-
Brain Pathology (Zurich, Switzerland) Jul 2022The 2021 5th edition of the WHO Classification of Tumors of the Central Nervous System reflects the discovery of genetic alterations underlying many central nervous... (Review)
Review
The 2021 5th edition of the WHO Classification of Tumors of the Central Nervous System reflects the discovery of genetic alterations underlying many central nervous system (CNS) neoplasms. Insights gained from technologic advances and novel applications in molecular diagnostics, including next-generation sequencing and DNA methylation-based profiling, coupled with the recognition of clinicopathologic correlates, have prompted substantial changes to CNS tumor classification; this is particularly true for pediatric low-grade gliomas and glioneuronal tumors (pLGG/GNTs). The 2021 WHO now classifies gliomas, glioneuronal tumors and neuronal tumors into 6 families, three of which encompass pLGG/LGNTs: "Pediatric type diffuse low-grade gliomas," "circumscribed astrocytic gliomas," and "glioneuronal and neuronal tumors." Among these are six newly recognized tumor types: "diffuse astrocytoma, MYB or MYBL1-altered"; "polymorphous low grade neuroepithelial tumor of the young (PLNTY)"; "diffuse low-grade glioma-MAPK altered"; "Diffuse glioneuronal tumor with oligodendroglioma-like features and nuclear clusters (DGONC)"; "myxoid glioneuronal tumor (MGT)"; and "multinodular and vacuolating neuronal tumor (MVNT)." We review these newly recognized entities in the context of general changes to the WHO schema, discuss implications of the new classification for treatment of pLGG/LGNT, and consider strategies for molecular testing and interpretation.
Topics: Astrocytoma; Brain Neoplasms; Central Nervous System; Central Nervous System Neoplasms; Child; Glioma; Humans; Neoplasms, Neuroepithelial; World Health Organization
PubMed: 35218102
DOI: 10.1111/bpa.13060 -
Acta Neuropathologica Communications Mar 2020Low grade gliomas are the most frequent brain tumors in children and encompass a spectrum of histologic entities which are currently assigned World Health Organisation... (Review)
Review
Low grade gliomas are the most frequent brain tumors in children and encompass a spectrum of histologic entities which are currently assigned World Health Organisation grades I and II. They differ substantially from their adult counterparts in both their underlying genetic alterations and in the infrequency with which they transform to higher grade tumors. Nonetheless, children with low grade glioma are a therapeutic challenge due to the heterogeneity in their clinical behavior - in particular, those with incomplete surgical resection often suffer repeat progressions with resultant morbidity and, in some cases, mortality. The identification of up-regulation of the RAS-mitogen-activated protein kinase (RAS/MAPK) pathway as a near universal feature of these tumors has led to the development of targeted therapeutics aimed at improving responses while mitigating patient morbidity. Here, we review how molecular information can help to further define the entities which fall under the umbrella of pediatric-type low-grade glioma. In doing so we discuss the specific molecular drivers of pediatric low grade glioma and how to effectively test for them, review the newest therapeutic agents and their utility in treating this disease, and propose a risk-based stratification system that considers both clinical and molecular parameters to aid clinicians in making treatment decisions.
