最近，有两种新的骨髓肿瘤分类方法被发布：国际共识分类（ICC）和世界卫生组织第五版分类（WHO5）。我们旨在研究这两种分类方法在患者诊断中的真实影响。我们检索了我们的机构病理数据库，并随机选择了237个骨髓肿瘤诊断病例。对于每个病例，我们分别采用了基于WHO5和ICC的分类方法。比较WHO5和ICC的诊断结果以确定它们的一致程度。应用WHO5和ICC的诊断标准后，有134例（56.5%）被分类为一致，63例（26.6%）存在术语上的差异，37例（15.6%）存在轻微的诊断差异，3例（1.3%）存在重大的诊断差异。存在轻微诊断差异的病例包括25例骨髓增生异常综合征（MDS），10例急性髓系白血病（AML）和2例髓系前体病变。存在重大诊断差异的病例包括2例根据ICC诊断为未特指的MDS，但根据WHO5的诊断为具有NPM1改变的AML和具有RBM15::MRTFA的AML，以及1例根据ICC诊断为慢性髓细胞、单核细胞白血病，但根据WHO5的诊断为具有NPM1改变的AML。本研究证实了大多数病例在这两个系统中的分类相似。考虑到这两种分类方法的总体相似性，应该进一步协调这两种分类方法，以避免混淆和多重诊断。 © 作者 2023。由牛津大学出版社代表美国临床病理学会出版。版权所有。有关权限，请发送电子邮件至：journals.permissions@oup.com。

Two new classifications of myeloid neoplasms have recently been published: the International Consensus Classification (ICC) and the 5th edition of the World Health Organization classification (WHO5). We sought to examine the real-world impact of dueling classifications on patient diagnoses.Our institutional pathology database was searched, and 237 specimens with a diagnosis of myeloid neoplasia were randomly selected. For each case, a classification based on the WHO5 and the ICC was assigned. The WHO5 and ICC diagnoses were compared to determine their degree of concordance.After applying the WHO5 and ICC diagnostic criteria, 134 (56.5%) cases were classified as concordant, 63 (26.6%) cases had terminological differences, 37 (15.6%) cases had minor diagnostic discrepancies, and 3 (1.3%) cases had major diagnostic discrepancies. Cases with minor diagnostic discrepancies included 25 cases of myelodysplastic syndrome (MDS), 10 cases of acute myeloid leukemia (AML), and 2 cases of myeloid precursor lesions. Cases with major diagnostic discrepancies included 2 cases that were diagnosed as MDS, not otherwise specified (NOS), according to the ICC but classified as AML with NPM1 alteration and AML with RBM15::MRTFA according to the WHO5 and 1 case that was characterized as chronic myelomonocytic leukemia according to the ICC and as AML with NPM1 alteration according to the WHO5.This study confirms that a majority of cases are classified similarly using the 2 systems. Given the overall similarity of the systems, future harmonization of the classifications should be pursued to avoid confusion and multiple diagnoses.© The Author(s) 2023. Published by Oxford University Press on behalf of American Society for Clinical Pathology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.