Characterization of gliomas: from morphology to molecules

Abstract

This article reviews the histologic and molecular characterization of gliomas, including the new "integrated diagnoses" of the World Health Organization Classification, 2016 edition. The entities reviewed within include diffuse gliomas (astrocytoma, oligodendroglioma, glioblastoma), as well as circumscribed and low-grade gliomas (angiocentric glioma, pilocytic astrocytoma, subependymal giant cell astrocytoma, pleomorphic xanthoastrocytoma, pilomyxoid astrocytoma, ependymoma, myxopapillary ependymoma, and subependymoma). Diagnostic, prognostic, and predictive biomarkers are discussed for each entity. We review how molecular testing for IDH1 and ATRX and detection of chromosome 1p/19q codeletion can be used to categorize glioblastomas as IDH-wildtype or IDH-mutant, and lower grade diffuse gliomas into three molecular groups that correlate better with patient outcomes than histologic subtyping. Pediatric diffuse gliomas are highlighted, including diffuse midline glioma, H3 K27M-mutant, and inherited germline mutations that predispose to pediatric gliomas. The utility of genomic profiling of certain gliomas is discussed, including identifying candidates for experimental therapies. This review is meant to be a concise summary of glioma characterization for the practicing pathologist.

Auxílio dos Marcadores Imuno-Histoquímico e Molecular na Classificação e Condução de Gliomas Difusos de Baixo Grau de Malignidade

“…Considerar apenas a histologia do tumor determinante no diagnóstico e nas decisões terapêuticas, no entanto, por vezes, é um método subjetivo e variável 3,9 . Porém, esse aumento progressivo do conhecimento na biologia molecular desses tumores contribuiu para a adição de novos parâmetros na classificação dos gliomas 4 .…”

Cerebellopontine Angle Anaplastic Ependymoma: A Case Report and Literature Review

“…According to the 2016 WHO classification of CNS neoplasms, ependymal tumors are being classified as WHO grade I: myxopapillary ependymoma (occurring almost exclusively in the conus-cauda-filum terminale region) and subependymoma, a benign, slowly growing intraventricular lesion with a very favourable prognosis, WHO grade II ependymoma and WHO grade III anaplastic ependymoma (Chen, 2017). Although most ependymal tumors are benign, Grade III ependymomas are characterised by hypercellularity, cellular and nuclear pleomorphism, frequent mitosis, pseudopalisading necrosis and endothelial proliferation an associated with higher risk of recurrence, or drop metastasis (Trivedi, 2017;Ferris, 2017;Sun, 2017;Takeda, 2017). Extra-CNS metastasis, although extremely rare, have been described in isolated works of the literature (Marsecano, 2017).…”

Non-Coding RNAs in Brain Tumors, the Contribution of lncRNAs, circRNAs, and snoRNAs to Cancer Development—Their Diagnostic and Therapeutic Potential

“…High-grade gliomas are characterized by uncontrolled proliferation, invasiveness, necrosis formation, lack of apoptosis, and dynamic angiogenesis [ 3 ]. These features, combined with difficult access to the tumor, mean that despite the combination of surgical treatment with radiotherapy and chemotherapy followed by Stupp protocol, only limited therapeutic success is expressed—the median survival in the case of patients diagnosed with glioblastoma (GBM)—the most aggressive type of brain cancer—is still less than two years [ 4 ].…”