peking University First Hospital in 2014-2018 were followed up for at least 6 months after surgery., Results: One hundred and twelve children with FCDII were included, with median age of onset 0.9 years (0.01-5.9), who underwent surgery at 4.1 years old (0.8-16.2). Focal seizures were most frequent (90.2%) and epileptic spasms presented in 23 (20.5%) cases. Epileptic encephalopathy was not uncommon (12.5%), associated with earlier epilepsy onset and higher rate of bilateral onset on ictal EEG (OR = 0.213, 9.059; P = .041, .004). At the last follow-up, 88.4% achieved seizure-free. Before surgery, 49.1% showed moderate/severe developmental delay, associated with earlier seizure onset and higher rate of history of epileptic encephalopathy (OR = 0.740, 5.160, P = .023, .042). For 48 children with preoperatively moderate/severe developmental delay, DQ rank at 6 months postsurgery was improved in only four cases., Conclusion: For young children with FCDII, they tend to present with epileptic encephalopathies and show moderate/severe developmental delay before surgery. The seizure outcome was favorable after surgery. For children with preoperatively moderate/severe developmental delay, developmental outcome at 6 months after surgery was not satisfactory., (© 2019 The Authors. CNS Neuroscience & Therapeutics Published by John Wiley & Sons Ltd.)

The tuberous sclerosis complex (TSC), focal cortical dysplasia IIB (FCD IIB), and hemimegalencephaly (HME) exhibit similar molecular features that are dependent on the hyperactivation of the mTOR pathway. They are all associated with refractory epilepsy and the need for surgical resection with varying outcomes. The phosphorylated protein S6 (pS6) is a downstream target of mTOR, whose increased expression might indicate mTOR hyperactivation, but which is also present when there is no alteration in the pathway (such as in FCD type I). We have performed immunohistochemical marking and quantification of pS6 in resected brain specimens of 26 patients clinically and histologically diagnosed with TSC, FCD IIB, or HME and compared this data to a control group of 25 patients, to measure the extent of pS6 positivity and its correlation with clinical aspects. Our results suggest that pS6 may serve as a reliable biomarker in epilepsy and that a greater percentage of pS6 marking can relate to more severe forms of mTOR-dependent brain anomalies., (© 2021 S. Karger AG, Basel.)

Background: Focal cortical dysplasias (FCDs) are highly epileptogenic and frequently associated with medically refractory focal epilepsy. FCDs are frequently located in the frontal lobe, making its complete resection highly challenging when in proximity to the motor cortex., Case Description: We report a case of a 25-year-old woman with medically refractory epilepsy secondary to a focal cortical dysplasia in the motor cortex and extending deeply into the subcortical white matter. A detailed presurgical evaluation and invasive electroencephalographic monitoring performed at our epilepsy monitoring unit, along with the use of motor mapping, functional magnetic resonance imaging, diffusion tensor imaging, and the Stealth navigation system resulted in the complete resection of the lesion without a permanent postoperative motor deficit. The patient remained seizure-free at a 63-month follow-up while being maintained on a single antiepileptic drug., Conclusion: A detailed presurgical evaluation, accurate mapping of the functional and dysplastic cortex, and a well-planned tailored and complete surgical resection of the cortical dysplasia can result in a favorable outcome with relatively little risk of postoperative neurologic deficit., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Recent studies suggested a possible association between malformations of cortical development and microvascular density. In this study we aimed to further elucidate the relation between microvascular density and cortical developmental abnormalities in a cohort of 97 patients with epilepsy and histologically proven mild malformation of cortical development (mMCD), focal cortical dysplasia (FCD) or tuberous sclerosis complex (TSC). Surgical tissue samples were analyzed with quantitative measures of vessel density, T-cell response, microglial activation and myelin content. Subsequently, the results were compared to an age- and localization matched control group. We observed an increase in microvasculature in white matter of TSC cortical tubers, which is linked to inflammatory response. No increase was seen in mMCD or FCD subtypes compared to controls. In mMCD/FCD and tubers, lesional cortex and white matter showed increased vascular density compared to perilesional tissues. Moreover, cortical vessel density increased with longer epilepsy duration and older age at surgery while in controls it decreased with age. Our findings suggest for that the increase in white matter vascular density might be pathology-specific rather than a consequence of ongoing epileptic activity. Increased cortical vessel density with age and with longer epilepsy duration in mMCD/FCD's and tubers, however, could be a consequence of seizures., (Copyright © 2019. Published by Elsevier Ltd.)

