Dysembryoplastic Neuroepithelial Tumor Research Articles

Lateral Transorbital Endoscope-Assisted Resection of Anterior Temporal Lobe Neoplasm: 2-Dimensional Operative Video.

Transorbital neuroendoscopic surgery (TONES) is a minimally invasive approach, providing excellent access to extradural pathology of the sphenoid wing, orbital apex, Meckel's cave, and lateral cavernous sinus.1-10 Few cases of intradural pathology, such as gliomas or epileptic foci of the temporal lobe, have been described, apart from cadaveric anatomic studies.11-13 In this video, we present the case of a 63-year-old man with first time seizure. MRI demonstrated a fluid-attenuated inversion recovery hyperintense, noncontrast enhancing medial temporal lobe lesion consistent with low grade glioma. While frontotemporal craniotomy is the standard approach for this lesion, the TONES approach detailed in the video (the patient consented to the procedure and to the publication of his image) provided excellent access to the lesion, which minimized unnecessary trauma or removal of the lateral temporal lobe during the approach.4,14,15 The dura was closed primarily, overlayed with abdominal fat and fibrin glue, and a lumbar drain was left in place for 24 hours. The TONES approach avoided not only temporal lobe violation but also temporalis muscle disruption and any sort of external bone manipulation, which expedited the patient's recovery.16 The patient's eyelid incision was barely visible as early as postoperative day 7 with minimal ecchymosis. Postoperative MRI demonstrated a gross total resection. Pathology was consistent with a central nervous system World Health Organization grade 1 dysembryoplastic neuroepithelial tumor, a low-grade lesion with low risk of recurrence.17,18.

Enrichment of oligodendrocyte precursor phenotypes in subsets of low-grade glioneuronal tumours.

Current histological classification of low-grade glioneuronal tumours does not adequately represent their underlying biology. The neural lineage(s) and differentiation stage(s) involved and the cell state(s) affected by the recurrent genomic alterations are unclear. Here, we describe dysregulated oligodendrocyte lineage developmental programmes in three low-grade glioneuronal tumour subtypes. Ten dysembryoplastic neuroepithelial tumours, four myxoid glioneuronal tumours and five rosette-forming glioneuronal tumours were collected. Besides a comprehensive characterization of clinical features, known diagnostic markers and genomic alterations, we used comprehensive immunohistochemical stainings to characterize activation of rat sarcoma/mitogen-activated protein kinase pathway, involvement of neuronal component, resemblance to glial lineages and differentiation blockage along the stages of oligodendrocyte lineage. The findings were further complemented by gene set enrichment analysis with transcriptome data of dysembryoplastic neuroepithelial tumours from the literature. Dysembryoplastic neuroepithelial tumours, myxoid glioneuronal tumours and rosette-forming glioneuronal tumours occur at different ages, with symptoms closely related to tumour location. Dysembryoplastic neuroepithelial tumours and myxoid glioneuronal tumours contain oligodendrocyte-like cells and neuronal component. Rosette-forming glioneuronal tumours contained regions of rosette-forming neurocytic and astrocytic features. Scattered neurons, identified by neuronal nuclei antigen and microtubule-associated protein-2 staining, were consistently observed in all dysembryoplastic neuroepithelial tumours and myxoid glioneuronal tumours examined, but only in one rosette-forming glioneuronal tumour. Pervasive neurofilament-positive axons were observed only in dysembryoplastic neuroepithelial tumour and myxoid glioneuronal tumour samples. Alterations in B-Raf proto-oncogene, serine/threonine kinase, fibroblast growth factor receptor 1, fibroblast growth factor receptor 3 and platelet-derived growth factor receptor alpha occurred in a mutually exclusive manner, coinciding with strong staining of phospho-p44/42 mitogen-activated protein kinase and low apoptotic signal. All dysembryoplastic neuroepithelial tumours, myxoid glioneuronal tumours and the neurocytic regions of rosette-forming glioneuronal tumours showed strong expression of neuron-glia antigen 2, platelet-derived growth factor receptor alpha (markers of oligodendrocyte precursor cells) and neurite outgrowth inhibitor-A (a marker of developing oligodendrocytes), but lacked the expression of oligodendrocyte markers ectonucleotide pyrophosphatase/phosphodiesterase family member 6 and myelin basic protein. Notably, transcriptomes of dysembryoplastic neuroepithelial tumours were enriched in oligodendrocyte precursor cell signature, but not in signatures of neural stem cells, myelinating oligodendrocytes and astrocytes. Dysembryoplastic neuroepithelial tumour, myxoid glioneuronal tumour and rosette-forming glioneuronal tumour resemble oligodendrocyte precursor cells, and their enrichment of oligodendrocyte precursor cell phenotypes is closely associated with the recurrent mutations in rat sarcoma/mitogen-activated protein kinase pathway.

