%0 Journal Article
%T Application of the International Consensus Classification and World Health Organization 5th edition classification to a series of myeloid neoplasms.
%A Chopra S
%A Bailey NG
%J Am J Clin Pathol
%V 160
%N 6
%D 2023 Dec 1
%M 37587830
%F 5.4
%R 10.1093/ajcp/aqad097
%X <B>OBJECTIVE: </B>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.<BR><B>METHODS: </B>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.<BR><B>RESULTS: </B>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.<BR><B>CONCLUSIONS: </B>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.