WHO CNS5 2021 classification of gliomas: a practical review and road signs for diagnosing pathologists and proper patho-clinical and neuro-oncological cooperation

Abstract

The 5 th edition of World Health Organization (WHO) Central Nervous System (CNS) tumours classification has transformed the pathological diagnosis of gliomas from purely histological to the multilayered integrated one with molecular biomarkers necessary for proper classification, risk stratification, and prognostic-predictive clinical purposes. Because of deep and important changes in taxonomy and diagnostic approach to gliomas, this manuscript is a review of WHO CNS classification 5 th edition with general testing guidance for pathologists and clinicians working in neuro-oncology.

microRNAs (miRNAs) in Glioblastoma Multiforme (GBM)—Recent Literature Review

“…GBM is characterized by the occurrence of poorly differentiated neoplastic astrocytic cells, cellular and nuclear atypia, intense mitotic activity, neoangiogenesis, vascular thrombosis, limited apoptosis, and foci of necrosis. Vascular hyperproliferation and necrosis are the basic diagnostic criteria for distinguishing GBM from lower-grade gliomas [ 50 , 51 ]. GBM most often occurs in the supraential part of the cranial cavity—in the frontal, parietal, temporal, and occipital regions—but rarely in the cerebellum [ 52 , 53 ].…”

Recapitulating the Key Advances in the Diagnosis and Prognosis of High-Grade Gliomas: Second Half of 2021 Update

“…Already, the fourth WHO edition of the classification of CNS tumors published in 2016 integrated the traditional histological classification with some parameters of molecular genetics, innovating the way in which oncologists classify CNS tumors and plan their treatment. The fifth edition of the classification of CNS tumors published in 2021 was further enriched with molecular genetic parameters that are useful for a better diagnostic and prognostic classification of HGG in the pediatric field [ 78 , 79 , 80 , 81 ]. It is easy to predict that the sixth edition of the classification, which will possibly be available in 2026, will provide the neuro-oncology community with an even more detailed description, in molecular terms, of the different types and subtypes of HGG, and more generally, of brain tumors.…”

Recent Emerging Immunological Treatments for Primary Brain Tumors: Focus on Chemokine-Targeting Immunotherapies

“…The current WHO CNS 2021 5th edition (WHO CNS5) is based on the use of complex histological and molecular approaches to establish a final pathological diagnosis and classification for brain tumors [ 21 ].…”

“…Currently “glial, glioneuronal and neuronal tumors” are grouped into a separate family and divided into six categories: (1) diffuse adult-type gliomas, (2) diffuse low-grade pediatric gliomas, (3) diffuse pediatric-type gliomas with high-grade gliomas, (4) circumscribed astrocytic gliomas, (5) glioneuronal and neuronal tumors, and (6) ependymal tumors [ 21 ]. Biological mechanisms of brain tumors are summarized in Figure 1 .…”