Appearance of intracranial cottonoids on intraoperative magnetic resonance imaging.

To our knowledge, this is a unique report of intraoperative magnetic resonance imaging (iMRI) of an intracranial cottonoid. The current literature describes images of cottonoids as a post-operative finding in the setting of an unintentionally retained foreign body; however, the iMRI images we present are important as the use of iMRI in the resection of complex tumors and epilepsy foci increases. This series of images was obtained during a craniotomy for tumor resection of a patient with dysembryoplastic neuroepithelial tumor. To determine both the degree of tumor resection and the amount of residual tumor, cottonoids were left in our patient's resection cavity and underwent iMRI. The ability to distinguish cottonoids in these images is important for intraoperative localization of resection margins and to prevent the retention of cottonoids.

When the Stomach Pain Is Literally “In Your Head”

Abdominal epilepsy (AE) is an extremely rare condition, classified as temporal lobe epilepsy, and is usually a diagnosis of exclusion. Temporal lobe epilepsy often has no clear cause, although it may be associated with diseases such as temporal lobe sclerosis, dysembryoplastic neuroepithelial tumours, and other benign tumours, as well as arterio-venous malformations, gliomas, defects in neuronal migration, or lesions of the cortex caused by encephalitis. AE is more common in children but has been reported in adults. AEs are characterised by recurrent and unexplained gastrointestinal symptoms such as seizure pain, nausea, bloating and diarrhoea, which improve with antiepileptic treatment. Given the vague nature of these symptoms, patients are at high risk of misdiagnosis. An electroencephalogram and neuroimaging of the brain are needed to confirm the diagnosis.
 We present the clinical case of a 67-year-old female patient who was investigated at the Gastroenterology Department for a sharp pain in the left side of the abdomen, frequent abdominal distension and gurgles, diarrhoeal episodes, weight loss, paroxysmal hallucinations, and headaches. After a thorough gastroenterological examination, consultations with a psychiatrist and a neurologist, an MRI and an EEG were performed and the patient was diagnosed with focal temporal lobe epilepsy.

"Hemispheric pilocytic astrocytoma" revisited: A comprehensive clinicopathological and molecular series emphasizing their overlap with other glioneuronal tumors.

Pilocytic astrocytomas (PA) typically exhibit distinct clinical, radiological, histopathological, and genetic features. DNA-methylation profiling distinguishes PA according to their location (infratentorial, midline, hemispheric, or spinal). In the hemispheric location, distinguishing PA from glioneuronal tumors remains a common diagnostic challenge for neuropathologists. Furthermore, the current version of the DKFZ classifier seems to have difficulty separating them from gangliogliomas. In this study, after central radiological review, we identified a histopathologically defined set of PA (histPA, n = 11) and a cohort of DNA-methylation defined PA (mcPA, n = 11). Nine out of the 11 histPA matched the methylation class of hemispheric PA, whereas 2 cases were classified at the end of the study as dysembryoplastic neuroepithelial tumors. Similarly, the mcPA cohort contained tumors mainly classified as PA (7/11), but 4 cases were classified as glioneuronal. The analysis of the 16 tumors with an integrated diagnosis of PA revealed that they affect mainly children with a wide spectrum of radiological, histopathological (i.e. a predominantly diffuse growth pattern), and genetic characteristics (large range of mitogen-activated protein kinase alterations). Based on these results, we consider hemispheric PA to be different from their counterparts in other locations and to overlap with other glioneuronal tumors, reinforcing the necessity of interpreting all data to obtain an accurate diagnosis.

A Pediatric Case Report: Dysembryoplastic Neuroepithelial Tumor or Ganglioglioma?

