A new edition of the WHO classification of tumours of the CNS was published in 2021. Although the previous edition of this classification was published just 5 years earlier, in 2016, rapid advances in our understanding of the molecular underpinnings of CNS tumours, including the diversity of clinically relevant molecular types and subtypes, necessitated a new classification system. Compared with the 2016 scheme, the new classification incorporates even more molecular alterations into the diagnosis of many tumours and reorganizes gliomas into adult-type diffuse gliomas, paediatric-type diffuse low-grade and high-grade gliomas, circumscribed astrocytic gliomas, and ependymal tumours. A number of new entities are incorporated into the 2021 classification, especially tumours that preferentially or exclusively arise in the paediatric population. Such a substantial revision of the WHO scheme will have major implications for the diagnosis and treatment of patients with CNS tumours. In this Perspective, we summarize the main changes in the classification of diffuse and circumscribed gliomas, ependymomas, embryonal tumours and meningiomas, and discuss how each change will influence post-surgical treatment, clinical trial enrolment and cooperative studies. Although the 2021 WHO classification of CNS tumours is a major conceptual advance, its implementation on a routine clinical basis presents some challenges that will require innovative solutions.

新版 WHO 中枢神经系统肿瘤分类于 2021 年发布。尽管该分类的前一版本仅在 5 年前发布，但在 2016 年，我们对中枢神经系统肿瘤的分子基础（包括多样性）的理解取得了快速进展临床相关的分子类型和亚型，需要一个新的分类系统。与2016年的方案相比，新的分类在许多肿瘤的诊断中纳入了更多的分子改变，并将胶质瘤重新组织为成人型弥漫性胶质瘤、儿童型弥漫性低级别和高级别胶质瘤、局限性星形细胞胶质瘤和室管膜肿瘤。2021 年分类中纳入了许多新实体，特别是优先或专门出现在儿科人群中的肿瘤。世界卫生组织计划的如此重大修改将对中枢神经系统肿瘤患者的诊断和治疗产生重大影响。在本视角中，我们总结了弥漫性和局限性胶质瘤、室管膜瘤、胚胎性肿瘤和脑膜瘤分类的主要变化，并讨论了每项变化将如何影响术后治疗、临床试验入组和合作研究。尽管 2021 年 WHO 中枢神经系统肿瘤分类是一个重大的概念性进步，但其在常规临床基础上的实施提出了一些挑战，需要创新的解决方案。室管膜瘤、胚胎肿瘤和脑膜瘤，并讨论每种变化将如何影响术后治疗、临床试验招募和合作研究。尽管 2021 年 WHO 中枢神经系统肿瘤分类是一个重大的概念性进步，但其在常规临床基础上的实施提出了一些挑战，需要创新的解决方案。室管膜瘤、胚胎肿瘤和脑膜瘤，并讨论每种变化将如何影响术后治疗、临床试验招募和合作研究。尽管 2021 年 WHO 中枢神经系统肿瘤分类是一个重大的概念性进步，但其在常规临床基础上的实施提出了一些挑战，需要创新的解决方案。