Purpose: Focal cortical dysplasia (FCD) is one of the major causes of drug-resistant epilepsy. Surgery has proved to be the treatment of choice, however up to a third of patients experience only partial resection. Ill-defined borders and lesions embedded in eloquent areas are two of the main drawbacks of FCD surgery. Preliminary experiences with intraoperative ultrasound (ioUS) have proved its feasibility and potential. We analyzed FCD' ioUS findings in our patients with FCD and compared them with magnetic resonance (MRI) ones., Methods: We retrospectively reviewed all records of patients with focal medically refractory epilepsy who underwent ioUS guided surgery between November 2014 and October 2017. Lesions other than FCD or FCD associated with other pathological entities were not considered. Patients' preoperative MRI and ioUS features were analyzed according to up-to-date literature and than compared., Results: A homogeneous population of five patients with type IIb FCD was evaluated. Focal cortical thickening and cortical ribbon hyper-intensity, blurring of the grey-white matter junction and hyper-intensity of the subcortical white matter on T2-weighted/FLAIR images were present in all patients. Cortical features had a complete concordance between ioUS and MRI. In particular ioUS thickening and hyper-echogenicity of cortical ribbon were identified in all cases (100%). Contrary, hyper-echoic subcortical white matter was detected in 60% of the patients. IoUS images resulted in clearer lesion borders than MRI images., Conclusion: Our study confirms the potentials of ioUS as a valuable diagnostic tool to guide FCD surgeries., (Copyright © 2019. Published by Elsevier Ltd.)

Background and Purpose: Focal cortical dysplasia (FCD) is one of the most common causes of drug resistant epilepsy. Our aim was to evaluate the role of presurgical noninvasive multimodality imaging techniques in selecting patients with refractory epilepsy and focal cortical dysplasia for epilepsy surgery and the influence of the imaging modalities on long-term seizure freedom., Materials and Methods: We performed a retrospective analysis of data of 188 consecutive patients with FCD and refractory epilepsy with at least 2 years of postsurgery follow-up. Predictors of seizure freedom and the sensitivity of neuroimaging modalities were analyzed., Results: MR imaging showed clear-cut FCD in 136 (72.3%) patients. Interictal FDG-PET showed focal hypo-/hypermetabolism in 144 (76.6%); in 110 patients in whom ictal SPECT was performed, focal hyperperfusion was noted in 77 (70.3%). Focal resection was the most common surgery performed in 112 (59.6%). Histopathology revealed FCD type I in 102 (54.3%) patients. At last follow-up, 124 (66.0%) were seizure-free. Complete resection of FCD and type II FCD were predictors of seizure freedom. Localization of FCD on either MR imaging or PET or ictal SPECT had the highest sensitivity for seizure freedom at 97.5%. Among individual modalities, FDG-PET had the highest sensitivity (78.2%), followed by MR imaging (75.8%) and ictal SPECT (71.8%). The sensitivity of MR imaging to localize type I FCD (60.8%) was significantly lower than that for type II FCD (84.8%, P < .001). Among 37 patients with subtle MR imaging findings and a focal FDG-PET pattern, 30 patients had type I FCD., Conclusions: During presurgical multimodality evaluation, localization of the extent of the epileptogenic zone in at least 2 imaging modalities helps achieve seizure freedom in about two-thirds of patients with refractory epilepsy due to FCD. FDG-PET is the most sensitive imaging modality for seizure freedom, especially in patients with type I FCD., (© 2019 by American Journal of Neuroradiology.)

Focal cortical dysplasia (FCD) was first described as a distinct neuropathological entity in 1971 by Taylor and colleagues. FCD is thought to be an embryological migration disorder and is thus considered a non-progressive, unchangeable disease throughout life. A 9-year-old right-handed boy was referred from a local hospital for medically intractable epileptic seizures. Serial magnetic resonance images (MRI) showed intensity changes that indicated exacerbation and remission. After presurgical evaluations including intracranial video-electroencephalogram monitoring, we performed a lesionectomy aided by MRI and epileptic focus resection. He has been free from seizures for more than 3 years. Neuropathological findings showed FCD type Ib. We surgically treated a patient with FCD, which showed MRI intensity changes indicating exacerbation and remission. Although FCD type Ib is generally invisible on MRI, in this patient, changes in intensity on MRI made FCD type Ib visible.

Competing Interests: None

The aim of this study was to evaluate whether ganglioglioma (GGL), dysembryoplastic neuroepithelial tumour (DNET) and FCD (focal cortical dysplasia) are distinguishable through diffusion tensor imaging. Additionally, it was investigated whether the diffusion measures differed in the perilesional (pNAWM) and in the contralateral normal appearing white matter (cNAWM). Six GGLs, eight DNETs and seven FCDs were included in this study. Quantitative diffusion measures, that is, axial, radial and mean diffusivity and fractional anisotropy, were determined in the lesion identified on isotropic T2 or FLAIR-weighted images and in pNAWM and cNAWM, respectively. DNET differed from FCD in mean diffusivity, and GGL from FCD in radial diffusivity. Both types of glioneuronal tumours were different from pNAWM in fractional anisotropy and radial diffusivity. For identifying the tumour edges, threshold values for tumour-free tissue were investigated with receiver operating characteristic analyses: tumour could be separated from pNAWM at a threshold ≤ 0.32 (fractional anisotropy) or ≥ 0.56 (radial diffusivity) *10 -3 mm 2 /s (area under the curve 0.995 and 0.990 respectively). While diffusion parameters of FCDs differed from cNAWM (radial diffusivity (*10 -3  mm/s 2 ): 0.74 ± 0.19 vs. 0.43 ± 0.05; corrected p-value < 0.001), the pNAWM could not be differentiated from the FCD.