Dysembryoplastic neuroepithelial tumor (DNET) is a benign glioneuronal neoplasm that most frequently affects children and young adults. It can cause chronic seizures that are medically refractory. This tumor's cortical architecture and absence of a bulk effect or perilesional edema on radiographs are its defining features. The most typical manifestation of seizures is focal seizures with impaired awareness. Three DNET histologic subtypes have been identified. For either complicated or simple DNET types, histological detection of a distinct, particular glioneuronal component in brain tumor samples from individuals with medically refractory, chronic epilepsy serves as a diagnostic characteristic. We present one case of a child diagnosed with DNETs, who arrived at the hospital following seizures. The clinical, radiographic, histological, immunohistochemical, and molecular genetic characteristics of all three forms of DNETs as well as the differences between DNETs and gangliogliomas will be the main topics of this review.

Bright diffusion sign: A sensitive and specific radiologic biomarker for multinodular and vacuolating neuronal tumor

Background and purposeAccurate differentiation between multinodular and vacuolating neuronal tumor (MVNT) and dysembryoplastic neuroepithelial tumor (DNET) is important for treatment decision-making. We aimed to develop an accurate radiologic diagnostic model for differentiating MVNT from DNET using T2WI and diffusion-weighted imaging (DWI). Materials and methodsA total of 56 patients (mean age, 47.48±17.78 years; 31 women) diagnosed with MVNT (n = 37) or DNET (n = 19) who underwent brain MRI, including T2WI and DWI, were included. Two board-certified neuroradiologists performed qualitative (bubble appearance, cortical involvement, bright diffusion sign, and bright apparent diffusion coefficient [ADC] sign) and quantitative (nDWI and nADC) assessments. A diagnostic tree model was developed with significant and reliable imaging findings using an exhaustive chi-squared Automatic Interaction Detector (CHAID) algorithm. ResultsIn visual assessment, the imaging features that showed high diagnostic accuracy and interobserver reliability were the bright diffusion sign and absence of cortical involvement (bright diffusion sign: accuracy, 94.64 %; sensitivity, 91.89 %; specificity, 100.00 %; interobserver agreement, 1.00; absence of cortical involvement: accuracy, 92.86 %; sensitivity, 89.19 %; specificity, 100.00 %; interobserver agreement, 1.00). In quantitative analysis, nDWI was significantly higher in MVNT than in DENT (1.52 ± 0.34 vs. 0.91 ± 0.27, p < 0.001), but the interobserver agreement was fair (intraclass correlation coefficient = 0.321). The overall diagnostic accuracy of the tree model with visual assessment parameters was 98.21 % (55/56). ConclusionThe bright diffusion sign and absence of cortical involvement are accurate and reliable imaging findings for differentiating MVNT from DNET. By using simple, intuitive, and reliable imaging findings, such as the bright diffusion sign, MVNT can be accurately differentiated from DNET.

Long-term epilepsy associated-tumors (LEATs): what is new?

Long-term epilepsy-associated tumors (LEATs) include a series of neoplasms that commonly occur in children, adolescents, or young adults, have an astrocytic or glioneuronal lineage, are histologically benign (WHO grade1) with a neocortical localization predominantly situated in the temporal lobes. Clinically, chronic refractory epilepsy is usually the unique symptom. Gangliogliomas (GG) and dysembryoplastic neuroepithelial tumors (DNT) are the most common representative entities besides pilocytic astrocytomas (PA) and angiocentric gliomas (AG). Recent molecular studies have defined new clinicopathological entities, which are recognized by the WHO 2021 classification of brain tumors. Some of them such as diffuse astrocytoma MIB or MYBL1 altered, polymorphous low-grade neuroepithelial tumor of the young (PLNTY), and multilocular and vacuolating neuronal tumor (MVNT) are currently considered LEATs. The relationship between LEATs and epilepsy is still a matter of debate, and there is a general agreement about the beneficial effects of an early neurosurgical intervention on the clinical outcome.

Leat-associated seizures the possible role of EAAT2, pyruvate carboxylase and glutamine synthetase