Topics: Astrocytoma; Brain Neoplasms; Child; Ganglioglioma; Glioma; High-Throughput Nucleotide Sequencing; Humans; Immunohistochemistry; In Situ Hybridization, Fluorescence; MAP Kinase Signaling System; Membrane Proteins; Mitogen-Activated Protein Kinase Kinases; Molecular Diagnostic Techniques; Molecular Targeted Therapy; Neoplasm Grading; Neoplasms, Neuroepithelial; Pathology, Molecular; Polymerase Chain Reaction; Polymorphism, Single Nucleotide; Protein Kinase Inhibitors; Proto-Oncogene Proteins B-raf; Receptor, Fibroblast Growth Factor, Type 1; Tuberous Sclerosis Complex 1 Protein; Tuberous Sclerosis Complex 2 Protein; Up-Regulation; World Health Organization; ras Proteins
PubMed: 32164789
DOI: 10.1186/s40478-020-00902-z -
Acta Neuropathologica Communications Mar 2020Brain tumors represent the second most frequent etiology in patients with focal seizure onset before 18 years of age and submitted to epilepsy surgery. Hence, this... (Review)
Review
Brain tumors represent the second most frequent etiology in patients with focal seizure onset before 18 years of age and submitted to epilepsy surgery. Hence, this category of brain tumors, herein defined as low-grade, developmental, epilepsy-associated brain tumors (LEAT) is different from those frequently encountered in adults as (A): 77% of LEAT occur in the temporal lobe; (B): the vast majority of LEAT are of low malignancy and classified as WHO I°; (C): LEAT are often composed of mixed glial and neuronal cell components and present with variable growth patterns including small cysts or nodules; (D): LEAT do not share common gene driving mutations, such as IDH1 or 1p/19q co-deletions. Characteristic entities comprise the ganglioglioma (GG), the dysembryoplastic neuroepithelial tumor (DNT), the angiocentric glioma (AG), the isomorphic diffuse glioma (IDG) and the papillary glio-neuronal tumor (PGNT), representing 73.2% of 1680 tumors collected in a large German series of 6747 patients submitted to epilepsy surgery. In the realm of exciting discoveries of genetic drivers of brain tumors new genes have been also reported for LEAT. BRAF V600E mutations were linked to GG with CD34 expression, FGFR1 mutations to DNT, MYB alterations to AG and also IDG and PRKCA fusions to PGNT, suggesting the possibility to also develop a genetically driven tumor classification scheme for LEAT. Rare availability of LEAT in a single center is a challenging obstacle, however, to systematically unravel the neurobiological nature and clinical behavior of LEAT. Other challenges in need of clarification include malignant tumor progression of LEAT entities, seizure relapse in patients following bulk tumor resection and the controversial issue of associated focal cortical dysplasia as additional pathomechanism. In order to advance our understanding and promote reliable diagnostic work-up of LEAT, we recommend, therefore, international collaboration to achieve our goals.
Topics: Arachnoid Cysts; Astrocytoma; Brain Neoplasms; Central Nervous System Cysts; Dermoid Cyst; Epidermal Cyst; Epilepsies, Partial; Ganglioglioma; Humans; Molecular Diagnostic Techniques; Neoplasm Grading; Neoplasms, Neuroepithelial; Oligodendroglioma; Protein Kinase C-alpha; Proto-Oncogene Proteins; Proto-Oncogene Proteins B-raf; Proto-Oncogene Proteins c-myb; Receptor, Fibroblast Growth Factor, Type 1; Trans-Activators
PubMed: 32151273
DOI: 10.1186/s40478-020-00904-x -
Neuro-oncology May 2020Atypical teratoid/rhabdoid tumors (ATRTs) are known to exhibit molecular and clinical heterogeneity even though SMARCB1 inactivation is the sole recurrent genetic event... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Atypical teratoid/rhabdoid tumors (ATRTs) are known to exhibit molecular and clinical heterogeneity even though SMARCB1 inactivation is the sole recurrent genetic event present in nearly all cases. Indeed, recent studies demonstrated 3 molecular subgroups of ATRTs that are genetically, epigenetically, and clinically distinct. As these studies included different numbers of tumors, various subgrouping techniques, and naming, an international working group sought to align previous findings and to reach a consensus on nomenclature and clinicopathological significance of ATRT subgroups.
METHODS
We integrated various methods to perform a meta-analysis on published and unpublished DNA methylation and gene expression datasets of ATRTs and associated clinicopathological data.