Objective: To evaluate prospectively the informative/prognostic value of epileptic discharges in the post-resection ECoGs of children with drug-resistant epilepsies and Focal Cortical Dysplasia type II (FCD-II)., Methods: Included were consecutive patients with focal epilepsies and suspected FCD-II who were planned for single-stage epilepsy surgery based on non-invasive presurgical evaluation results. Intraoperative ECoGs were recorded using a 32-channel system with strip- and/or grid-electrodes. Spikes were defined as transients with a mainly negative component and duration of 20-70 ms. Fast activity was defined as rhythmic bursts of polyspikes >13 Hz. All ECoGs were analysed visually. The significance of both spikes and fast activity in the post-resection ECoG for seizure outcomes 24 months after surgery was evaluated., Results: Data from 18 patients (five girls) were analysed. 10/18 patients (55.6%) showed spikes in their post-resection ECoGs, five of them showed additional fast activity. 24 months after surgery, 12/18 patients (66.7%) were seizure-free. There was a significant correlation between unfavorable seizure outcomes and fast activity in the post-resection ECoGs (p = 0.009), whereas spikes alone were not predictive (p = 0.502)., Conclusion: Even when recorded with non-sophisticated techniques, presence of fast activity in post-resection ECoGs might be a valid negative outcome-predictor after surgery in paediatric patients with FCD-II associated drug-resistant epilepsies., Significance: Fast activity recorded with a relatively simple ECoG equipment seems also to have prognostic significance and by this might be an alternative to HFOs recorded with highly sophisticated and expensive technologies., (Copyright © 2018 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Background: Early cerebral injury has a close relationship with epilepsy and focal cortical dysplasia Ⅲd. We investigated children with focal cortical dysplasia Ⅲd who underwent surgery for epilepsy., Methods: We selected 49 patients from among 260 pediatric patients who had undergone epilepsy surgery, analyzing their clinical materials and pathology data. The selected patients had been followed for more than two years., Results: The 49 patients were divided into seven groups based on different early brain injuries. There was a significant difference (P < 0.05) between Engel class I ratio of cerebral hemorrhage group (84.6%) and that of central nervous system infection group (42.1%) in two to eight years follow-up. The patients with prior cerebral hemorrhage had a wider scope (P < 0.05) of brain damage than those in the brain infection and febrile convulsion groups. Secondary polymicrogyria commonly existed. Neuron islands were located adjacent to polymicrogyria in cerebral hemorrhage and brain trauma patients, and missing neuronal laminations beside the polymicrogyria was noted in others., Conclusions: In children with focal cortical dysplasia Ⅲd, individuals with cerebral hemorrhage within the perinatal period exhibited a wider range of brain lesions, while the postoperative follow-up outcome was better. Secondary polymicrogyria existed along with focal cortical dysplasia Ⅲd and is related to the developmental lesion. The processes of secondary polymicrogyria caused by different early brain injuries might be different., (Copyright © 2018. Published by Elsevier Inc.)

Purpose: Focal cortical dysplasia (FCD) is the major cause of focal intractable epilepsy in childhood. Here we analyze the factors influencing the success of surgical treatment in a large cohort of children with histologically ascertained FCD., Method: A retrospective study of the effects of FCD type, surgical intervention, and age at surgery in a pediatric cohort., Results: A total of 113 patients (71 male; mean age at surgery 10.3 years; range 0-18) were analyzed; 45 had undergone lesionectomy, 42 lobectomy, 18 multi-lobectomy, and eight hemispherotomy. Complete seizure control (Engel Ia) was achieved in 56% after two years, 52% at five years, and 50% at last follow-up (18-204 months). Resections were more extensive in younger patients (40% of the surgeries affecting more than one lobe in patients aged nine years or younger vs. 22% in patients older than nine years). While resections were more limited in older children, their long-term outcome tended to be superior (42% seizure freedom in patients aged nine years or younger vs. 56% in patients older than nine years). The outcome in FCD I was not significantly inferior to that in FCD II., Conclusions: Our data confirm the long-term efficacy of surgery in children with FCD and epilepsy. An earlier age at surgery within this cohort did not predict a better long-term outcome, but it involved less-tailored surgical approaches. The data suggest that in patients with an unclear extent of the dysplastic area, later resections may offer advantages in terms of the precision of surgical-resection planning., (Copyright © 2018 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