BackgroundDrug-resistant epilepsy is a common condition in patients with brain neoplasms. The pathogenesis of tumor-associated seizures is poorly understood. Among the possible pathogenetic mechanisms, the increase in glutamate concentration has been proposed. Glutamate transporters, glutamine synthetase and pyruvate carboxylase are involved in maintaining the physiological concentration of glutamate in the intersynaptic spaces. In our previous research on angiocentric gliomas, we demonstrated that all tumors lacked the expression of the main glutamate transporter EAAT2, while the expression of glutamine synthetase and pyruvate carboxylase was mostly preserved. MethodsIn the present study, we evaluated the immunohistochemical expression of EAAT2, glutamine synthetase and pyruvate carboxylase in a heterogeneous series of 25 long-term epilepsy-associated tumors (10 dysembryoplastic neuroepithelial tumors, 7 gangliogliomas, 3 subependymal giant cell astrocytomas, 3 rosette forming glioneuronal tumors, 1 diffuse astrocytoma MYB- or MYBL1-altered and 1 angiocentric glioma). In order to evaluate the incidence of variants in the SLC1A2 gene, encoding EAAT2, in a large number of central nervous system tumors we also queried the PedcBioPortal. ResultsEAAT2 protein expression was lost in 9 tumors (36 %: 3 dysembryoplastic neuroepithelial tumors, 1 ganglioglioma, 3 subependymal giant cell astrocytomas, 1 diffuse astrocytoma MYB- or MYBL1-altered and 1 angiocentric glioma). Glutamine synthetase protein expression was completely lost in 2 tumors (8 %; 1 ganglioglioma and 1 diffuse astrocytoma MYB- or MYBL1-altered). All tumors of our series but rosette forming glioneuronal tumors (in which neurocytic cells were negative) were diffusely positive for pyruvate carboxylase. Consultation of the PedcBioPortal revealed that of 2307 pediatric brain tumors of different histotype and grade, 20 (< 1%) had variants in the SLC1A2 gene. Among the SLC1A2-mutated tumors, there were no angiocentric gliomas or other LEATs ConclusionsIn conclusion, unlike angiocentric gliomas where the EAAT2 loss is typical and constant, the current study shows the loss of EAAT2 expression only in a fraction of the LEATs. In these cases, we may hypothesize some possible epileptogenic role of the EAAT2 loss. The retained expression of pyruvate carboxylase may contribute to determining a pathological glutamate excess unopposed by glutamine synthetase that resulted expressed to a variable extent in the majority of the tumors. Furthermore, we can assume that the EAAT2 loss in brain tumors in general and in LEATs in particular is more conceivably epigenetic.

SURG-13. PEDIATRIC PRIMARY CENTRAL NERVOUS SYSTEM NEOPLASMS: RELATIVE UTILITY OF OPEN, MULTI-STAGE CRANIAL SURGERY

Abstract OBJECTIVE Staged surgery for skull base lesions has been utilized to facilitate maximal safe resection and optimize outcomes in pediatric patients. Despite its extensive applications, there is a paucity of information regarding open multi-stage resection of intrinsic, intra-axial neoplasms. We reviewed the literature in order to shed light on relevant considerations including the timing between surgeries, indications for staged approaches, and clinical outcomes following staged resection of pediatric intra-axial neoplasms. METHODS We conducted a literature search using PubMed, Web of Science, and Cochrane databases according to PRISMA recommendations. RESULTS Of 115 results, 7 articles were included for final analysis and consisted of 17 pediatric patients, including 6 (35%) male, 5 (29%) female, and 6 (35%) unspecified sex patients. Age ranged from 18 months to 17 years (mean 9 years). Tumor pathologies consisted of 5 (29%) astrocytomas, 2 (12%) ependymomas, 2 (12%) teratoid rhabdoid tumors, 2 (12%) oligodendromas, 1 (6%) glioma, 1 (6%) dysembryoplastic neuroepithelial tumor, 1 (6%) meningioangiomatosis, 1 (6%) pleomorphic xanthoastrocytoma, 1 (6%) ganglioglioma, and 1 (6%) germ cell tumor. Primary sites of the tumor included 4 (24%) temporal lobe, 3 (18%) thalamic, 3 (18%) thalamopeduncular, 3 (18%) frontal lobe, 2 (12%) posterior fossa, 1 (6%) cerebral hemisphere, and 1 (6%) frontoparietal lobe. Three studies reported complications, which included subtle hemiparesis, hydrocephalus, cranial nerve (CN) VI and VII palsies, truncal ataxia, and cerebellar mutism. Timing between surgeries varied from 5 days to several weeks CONCLUSION Indications for performing multi-stage resections included large tumor volume requiring multiple long stages of debulking, significant tumor vascularity, multicompartmental lesions, and planned staging due to presence of large tumors requiring resection around eloquent speech and motor cortical and white matter tract lesions that enabled use of awake functional mapping after a primary debulking performed in proximity to less eloquent regions.

The T2-FLAIR mismatch sign in oncologic neuroradiology: History, current use, emerging data, and future directions.