RESULTS
In concordance with previous studies, the analyses identified 3 main molecular subgroups of ATRTs, for which a consensus was reached to name them ATRT-TYR, ATRT-SHH, and ATRT-MYC. The ATRT-SHH subgroup exhibited further heterogeneity, segregating further into 2 subtypes associated with a predominant supratentorial (ATRT-SHH-1) or infratentorial (ATRT-SHH-2) location. For each ATRT subgroup we provide an overview of its main molecular and clinical characteristics, including SMARCB1 alterations and pathway activation.
CONCLUSIONS
The introduction of a common classification, characterization, and nomenclature of ATRT subgroups will facilitate future research and serve as a common ground for subgrouping patient samples and ATRT models, which will aid in refining subgroup-based therapies for ATRT patients.
Topics: Consensus; DNA Methylation; Humans; Neoplasms, Neuroepithelial; Rhabdoid Tumor; Teratoma
PubMed: 31889194
DOI: 10.1093/neuonc/noz235 -
Acta Neuropathologica Nov 2021Large-scale molecular profiling studies in recent years have shown that central nervous system (CNS) tumors display a much greater heterogeneity in terms of molecularly...
Large-scale molecular profiling studies in recent years have shown that central nervous system (CNS) tumors display a much greater heterogeneity in terms of molecularly distinct entities, cellular origins and genetic drivers than anticipated from histological assessment. DNA methylation profiling has emerged as a useful tool for robust tumor classification, providing new insights into these heterogeneous molecular classes. This is particularly true for rare CNS tumors with a broad morphological spectrum, which are not possible to assign as separate entities based on histological similarity alone. Here, we describe a molecularly distinct subset of predominantly pediatric CNS neoplasms (n = 60) that harbor PATZ1 fusions. The original histological diagnoses of these tumors covered a wide spectrum of tumor types and malignancy grades. While the single most common diagnosis was glioblastoma (GBM), clinical data of the PATZ1-fused tumors showed a better prognosis than typical GBM, despite frequent relapses. RNA sequencing revealed recurrent MN1:PATZ1 or EWSR1:PATZ1 fusions related to (often extensive) copy number variations on chromosome 22, where PATZ1 and the two fusion partners are located. These fusions have individually been reported in a number of glial/glioneuronal tumors, as well as extracranial sarcomas. We show here that they are more common than previously acknowledged, and together define a biologically distinct CNS tumor type with high expression of neural development markers such as PAX2, GATA2 and IGF2. Drug screening performed on the MN1:PATZ1 fusion-bearing KS-1 brain tumor cell line revealed preliminary candidates for further study. In summary, PATZ1 fusions define a molecular class of histologically polyphenotypic neuroepithelial tumors, which show an intermediate prognosis under current treatment regimens.
Topics: Biomarkers, Tumor; Brain Neoplasms; Child; Child, Preschool; Female; Humans; Kruppel-Like Transcription Factors; Male; Neoplasms, Neuroepithelial; Oncogene Fusion; Oncogene Proteins, Fusion; Repressor Proteins
PubMed: 34417833
DOI: 10.1007/s00401-021-02354-8 -
Acta Neuropathologica Mar 2022Tumors of the central nervous system (CNS) often display a wide morphologic spectrum that has, until recently, been the sole basis for tumor classification. The...
High-grade glioma with pleomorphic and pseudopapillary features (HPAP): a proposed type of circumscribed glioma in adults harboring frequent TP53 mutations and recurrent monosomy 13.
