AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |
Back to Blog
Nitin wadhwani google drive login12/28/2023 ![]() Prior to 2016, morphologic features drove the classification of all diffuse gliomas. Thus, if molecular testing was performed on that supratentorial ependymoma but failed to uncover a ZFTA or YAP1 fusion, it would be called “Supratentorial ependymoma, NEC.”ĭiffuse gliomas, accounting for ~70% of adult brain tumors, are the most common type of primary brain tumor to arise in adults (the most common CNS neoplasm overall is metastatic disease). NEC, on the other hand, means that the appropriate molecular testing was performed but did not provide enough useful information for further classification. For example, if a supratentorial lesion has ependymal morphology, but sequencing and methylation profiling are not available, a final diagnosis of “Supratentorial ependymoma, NOS” would be appropriate. NOS means that the molecular testing required to classify a CNS lesion is not available. Other changes in general nomenclature include “not otherwise specified (NOS)” and “not elsewhere classified (NEC)”. Finally, since a grade 2 glioma (for example) does not necessarily have the same general behavior or prognosis as a grade 2 tumor in WHO classifications of other neoplasms elsewhere in the body, the official usage is “CNS WHO grade 2” not simply “WHO grade 2.” However, for ease of reading, the latter approach is adopted in this review. ![]() Also, the term “anaplasia” is no longer employed, instead only “WHO grade 3” is used in the diagnosis. In addition, grading is now done within tumor types as part of the integrated diagnosis, so although grades still correspond to natural history, there is not necessarily perfect equivalence between the same numerical grade in different types of tumors, i.e., a grade 4 medulloblastoma does not necessarily mean the same prognosis as a grade 4 IDH wt glioblastoma. The first is that WHO grades, which were previously listed in Roman numerals, are now listed in Arabic numerals. The purpose of this review is to discuss how these updates will impact clinical care, focusing on adult-type diffuse gliomas, pediatric-type diffuse gliomas, circumscribed astrocytic gliomas, ependymal tumors, and embryonal tumors (summarized in Table 1), as these are the entities with the most dramatic changes.īefore discussing specific tumors, it is worth mentioning a few general changes in grading. The fifth edition of the WHO Classification of Central Nervous System Tumors incorporates this updated understanding of the molecular underpinnings of CNS tumors while maintaining their histopathologic roots. These rapid changes in the understanding of the molecular features that define CNS tumors fostered the Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy (cIMPACT-NOW) in 2017 to quickly provide updates in the pathological workup of CNS tumors between WHO editions. Novel techniques such as next generation sequencing, RNA expression profiling, and DNA methylation profiling have paved the way for the discovery and classification of new entities, as well as more precise classification and stratification of existing tumors. The fifth edition of the WHO Classification of Central Nervous System Tumors was released at the end of 2021, a mere 5 years after the fourth edition was published. This review addresses the most clinically relevant changes in the 2021 WHO book, including diffuse and circumscribed gliomas, ependymomas, embryonal tumors, and meningiomas. Naturally, these changes will impact how CNS tumor patients are diagnosed and treated, including clinical trial enrollment. Some entirely new tumors are in this scheme, particularly pediatric tumors. ![]() Many tumors have also been reconceptualized into new “supercategories,” including adult-type diffuse gliomas, pediatric-type diffuse low- and high-grade gliomas, and circumscribed astrocytic gliomas. The 2016 version was the first to include specific molecular alterations in the diagnoses of a few tumors, but the 2021 system greatly expanded this approach, with over 40 tumor types and subtypes now being defined by their key molecular features. Advances in the understanding of the molecular biology of central nervous system (CNS) tumors prompted a new World Health Organization (WHO) classification scheme in 2021, only 5 years after the prior iteration.
0 Comments
Read More
Leave a Reply. |