The T2-Fluid-Attenuated Inversion Recovery (T2-FLAIR) mismatch sign is a radiogenomic marker that is easily discernible on preoperative conventional MR imaging. Application of strict criteria (adult population, cerebral hemisphere location, and classic imaging morphology) permits the noninvasive preoperative diagnosis of isocitrate dehydrogenase (IDH)-mutant 1p/19q-non-codeleted diffuse astrocytoma with near-perfect specificity, albeit with variably low sensitivity. This leads to improved preoperative planning and patient counseling. More recent research has shown that the application of less strict criteria compromises the near-perfect specificity of the sign but remains adequate for ruling out IDH-wildtype (glioblastoma) phenotype, which bears a far grimmer prognosis compared to IDH-mutant diffuse astrocytic disease. In this review, we elaborate on the various definitions of the T2-FLAIR mismatch sign present in the literature, illustrate these with images obtained at a comprehensive cancer center, discuss the potential of the mismatch sign for application to certain pediatric-type brain tumors, namely dysembryoplastic neuroepithelial tumor and diffuse midline glioma, and elaborate upon the clinical, histologic, and molecular associations of the T2-FLAIR mismatch sign as recognized to date. Finally, the sign's correlates in diffusion- and perfusion-weighted imaging are presented, and opportunities to further maximize the diagnostic and prognostic applications of the sign in the context of the 2021 revision of the WHO Classification of Central Nervous System Tumors are discussed.

A Pediatric Case Report: Dysembryoplastic Neuroepithelial Tumor or Ganglioglioma?

Dysembryoplastic Neuroepithelial Tumor (DNET) is a benign glioneuronal neoplasm that most frequently affects children and young adults. It can cause chronic seizures that are medically refractory. This tumor’s cortical architecture and absence of a bulk effect or perilesional edema on radiographs are its defining features. The most typical manifestation of seizures is focal seizures with impaired awareness. Three DNET histologic subtypes have been identified. For either complicated or simple DNET types, histological detection of a distinct, particular glioneuronal component in brain tumor samples from individuals with medically refractory, chronic epilepsy serves as a diagnostic characteristic. We present one case of a child diagnosed with DNETs, who arrived at the hospital following seizures. The clinical, radiographic, histological, immunohistochemical, and molecular genetic characteristics characteristics of all three forms of DNETs as well as the differences between DNETs and gangliogliomas will be the main topics of this review.

An imaging review of the hippocampus and its common pathologies.

The hippocampus is a complex structure located in the mesial temporal lobe that plays a critical role in cognitive and memory-related processes. The hippocampal formation consists of the dentate gyrus, hippocampus proper, and subiculum, and its importance in the neural circuitry makes it a key anatomic structure to evaluate in neuroimaging studies. Advancements in imaging techniques now allow detailed assessment of hippocampus internal architecture and signal features that has improved identification and characterization of hippocampal abnormalities. This review aims to summarize the neuroimaging features of the hippocampus and its common pathologies. It provides an overview of the hippocampal anatomy on magnetic resonance imaging and discusses how various imaging techniques can be used to assess the hippocampus. The review explores neuroimaging findings related to hippocampal variants (incomplete hippocampal inversion, sulcal remnant and choroidal fissure cysts), and pathologies of neoplastic (astrocytoma and glioma, ganglioglioma, dysembryoplastic neuroepithelial tumor, multinodular and vacuolating neuronal tumor, and metastasis), epileptic (mesial temporal sclerosis and focal cortical dysplasia), neurodegenerative (Alzheimer's disease, progressive primary aphasia, and frontotemporal dementia), infectious (Herpes simplex virus and limbic encephalitis), vascular (ischemic stroke, arteriovenous malformation, and cerebral cavernous malformations), and toxic-metabolic (transient global amnesia and opioid-associated amnestic syndrome) etiologies.

RADIOLOGICAL SURVEILLANCE AFTER RESECTION OF LOW GRADE DYSEMBRYOPLASTIC NEUROEPITHELIAL TUMOUR AND GANGLIOGLIOMA: HOW OFTEN AND FOR HOW LONG?