Aim: Surgery for drug resistant epilepsy (DRE) with focal cortical dysplasia (FCD) often requires multiple non-invasive as well as invasive pre-surgical evaluations and innovative surgical strategies. There is limited data regarding surgical management of people with FCD as the underlying substrate for DRE among the low and middle-income countries (LAMIC) including India., Methodology: The presurgical evaluation, surgical strategy and outcome of 52 people who underwent resective surgery for DRE with FCD between January 2008 and December 2016 were analyzed. The 2011 classification proposed by Blumcke et al., was used for histo-pathological categorization. The Engel classification was used for defining the seizure outcome. The surgical outcome was correlated with the preoperative clinical presentation, video encephalogram (VEEG) recording, magnetic resonance imaging (MRI), invasive monitoring, surgical findings as well as histopathology and the quality of life in epilepsy (QOLIE)- 89 scores., Results: Fifty-two patients underwent resective surgery for FCD (mean age at onset of seizure: 7.94 ± 6.23 years; duration of seizures prior to surgery: 12.95 ± 9.56 years; and, age at surgery: 20.88 ± 12.51 years). The following regional distribution was found; temporal-24 (language-13), frontal-15 (motor cortex- 5), parietal-5 (sensory cortex-4), occipital-1 and multilobar-7. Forty-seven percent of the cases had FCD in the right hemisphere and 53% had FCD in the left hemisphere. Invasive monitoring was performed for identification of the epileptogenic zone (EZ) as well as eloquent cortex in 7 cases and an intra-operative electro-corticography (ECoG) was used in 32 cases. Histopathology revealed the following distribution; FCD IA-4, IB- 1, IC-5, IIA-8, IIB-18, IIIA-13, IIIB -1, IIIC-1 and IIID-1. After a median follow up of 3.7 years after surgery, 84% of patients had Engel's Ia outcome. QOLIE-89 scores improved from 38.33 ± 4.7 (31.14-49.03) before surgery to 75.21 ± 8.44 (56.49-90.49) after surgery (P < 0.001). The younger age of the patient (<20 years) at surgery (P = 0.013), a lower pre-operative score (<9) on seizure severity scale (P = 0.012), focal discharges without propagation on ictal VEEG (P < 0.001), absence of acute post-operative seizures (P < 0.001) and Type II FCD (P = 0.045) were the significant predictors for a favorable seizure outcome., Conclusion: Surgical management of people with DRE and FCD is possible in countries with limited resources. Meticulous pre-surgical evaluation to localize the epileptogenic zone and complete resection of the focus and lesion can lead to the cure or control of epilepsy; and, improvement in the quality of life was observed along with seizure-free outcome., Competing Interests: There are no conflicts of interest

Objectives: There are different neurophysiological markers of the Epileptogenic Zone (EZ), but their sensitivity and specificity for the EZ is not known in Focal Cortical Dysplasia (FCD) patients., Methods: We studied patients with FCD who underwent stereoelectroencephalography (SEEG) and surgery. We marked in the SEEG: (a) typical and atypical interictal epileptiform patterns, (b) ictal onset patterns, and (c) rates of ripples (80-250 Hz) and fast ripples (FRs) (>250 Hz). High frequency oscillations were marked automatically during one hour of deep sleep. Surgical outcome was defined as good (Engel I) or poor (Engel II-IV). We computed the sensitivity and, as a measure of specificity, the false positive rate to identify the EZ, and compared them across the different neurophysiological markers., Results: We studied 21 patients, 19 with FCD II. Ictal and typical interictal pattern were the markers with highest sensitivity, while the atypical interictal pattern had the lowest. We found no significant difference in specificity among markers. However, there is a tendency that FRs had the lowest false positive rate., Conclusion: The typical interictal pattern has the highest sensitivity. The clinical use of FRs is limited by their low sensitivity., Significance: We suggest to analyze the typical interictal pattern first. FRs should be analyzed in a second step. If, for instance, a focus with FRs and no typical interictal pattern is found, this area could be considered for resection., (Copyright © 2018 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Background: Epilepsy surgery for focal cortical dysplasia type II (FCD II) offers good chances for seizure freedom, but remains a challenge with respect to lesion detection, defining the epileptogenic zone and the optimal resection strategy. Integrating results from magnetic source imaging from magnetoencephalography (MEG) with magnetic resonance imaging (MRI) including MRI postprocessing may be useful for optimizing these goals., Methods: We here present data from 21 adult FCD II patients, investigated during a 10 year period and evaluated including magnetic source imaging. 16 patients had epilepsy surgery, i.e. histopathologically verified FCD II, and a long follow up. We present our analysis of epileptogenic zones including MEG in relation to structural data according to MRI data and relate these results to surgical outcomes., Results: FCD II in our cohort was characterized by high MEG yield and localization accuracy and MEG showed impact on surgical success-rates. MEG source localizations were detected in 95.2% of patients and were as close as 12.3 ± 8,1 mm to the MRI-lesion. After a mean follow up of >3 years, we saw >80% Engel I outcomes, with more favourable outcomes when the MEG source was completely resected (Fishers exact test 0,033)., Conclusion: We argue for a high value of conducting a combined MEG-MRI approach in the presurgical workup and the resection strategy in patients with FCD II related epilepsy.