Tumors of the central nervous system (CNS) often display a wide morphologic spectrum that has, until recently, been the sole basis for tumor classification. The introduction of the integrated histomolecular diagnostic approach in CNS tumors has facilitated a classification system that is increasingly data-driven and with improved alignment to clinical outcome. Here, we report a previously uncharacterized glioma type (n = 31) using unsupervised clustering analysis of DNA methylation array data from approximately 14,000 CNS tumor samples. Histologic examination revealed circumscribed growth and morphologic similarities to pleomorphic xanthoastrocytoma (PXA), astroblastoma, ependymoma, polymorphous neuroepithelial tumor of the young (PLNTY), and IDH-wildtype glioblastoma (GBM). Median age (46.5 years) was significantly older than other circumscribed gliomas and younger than GBM. Dimensionality reduction with uniform manifold approximation and projection (UMAP) and hierarchical clustering confirmed a methylation signature distinct from known tumor types and methylation classes. DNA sequencing revealed recurrent mutations in TP53 (57%), RB1 (26%), NF1 (26%), and NF2 (14%). BRAF V600E mutations were detected in 3/27 sequenced cases (12%). Copy number analysis showed increased whole chromosome aneuploidy with recurrent loss of chromosome 13 (28/31 cases, 90%). CDKN2A/B deletion (2/31, 6%) and MGMT promoter methylation (1/31, 3%) were notably rare events. Most tumors showed features of a high-grade glioma, yet survival data showed significantly better overall survival compared to GBM (p < 0.0001). In summary, we describe a previously uncharacterized glioma of adults identified by a distinct DNA methylation signature and recurrent loss of chromosome 13.
Topics: Astrocytoma; Brain Neoplasms; Chromosomes, Human, Pair 13; Glioma; Humans; Middle Aged; Monosomy; Mutation; Tumor Suppressor Protein p53
PubMed: 35103816
DOI: 10.1007/s00401-022-02404-9 -
Neuro-Chirurgie Feb 2021Medulloblastomas, embryonal neuroepithelial tumors developed in the cerebellum or brain stem, are mainly observed in childhood. The treatment of WHO-Grade IV tumors... (Review)
Review
Medulloblastomas, embryonal neuroepithelial tumors developed in the cerebellum or brain stem, are mainly observed in childhood. The treatment of WHO-Grade IV tumors depends on stratifications that are usually based on postoperative data, histopathological subtype, tumor extension and presence of MYC or NMYC amplifications. Recently, molecular biology studies, based on new technologies (i.e. sequencing, transcriptomic, methylomic) have introduced genetic subtypes integrated into the latest WHO-2016 neuropathological classification. According to this classification, the three genetic groups WNT, SHH, with or without mutated TP53 gene, and non-WNT/non-SHH, comprising subgroups 3 and 4, are recalled in this review. The contribution of immunohistochemistry to define these groups is specified. The four histopathological groups are detailed in comparison to the WHO-2007 classification and the molecular data: classic medulloblastoma, desmoplastic/nodular medulloblastoma, medulloblastoma with extensive nodularity, and large cell/anaplastic medulloblastoma. The groups defined on genetic and histopathological grounds are not strictly concordant. Depending on the age of the patients, their correlations are different, as well as their role in the management and prognosis of these tumors. Other embryonal tumors, for which new classifications are in progress and gliomas may be confused with a medulloblastoma and the elements of the differential diagnosis of these entities are discussed. This evolution in classification fully justifies ongoing structuring procedures such as histopathological review (RENOCLIP) and the organization of molecular biology platforms.
Topics: Adolescent; Adult; Cerebellar Neoplasms; Cerebellum; Child; Child, Preschool; Female; Humans; Male; Medulloblastoma; Neoplasms, Germ Cell and Embryonal; Prognosis; Young Adult
PubMed: 29703584
DOI: 10.1016/j.neuchi.2017.12.006 -
Acta Neuropathologica May 2023Glioneuronal tumors are a heterogenous group of CNS neoplasms that can be challenging to accurately diagnose. Molecular methods are highly useful in classifying these...
