The upcoming 5th edition of the World Health Organization (WHO) Classification of Haematolymphoid Tumours is part of an effort to hierarchically catalogue human cancers arising in various organ systems within a single relational database. This paper summarizes the new WHO classification scheme for myeloid and histiocytic/dendritic neoplasms and provides an overview of the principles and rationale underpinning changes from the prior edition. The definition and diagnosis of disease types continues to be based on multiple clinicopathologic parameters, but with refinement of diagnostic criteria and emphasis on therapeutically and/or prognostically actionable biomarkers. While a genetic basis for defining diseases is sought where possible, the classification strives to keep practical worldwide applicability in perspective. The result is an enhanced, contemporary, evidence-based classification of myeloid and histiocytic/dendritic neoplasms, rooted in molecular biology and an organizational structure that permits future scalability as new discoveries continue to inexorably inform future editions.

即将推出的第五版世界卫生组织 (WHO) 血淋巴肿瘤分类是在单一关系数据库中对各种器官系统中出现的人类癌症进行分层分类的努力的一部分。本文总结了世界卫生组织针对骨髓和组织细胞/树突状肿瘤的新分类方案，并概述了与先前版本相比发生变化的原则和基本原理。疾病类型的定义和诊断仍然基于多种临床病理学参数，但诊断标准得到改进，并强调治疗和/或预后可行的生物标志物。虽然尽可能寻求定义疾病的遗传基础，但该分类力求保持全球范围内的实际适用性。其结果是对骨髓和组织细胞/树突状肿瘤进行了增强的、当代的、基于证据的分类，其植根于分子生物学和组织结构，随着新发现继续无情地为未来版本提供信息，允许未来的可扩展性。