Small bottom-of-sulcus focal cortical dysplasias (BOS-FCD) type IIb are intrinsically epileptogenic lesions often responsible for pharmacoresistant epilepsy. They are increasingly well demarcated in vivo from surrounding cortex and white matter by 3 T magnetic resonance imaging (MRI). These facts and frequent seizure freedom after just narrow resections allow questioning the classical concept of epilepsy surgery in which the epileptogenic lesion is generally considered only one part of the epileptogenic zone and the resection volume categorically has to exceed lesion limits. This study approaches this question by analyzing procedures of strongly lesion focused stereotactic radiofrequency thermocoagulation (L-RFTC) applied to BOS-FCD IIb. Seven patients with BOS-FCD IIb were treated, three had invasive EEG recordings prior to L-RFTC, all had intraoperative stereotactic EEG-recordings. Perilesional epileptic discharges (PLD) were documented in all patients. Coagulation was planned based on MRI, the maximum extension beyond lesion limits due to PLD was 4.8 mm. Although in all patients other areas of PLD remained uncoagulated, seizure freedom was achieved in four of five patients with complete lesion coagulation. In summary, due to the minimal extensions of lesion coagulations, current experience with L-RFTC of BOS-FCD IIb is not yet sufficient to rebut the significance of PLD. It encourages, however, further research on even stronger MRI guidance and possibly even ignorance of PLD in BOS-FCD IIb. It appears possible that in some BOS-FCD IIB the complete epileptogenic zone (according to Lüders) might lie inside the MRI visible lesion. This would influence the understanding of the concept of cortical zones., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Multinodular and vacuolating neuronal tumor (MVNT) is a new pattern of neuronal tumour included in the recently revised WHO 2016 classification of tumors of the CNS. There are 15 reports in the literature to date. They are typically associated with late onset epilepsy and a neoplastic vs. malformative biology has been questioned. We present a series of ten cases and compare their pathological and genetic features to better characterized epilepsy-associated malformations including focal cortical dysplasia type II (FCDII) and low-grade epilepsy-associated tumors (LEAT). Clinical and neuroradiology data were reviewed and a broad immunohistochemistry panel was applied to explore neuronal and glial differentiation, interneuronal populations, mTOR pathway activation and neurodegenerative changes. Next generation sequencing was performed for targeted multi-gene analysis to identify mutations common to epilepsy lesions including FCDII and LEAT. All of the surgical cases in this series presented with seizures, and were located in the temporal lobe. There was a lack of any progressive changes on serial pre-operative MRI and a mean age at surgery of 45 years. The vacuolated cells of the lesion expressed mature neuronal markers (neurofilament/SMI32, MAP2, synaptophysin). Prominent labelling of the lesional cells for developmentally regulated proteins (OTX1, TBR1, SOX2, MAP1b, CD34, GFAPδ) and oligodendroglial lineage markers (OLIG2, SMI94) was observed. No mutations were detected in the mTOR pathway genes, BRAF, FGFR1 or MYB. Clinical, pathological and genetic data could indicate that MVNT aligns more with a malformative lesion than a true neoplasm with origin from a progenitor neuro-glial cell type showing aberrant maturation., (© 2017 The Authors. Brain Pathology published by John Wiley & Sons Ltd on behalf of International Society of Neuropathology.)

Objective: Focal cortical dysplasia (FCD) is one important cause of drug-resistant epilepsy potentially curable by epilepsy surgery. We investigated the options of using neuronavigation and intraoperative magnetic-resonance tomographical imaging (MRI) to avoid residual epileptogenic tissue during resection of patients with FCD II to improve seizure outcome., Methods: Altogether, 24 patients with FCD II diagnosed by MRI (16 female, 8 male; mean age 34 ± 10 years) suffered from drug-resistant electroclinical and focal epilepsy for a mean of 20.7 ± 5 years. Surgery was performed with preoperative stereoelectroencephalography (in 15 patients), neuronavigation, and intraoperative 1.5T-iopMRI in all 24 investigated patients., Results: In 75% of patients (18/24), a complete resection was performed. In 89% (16/18) of completely resected patients, we documented an Engel I seizure outcome after a mean follow-up of 42 months. All incompletely resected patients had a worse outcome (Engel II-III, P < 0.0002). Patients with FCD IIB had also significant better seizure outcome compared with patients diagnosed as having FCD IIA (82% vs. 28%, P < 0.02). In 46% (11/24) of patients, intraoperative second-look surgeries due to residual lesions detected during the intraoperative MRI were performed. In these 11 patients, there were significant more completely seizure free patients (73% vs. 38% Engel IA), compared with 13 patients who finished surgery after the first intraoperative MRI (P < 0.05)., Conclusions: Excellent seizure outcome after surgery of patients with FCD II positively correlated with the amount of resection, histologic subtype, and the use of intraoperative MRI, especially when intraoperative second-look surgeries were performed., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objective: Focal Cortical Dysplasias (FCDs) represent a common architectural cortical disorder underlying drug-resistant focal epilepsy. So far, studies aimed at evaluating whether age at surgery is a factor influencing surgical outcome are lacking, so that data on the comparison between patients harboring Type II FCD operated at younger age and those operated at adult age are still scarce. We compared presurgical clinical features and surgical outcomes of patients with histopathologically diagnosed Type II FCD undergoing surgery at an earlier age with those operated after 20 years of age., Methods: We retrospectively analyzed 1660 consecutive patients operated at the "Claudio Munari" Epilepsy Surgery Centre. There were 289 patients (17.4%) with a neuropathological diagnosis of Type II FCD. We included two different groups of patients, the first one including patients operated on at less than 6years, the second sharing the same seizure onset age but with delayed surgery, carried out after the age of 20. Seizure characteristics and, neuropsychological and postoperative seizure outcomes were evaluated by study group., Results: Forty patients underwent surgery before the age of 6 and 66 patients after the age of 20. Surgical outcome was favorable in the whole population (72.6% were classified in Engel's Class Ia+Ic), independently from age at surgery. In the children group, 32 patients were classified in Class I, including 30 (75%) children in classes Ia and Ic. In the adult group, 53 belonged to Class I of whom 47 (71%) were in classes Ia and Ic. The percentage of permanent complications, the surgical outcomes, and AED withdrawal did not significantly differ by study group., Conclusion: Our results indicate that there is no difference between the groups, suggesting that outcome depends mainly on the histological findings and not on timing of surgery., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Type II focal cortical dysplasia (FCD II) is a malformation of cortical development, frequently associated with intractable epilepsy, characterised by cortical dyslamination, dysmorphic neurons (DNs) and balloon cells (BCs). We investigated the expression of pS6 (downstream target) and pPDK1-pAkt (upstream targets) as evidence for mTOR pathway activation and their co-expression with Interleukin-1β in FCD II surgical specimens and compared the findings with control non-epileptic tissue, non-malformed epileptic tissue or acquired epilepsy-Rasmussen's Encephalitis (RE) occasionally presenting pS6 and Interleukin-1β positive abnormal neurons. Downstream mTOR activation was demonstrated in almost all abnormal cells in both FCD II and RE. Conversely, upstream activation in FCD II was observed in the majority of BCs, in a proportion of DNs, not presenting Interleukin-1β expression, but not at all in RE scattered abnormal neurons. Based on these findings we suggest that the presence of BCs and DNs in FCD II could be due to a first upstream mTOR pathway PI3K-Akt-mediate event occurring very early during cortical development in the large proportion of abnormal cells; followed by the appearance of additional pS6 positive DNs promoted by the presence of a later inflammatory processes., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Introduction: Despite the success of epilepsy surgery, recent reports suggest a decline in surgical numbers. We tested these trends in our cohort to elucidate potential reasons., Patients and Methods: Presurgical, surgical and postsurgical data of all patients undergoing presurgical evaluation in between 1990 and 2013 were retrospectively analysed. Patients were grouped according to the underlying pathology., Results: A total of 3060 patients were presurgically studied, and resective surgery was performed in 66.8% (n=2044) of them: medial temporal sclerosis (MTS): n=675, 33.0%; benign tumour (BT): n=408, 20.0%; and focal cortical dysplasia (FCD): n=284, 13.9%. Of these, 1929 patients (94.4%) had a follow-up of 2 years, and 50.8% were completely seizure free (Engel IA). Seizure freedom rate slightly improved over time. Presurgical evaluations continuously increased, whereas surgical interventions did not. Numbers for MTS, BT and temporal lobe resections decreased since 2009. The number of non-lesional patients and the need for intracranial recordings increased. More evaluated patients did not undergo surgery (more than 50% in 2010-2013) because patients were not suitable (mainly due to missing hypothesis: 4.5% in 1990-1993 up to 21.1% in 2010-2013, total 13.4%) or declined from surgery (maximum 21.0% in 2010-2013, total 10.9%). One potential reason may be that increasingly detailed information on chances and risks were given over time., Conclusions: The increasing volume of the presurgical programme largely compensates for decreasing numbers of surgically remediable syndromes and a growing rate of informed choice against epilepsy surgery. Although comprehensive diagnostic evaluation is offered to a larger group of epilepsy patients, surgical numbers remain stable., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