Glioneuronal tumors are a heterogenous group of CNS neoplasms that can be challenging to accurately diagnose. Molecular methods are highly useful in classifying these tumors-distinguishing precise classes from their histological mimics and identifying previously unrecognized types of tumors. Using an unsupervised visualization approach of DNA methylation data, we identified a novel group of tumors (n = 20) that formed a cluster separate from all established CNS tumor types. Molecular analyses revealed ATRX alterations (in 16/16 cases by DNA sequencing and/or immunohistochemistry) as well as potentially targetable gene fusions involving receptor tyrosine-kinases (RTK; mostly NTRK1-3) in all of these tumors (16/16; 100%). In addition, copy number profiling showed homozygous deletions of CDKN2A/B in 55% of cases. Histological and immunohistochemical investigations revealed glioneuronal tumors with isomorphic, round and often condensed nuclei, perinuclear clearing, high mitotic activity and microvascular proliferation. Tumors were mainly located supratentorially (84%) and occurred in patients with a median age of 19 years. Survival data were limited (n = 18) but point towards a more aggressive biology as compared to other glioneuronal tumors (median progression-free survival 12.5 months). Given their molecular characteristics in addition to anaplastic features, we suggest the term glioneuronal tumor with ATRX alteration, kinase fusion and anaplastic features (GTAKA) to describe these tumors. In summary, our findings highlight a novel type of glioneuronal tumor driven by different RTK fusions accompanied by recurrent alterations in ATRX and homozygous deletions of CDKN2A/B. Targeted approaches such as NTRK inhibition might represent a therapeutic option for patients suffering from these tumors.
Topics: Humans; Young Adult; Biomarkers, Tumor; Brain; Brain Neoplasms; Central Nervous System Neoplasms; Gene Fusion; Neoplasms, Neuroepithelial; Receptor Protein-Tyrosine Kinases; X-linked Nuclear Protein
PubMed: 36933012
DOI: 10.1007/s00401-023-02558-0 -
No Shinkei Geka. Neurological Surgery Sep 2023In the fifth edition central nervous system tumours volume of the WHO Classification of Tumours series, gliomas, glioneuronal tumors, and neuronal tumors are divided...
In the fifth edition central nervous system tumours volume of the WHO Classification of Tumours series, gliomas, glioneuronal tumors, and neuronal tumors are divided into six groups. The term "circumscribed" is used to refer to a relatively contained growth pattern, as compared to other inherently "diffuse" tumors. Circumscribed astrocytic gliomas include six types: pilocytic astrocytoma, high-grade astrocytoma with piloid features, pleomorphic xanthoastrocytoma, subependymal giant cell astrocytoma, chordoid glioma, and astroblastoma, -altered. The vast majority of circumscribed astrocytic gliomas harbor genetic alterations in the mitogen-activated protein kinase pathway. Here, we review the circumscribed astrocytic gliomas, including etiology, clinical and imaging features, pathology and molecular genetics, treatment, and prognosis. This study will lead to better understanding of these newly classified tumors.
Topics: Humans; Astrocytoma; Brain Neoplasms; Central Nervous System Neoplasms; Glioma; Neoplasms, Neuroepithelial
PubMed: 37743340
DOI: 10.11477/mf.1436204830 -
Handbook of Clinical Neurology 2016This chapter describes the epidemiology, pathology, molecular characteristics, clinical and neuroimaging features, treatment, outcome, and prognostic factors of the rare... (Review)
Review
This chapter describes the epidemiology, pathology, molecular characteristics, clinical and neuroimaging features, treatment, outcome, and prognostic factors of the rare glial tumors. This category includes subependymal giant cell astrocytoma, pleomorphic xanthoastrocytoma, astroblastoma, chordoid glioma of the third ventricle, angiocentric glioma, ganglioglioma, desmoplastic infantile astrocytoma and ganglioma, dysembryoplastic neuroepithelial tumor, papillary glioneuronal tumor, and rosette-forming glioneuronal tumor of the fourth ventricle. Many of these tumors, in particular glioneuronal tumors, prevail in children and young adults, are characterized by pharmacoresistant seizures, and have an indolent course, and long survival following surgical resection. Radiotherapy and chemotherapy are reserved for recurrent and/or aggressive forms. New molecular alterations are increasingly recognized.
Topics: Brain Neoplasms; Glioma; Humans; Rare Diseases; Treatment Outcome
PubMed: 26948368
DOI: 10.1016/B978-0-12-802997-8.00024-4