Abstract AIMS Prolonged follow-up with imaging has costs both financial and psychological. We sought to review clinical and radiological follow-up for operated dysembryoplastic neuroepithelial tumour (DNET) and ganglioglioma in our unit. METHOD Retrospective review of patients diagnosed with WHO grade 1 DNET or ganglioglioma identified from our histopathology database over the last 20 years. RESULTS 44 patients were identified (DNET n=23, ganglioglioma n=21). Mean age at first surgery was 27.2 and 22.3 respectively. The median length of follow-up was 3.45 (0.84-13.9) years for DNET, and 5.03 (0.4-12.6) years for ganglioglioma. The majority of the patients had epilepsy (39/44, 88.6%) prior to surgery. Patients with DNET had 0.58 postoperative scans per year, whilst those with ganglioglioma had 1.17 scans per year. 11 (47.8%) DNET and 9 (42.9%) ganglioglioma patients had residual tumour after first surgery. None of the DNET patients had radiological change during follow-up. 9 (43%) patients with ganglioglioma had radiological change noted at least once during follow-up. 3 (13%) patients with DNET and 4 (19%) with ganglioglioma had further surgery for ongoing seizures due to residual tumour, but not for radiological progression. CONCLUSIONS Radiological change following tumour resection did not occur for DNET whereas it was more common for gangliogliomas. A reduction in postoperative imaging in our practice could be considered for operated low grade DNET and ganglioglioma, given that for all patients the indication for reoperation was seizures rather than tumour progression.

OS04.4.A LONG- AND SHORT-TERM SURVIVORS AMONG ADULT PATIENTS WITH DIFFUSE WHO GRADE 2-3 GLIOMA: CLINICAL FEATURES, MOLECULAR RECLASSIFICATION AND DNA METHYLATION PATTERNS

Abstract BACKGROUND Diffuse gliomas show considerable heterogeneity in terms of survival. The WHO classifications of 2016 and 2021 improved prognostic stratification due to the definition of biologically and clinically homogeneous tumor entities. However, further prognostic models considering clinical and molecular factors are needed to balance survival benefit with adverse treatment-related long-term effects in therapeutic decisions. MATERIALS AND METHODS Patients with diffuse gliomas of WHO grades 2 and 3 diagnosed in 2000 - 2019 have been included. Long term survivors (LTS) were defined as patients with an overall survival (OS) of &amp;gt;10 years after radiological diagnosis, whereas short-term survivors (STS) had an OS of &amp;lt;1 year. Histological diagnosis was performed by a board-certified neuropathologist. DNA methylation analysis of formalin-fixed, paraffin-embedded tumor tissue was conducted using the Illumina EPIC 850k platform. The Heidelberg Methylation Classifier was applied to obtain methylation-based diagnoses. RESULTS Of 697 patients with WHO grade 2 and 3 glioma, 182 (26.1%) were LTS, and 42 (6.0%) were STS. LTS were younger than STS (median age: 36 vs. 59.5; p&amp;lt;0.001) and had a higher Karnofsky Performance Score at diagnosis (median: 90% vs. 80%; p&amp;lt;0.001). LTS more frequently presented with epileptic seizures (p&amp;lt;0.001), while more STS had motoric (p&amp;lt;0.001), sensory (p=0.021), and visual deficits (p=0.027) as well as aphasia (p&amp;lt;0.001) and behavioral changes (p=0.009). Histological diagnoses (including pre-2016) showed astrocytic histology in 117 (70.9% LTS, 29.1% STS), oligodendroglial in 61 (93.4% LTS, 6.6% STS), oligo-astroglial in 43 (97.7% LTS, 2.3% STS) and not otherwise specified in 3 (all STS; p&amp;lt;0.001). Molecular reclassification of pre-2016 diagnoses (n = 143) yielded divergent entities in 46 (32.2%) cases. Overall, integrated molecular diagnoses included astrocytoma (isocitrate dehydrogenase [IDH]-mutant] in 65 patients (95.4% LTS and 4.6% STS), oligodendroglioma (IDH-mutant, 1p/19q-codeleted) in 64 patients (98.4% LTS and 1.6% STS), IDH-wildtype gliomas in 24 patients (100% STS), anaplastic pilocytic astrocytoma in 2 STS, diffuse midline glioma (H3K27-altered) in 1 STS, and dysembryoplastic neuroepithelial tumor in 1 LTS, while not otherwise specified diagnoses were found in 4 patients (75% LTS, 25% STS; p&amp;lt;0.001). Unsupervised clustering based on DNA methylation profiling revealed two major clusters consisting of IDH-wildtype STS (cluster A) and IDH-mutant patients (cluster B; 94.6% LTS, 5.4% STS). In cluster B, one subcluster (n = 8) contained 3/4 IDH-mt STS. Further analyses of these cases including validation with publicly available DNA methylation data are ongoing. CONCLUSION LTS and STS show distinct clinical and molecular features. Further profiling of cases with divergent survival could provide more refined prognostic stratification.