Focal cortical dysplasia (FCD) II and I are major causes for drug-resistant epilepsy. In order to gain insight into the possible correlations between FCD II and FCD I, different clinical characteristics and immunohistochemical expression characteristics in FCD I and II were analyzed. The median age of onset and duration of epilepsy in FCD I and FCD II patients were 2.1 years and 5.3 years vs 2.4 years and 4.5 years. Therefore, the median age of onset and duration of epilepsy were similar in the two groups. Pathological lesions were predominantly located in frontal lobe in FCD II and temporal in FCD I. Significantly more signal abnormalities in FLAIR and T2 images were demonstrated in FCD II than FCD I. The rate of satisfied seizure outcome was relative higher in FCDII patients (95.12%) than that in FCDI group (84.6%). Furthermore, we detected expressions of progenitor cell proteins and the mammalian target of rapamycin (mTOR) cascade activation protein in FCDs. Results showed that sex-determiningregion Y-box 2(SOX2) , Kruppel-likefactor 4 (KLF4) and phospho-S6 ribosomal proteins (ser240/244 or ser235/236) were expressed in FCDII group but not in FCD I. Overall, this study unveils FCD I and II exhibit distinct clinical and immunohistochemical expression characteristics, revealing different pathogenic mechanisms.

Purpose: The eradication of epileptogenic lesions (e.g. focal cortical dysplasia) can be used for treatment of drug-resistant focal epilepsy, but in highly eloquent cortex areas it can also lead to a permanent neurological deficit. In such cases the neuromodulation effect of low-dose high-precision irradiation of circumscribed lesions may represent an alternative therapy., Method: A total of 10 patients with eloquent localized lesions causing pharmacoresistant focal epilepsy were prospectively identified. After informed consent, six patients agreed and were treated with risk adapted low-dose radiosurgery (SRS) or hypofractionated stereotactic radiotherapy (hfSRT). Comprehensive data concerning treatment modalities and outcome after short-term follow up (mean=16.3 months) were prospectively collected and evaluated., Results: From the six patients, two patients were treated with hfSRT (marginal dose 36 Gy) and four with SRS (marginal dose 13 Gy). Clinical target volume (CTV) ranged from 0.70 ccm to 4.32 ccm. The short-term follow-up ranged from 6 to 27 months. There were no side effects or neurological deficits after treatment. At last available follow-up two patients were seizure-free, one of them being off antiepileptic drugs. The seizure frequency improved in one and remained unchanged in three patients., Conclusion: Treatment of eloquent localized epileptogenic lesions by SRS and hfSRT showed no adverse events and an acceptable seizure outcome in this small prospective patient series. The relatively short-term follow-up comprises one of the study's drawbacks and therefore a longer follow-up should be awaited in order to evaluate the neuromodulation effect of the treatment. These preliminary results may however justify the initiation of a larger prospective trial investigating whether focused low-dose stereotactic irradiation could be an option for lesions in eloquent brain areas., (Copyright © 2016 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