Epileptic versus neuro-oncological focus of management in pediatric patients with concurrent primary brain lesion and seizures: a systematic review.

Seizures can be a debilitating manifestation of underlying neoplastic intracranial pathology. Existing literature offers a paucity of scientific consensus regarding risk factors, seizure semiology, operative techniques, and tumor characteristics in pediatric patients with a concurrent diagnosis of primary intracranial neoplasm and seizures. To address the limited evidence in current literature, the authors systematically reviewed published literature on current clinical characteristics and management strategies for patients presenting concurrently with seizures and a newly diagnosed brain lesion, while aiming to synthesize a potential management protocol or set of recommendations for these patients. An initial search revealed 792 papers, of which 196 studies were excluded, leaving 596 studies available for abstract review. After further stratification, 546 studies were eliminated, leaving 50 studies for eligibility assessment. Of the 50 studies, 12 met the criteria for outcome extraction. The results indicate that patients with a mean age of 9 years with a newly diagnosed brain tumor and presenting symptoms of seizure are likely to present with daily seizures of the complex partial subtype, with the most likely primary epileptogenic and neoplastic foci occurring in the temporal lobe. The most common tumor subtypes were low-grade gliomas, ganglioglioma, dysembryoplastic neuroepithelial tumor, or astrocytoma. With the aim of gross-total resection, 77.54% of patients are likely to achieve seizure freedom. This study highlights the demographic, clinical, seizure, tumor, and postoperative outcomes for pediatric patients presenting with a primary brain tumor and concurrent seizures. Further prospective multicenter studies are necessary to understand and compare varying treatment approaches and to develop standardized guidelines for these patients, with the goal of optimizing neuro-oncological and seizure-related outcomes.

Clinicopathological features of dysembryoplastic neuroepithelial tumor: a case series

BackgroundDysembryoplastic neuroepithelial tumors are rare benign supratentotrial epilepsy-associated glioneuronal tumors of children and young adults. Patients have a long history of seizures. Proper surgical resection achieves long term seizure control. We describe the clinicopathological features of dysembryoplastic neuroepithelial tumor cases reported in our practice and review the published literature.MethodsAll cases of Pakistani ethnicity were diagnosed between 2015 and 2021 were included. Slides were reviewed and clinicopathological features were recorded. Follow-up was obtained. Extensive literature review was conducted.ResultsFourteen cases were reported. There were 12 males and 2 females. Age range was 9–45 years (mean 19 years). Majority were located in the temporal and frontal lobes. Duration of seizures prior to resection ranged from 2 months to 9 years with mean and median duration of 3.2 and 3 years, respectively. Histologically, all cases demonstrated a multinodular pattern, specific glioneuronal component, and floating neurons. Simple and complex forms comprised seven cases each. No significant nuclear atypia, mitotic activity, or necrosis was seen. Ki-67 proliferative index was very low. Cortical dysplasia was noted in adjacent glial tissue in four cases. Follow-up ranged from 20 to 94 months. Seizures continued following resection in all but one case but were reduced in frequency and intensity. In one case, seizures stopped completely following surgery.ConclusionClinicopathological features were similar to those in published literature. However, a marked male predominance was noted in our series. Seizures continued following resection in all but one case but were reduced in frequency and intensity. This series will help raise awareness among clinicians and pathologists in our part of the world about this seizure-associated tumor of children and young adults.

T2-FLAIR Mismatch Sign in Pediatric Low-Grade Glioma.