The most commonly identified pathologies in patients with medically intractable epilepsy include focal cortical dysplasia, hippocampal sclerosis, tumors, and remote ischemic damage. Surgery has proven to be an effective therapeutic modality in most of such patients. The coexistence of multiple pathologies in resected tissues is well documented, particularly ganglioglioma and focal cortical dysplasia. Cases of triple pathology are, however, extraordinarily unusual. We report 2 cases of triple pathology including hippocampal sclerosis, ganglioglioma, and focal cortical dysplasia. Cases of pathologically confirmed hippocampal sclerosis diagnosed between January 2000 to December 2012 (n= 349) were reviewed, and only 2 cases (0.6%) with triple pathology were identified. The histopathologic and clinical features of these 2 cases are reviewed. The patients included a 6-year-old girl and 10-year-old boy. The former patient presented with a 4-year history of epilepsy and oppositional defiant disorder. Imaging identified a lesion in the left parahippocampal gyrus and posterior hippocampus. The latter patient presented with an 8-year history of epilepsy, attention deficient hyperactivity disease, and a pervasive developmental disorder. Imaging identified a lesion in the left posterior temporal and occipital region. Resected tissues in both patients showed a ganglioglioma (World Health Organization grade I) with accompanying focal cortical dysplasia and hippocampal sclerosis. Both patients were seizure free on antiepileptic medication at last follow-up at 20 and 38 months, respectively. The prevalence of triple pathology including hippocampal sclerosis is low (<1% in the current study). Surgical intervention for triple pathology cases anecdotally appears effective in achieving seizure control., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Objective: the objective of the study was to determine significant differences in electrocorticographic patterns for various types of focal cortical dysplasias., Material and Methods: 42 patients diagnosed with drug-resistant focal epilepsy were operated on at the Burdenko Neurosurgical Institute in the period from 2006 to 2013. Patients who were histologically diagnosed with focal cortical dysplasia (FCD) and underwent video-electroencephalography and electrocorticography were analyzed., Results: The classification of epileptiform patterns proposed by Palmini in 1995 was used. The sporadic epileptiform activity pattern was predominant in electrocorticographic studies. The continued pattern was more frequent in the case of type II focal cortical dysplasias (FCDs), both combined and isolated; burst and sporadic activity patterns prevailed in combinations in the case of type III FCDs. A uniform distribution of all pattern types of the epileptiform activity was observed in type I FCDs. The data are statistically significant for groups with sporadic and continued patterns., Conclusion: The continued epileptiform activity pattern is predominant in type II focal cortical dysplasia that corresponds to the most pronounced epileptogenesis processes of brain tissue with the presence of pathological forms of neurons. A uniform pattern distribution is observed for type I FCD. Patterns of the epileptiform activity and sporadic spike bursts are predominant in the case of type III FCDs. The sporadic activity is likely to be non-specific and almost uniformly distributed in all types of cortical dysplasias.

Objective: Focal cortical dysplasia (FCD) is currently recognized as the most common cause of neocortical pharmacoresistant epilepsy. Epilepsy surgery has become an increasingly successful treatment option. Herein, the largest patient cohort reported to date is analyzed regarding long-term outcome and factors relevant for long-term seizure control., Methods: Two hundred eleven children and adults undergoing epilepsy surgery for histologically proven FCD and a follow-up period of 2-12 years were analyzed regarding the longitudinal course of seizure control, effects of FCD type, localization, magnetic resonance imaging (MRI), timing of surgery, and postoperative antiepileptic treatment., Results: After 1 year, Engel class I outcome was achieved in 65% of patients and the percentage of seizure-free patients remained stable over the following (up to 12) years. Complete resection of the assumed epileptogenic area, lower age at surgery, and unilobar localization were positive prognostic indicators of long-term seizure freedom. Seizure recurrence was 12% after the first year, whereas 8% achieved late seizure freedom either following additional introduction of antiepileptic drugs (AEDs) (4%), a reoperation (2%), or a running down phenomenon (2%). Thirty-nine percent of patients had a reduction of AED from polytherapy to monotherapy or a complete cessation of AED treatment. Late seizure relapse was seen in nine patients during reduction of AEDs (i.e., in 12% of all patients with AED tapering); in four of them seizures persisted after reestablishment of antiepileptic medication., Significance: Postoperative long-term seizure outcome was favorable in patients with FCD and remained stable in 80% of patients after the first postoperative year. Several preoperative factors revealed to be predictive for the postoperative outcome and may help in the preoperative counseling of patients with FCD and in the selection of ideal candidates for epilepsy surgery., (Wiley Periodicals, Inc. © 2014 International League Against Epilepsy.)

Focal cortical dysplasias are a well-recognized cause of medically intractable seizures. The clinical relevance of certain subgroups of the International League Against Epilepsy (ILAE) classification scheme remains to be determined. The aim of the present work is to assess the effect of the focal cortical dysplasia type Ib and Ic histologic subtypes on surgical outcome with respect to seizure frequency. This study also provides an opportunity to compare the predictive value of the ILAE and Palmini et al classification schemes with regard to the type I focal cortical dysplasias. We retrospectively reviewed 91 focal cortical dysplasia patients (55% female; median age: 19 years (interquartile range 8-34); median seizure duration: 108 months (interquartile range 36-204)) with chronic epilepsy who underwent surgery. We compared the pathological subtypes, evaluating the patients' post-surgical outcome with respect to seizure frequency according to the Engel's classification and the ILAE outcome classification. Both the ILAE classification scheme and Palmini et al classification scheme were utilized to classify the histologic subtype. Using χ(2) and Fisher's exact tests, we compared the post-surgical outcomes among these groups. Of the 91 patients, there were 50 patients with ILAE focal cortical dysplasia type Ib, 41 with ILAE focal cortical dysplasia type Ic, 63 with Palmini et al focal cortical dysplasia type IA, and 28 with Palmini et al focal cortical dysplasia type IB. After surgery, 44 patients (48%) were seizure-free. Crude analysis revealed no significant difference between patients with subtypes of ILAE focal cortical dysplasia type I or Palmini et al focal cortical dysplasia type I concerning postoperative outcome according to the Engel and ILAE scoring systems on seizure frequency. Our findings revealed no significant difference concerning surgical outcome with respect to seizure frequency for the histologic subtypes of ILAE focal cortical dysplasia type I (Ib vs Ic) or Palmini et al focal cortical dysplasia type I (IA vs IB). In isolation, the histologic subtype of focal cortical dysplasia type I does not appear predictive of postoperative outcome.

Focal cortical dysplasia (FCD) type II is a major cause of drug-resistant epilepsy. In order to gain insight into the possible correlations between FCD II pathological pattern and different clinical characteristics (including clinical information, imaging characteristics and surgical outcomes), different clinicopathological characteristics in two types of FCD II were analyzed (especially in FCD IIb). The mean age of seizure onset and disease duration of 78 patients was 11.0 and 11.2 years, respectively. Patients with FCD type IIb had earlier seizure onset compared with those with FCD type IIa. Pathological subtype IIb was predominantly in frontal lobe and subtype IIa was predominantly seen in temporal. Type IIb demonstrated significantly more signal abnormalities in fluid attenuated inversion recovery (FLAIR) images and T2 images than Type IIa. The rate of satisfactory seizure outcome was 67.64 % in the FCD IIa group, while relative higher, 88.63 %, in the FCD IIb group. All these characteristics may assist in their earlier diagnosis and improve the predictability of surgical management.

Purpose: Over the last few decades, preferred epilepsy surgical approaches have developed from standard lobectomies to individually tailored resections. Yet, it remains uncertain how small surgical interventions can be without compromising the success of the surgery. Particularly in patients with epileptogenic lesions identified by magnetic resonance imaging (MRI), it is unresolved whether resection or destruction of the lesion suffices to eliminate the epileptogenic zone. We present a minimally invasive surgical approach that may provide insight into this issue., Methods: Two patients with pharmacoresistant epilepsy due to focal cortical dysplasia type IIB demonstrated by 3 Tesla MRI were treated with lesion-focused stereotactic radio-frequency thermo-coagulation. In both patients, pathognomonic epileptic discharges were recorded from the lesion via a stimulation device prior to coagulation. In one patient, the suspected proximity of the lesion to the pyramidal tract was verified by eliciting motor evoked potentials from the depths of the lesion., Results: Following complete and near complete lesion destruction, seizures (several per day or per week, respectively) ceased in patients A and B, with no seizures for 12 months and 5 months, respectively, at the time of this publication. Neither patient acquired persistent postoperative neurological deficits., Conclusion: The fact that seizure activity stopped after destruction of small bottom-of-sulcus dysplasias implies that in these cases, the epileptogenic zone and the epileptogenic lesion may overlap. If future studies can replicate this finding, focused lesion destruction could be a further development of individually tailored epilepsy surgery. The technique described here is especially suited for high-precision surgery close to eloquent brain structures., (Copyright © 2014 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

A 45-year-old man came to our clinic due to refractory general tonic seizure and an attack of unintended yelling. Magnetic resonance imaging (MRI) demonstrated mild cortical hyperintensity on fluid attenuated inversion recovery (FLAIR) image in the left basal frontal area. Enlargement of the left olfactory nerve was also detected below the affected gyrus. Subtotal resection of the MRI-visible epileptogenic lesion was performed without any neurological deficit. The final pathological diagnosis was focal cortical dysplasia (FCD) type IIa. Seizures and yelling attacks subsided after surgery. Extracerebral abnormalities, including cranial nerve enlargement, are common in patients with hemimegalencephaly. However, such abnormalities are rare with FCD.