No qualitative imaging feature currently predicts molecular alterations of pediatric low-grade gliomas with high sensitivity or specificity. The T2-FLAIR mismatch sign predicts IDH-mutated 1p19q noncodeleted adult gliomas with high specificity. We aimed to assess the significance of the T2-FLAIR mismatch sign in pediatric low-grade gliomas. Pretreatment MR images acquired between January 2001 and August 2018 in pediatric patients with pediatric low-grade gliomas were retrospectively identified. Inclusion criteria were the following: 1) 0-18 years of age, 2) availability of molecular information in histopathologically confirmed cases, and 3) availability of preoperative brain MR imaging with non-motion-degraded T2-weighted and FLAIR sequences. Spinal cord tumors were excluded. Three hundred forty-nine patients were included (187 boys; mean age, 8.7 [SD, 4.8] years; range, 0.5-17.7 years). KIAA1549-B-Raf proto-oncogene (BRAF) fusion and BRAF p.V600E mutation were the most common molecular markers (n = 148, 42%, and n = 73, 20.7%, respectively). The T2-FLAIR mismatch sign was present in 25 patients (7.2%). Of these, 9 were dysembryoplastic neuroepithelial tumors; 8, low-grade astrocytomas; 5, diffuse astrocytomas; 1, a pilocytic astrocytoma; 1, a glioneuronal tumor; and 1, an angiocentric glioma. None of the 25 T2-FLAIR mismatch pediatric low-grade gliomas were BRAF p.V600E-mutated. Fourteen of 25 pediatric low-grade gliomas with the T2-FLAIR mismatch sign had rare molecular alterations, while the molecular subtype was unknown for 11 tumors. The T2-FLAIR mismatch sign was not observed in the common molecular alterations, BRAF p.V600E-mutated and KIAA1549-BRAF fused pediatric low-grade gliomas, while it was encountered in pediatric low-grade gliomas with rare pediatric molecular alterations.

Surgical treatment of epilepsy - Initial experience from a comprehensive epilepsy program in coastal South India.

The objectives of this study were to share our initial experience with epilepsy surgery and provide an overview on the surgical treatments of epilepsies. This was a retrospective analysis of the demographics and clinical and investigative features of patients who underwent epilepsy surgery between January 2016 and August 2021. Postoperative seizure outcome was categorized according to modified Engel's classification, and the minimum period of follow-up was 1 year. The study group included 30 patients with an age ranging from 6 years to 45 years (mean: 22.28 years, median: 20 years) and a male: female ratio of 20:10. The epilepsy duration before surgery ranged from 3 years to 32 years (median: 7 years). Majority of our patients underwent resective surgeries (28/30 = 93.3%), and disconnection procedures were done in two patients. This included one functional hemispherotomy and one posterior quadrantic disconnection. Temporal lobe resective surgery was the most common procedure (16/30 = 53.3%), followed by eight frontal lobe and two parietal lobe surgeries. Among resective surgeries, majority were lesional surgeries and the pathologies included mesial temporal sclerosis (4), dysembryoplastic neuroepithelial tumor (8), ganglioglioma (6), cavernoma (4), focal cortical dysplasia (2), gliosis (1), and one case of hypothalamic hamartoma. Intraoperative electrocorticography was used in all cases for optimizing surgical resection/disconnection. Nearly two-thirds of our patients (66.6%) had an Engel's Class I outcome, five patients had Engel's Class II outcome, three patients had Class III outcome, and one patient did not have any worthwhile improvement. Temporal lobe surgery patients had a better seizure outcome compared to extratemporal surgeries (84% vs. 74%). Overall, complications were minimal and short lasting, and comprised meningitis in three patients (5.6%) and transient worsening of hemiparesis following hemispherotomy in two patients. There was no mortality or long-lasting major morbidity in our patients. In carefully selected patients with drug-resistant epilepsy, surgery offers an excellent chance of becoming seizure-free with significant improvement in overall quality of life. Majority of the common epilepsy surgery procedures can be performed through a multidisciplinary approach even in centers with limited resources.

Dysembryoplastic Neuroepithelial Tumor (Dnet) in a Young Female: A Rare Case Presentation

Dysembryoplastic neuroepithelial tumor (DNET) is a recently described, morphologically unique, and surgically curable low grade brain tumor which is included in the WHO CNS classification as neuronal and mixed neuronal glial tumor. It is usually seen in children and young adults. This entity first described by Damas-Duport in 1998 is usually non-recurring with an excellent prognosis. We present a case of 30 year old female experiencing seizures with well defined space occupying lesion in the frontal region of brain. Contrast enhanced Magnetic Resonance Imaging was done which revealed well defined multilobulated solid cystic mass lesion in cortical/ subcortical region of left frontal lobe. Histological features suggested dysembryoplastic neuroepithelial tumor which was subsequently confirmed on immunohistochemistry by GFAP and S-100 positivity. The principal differential diagnosis is oligodendrogliomas and gangliogliomas. Patient did not receive any adjuvant therapy post operatively and showed no signs of residual disease or recurrence on magnetic resonance imaging during follow up. Patient is on phenytoin for prophylaxis of seizures.