Fifth Edition of the World Health Classification of Tumors of the Hematopoietic and Lymphoid Tissue: Myeloid Neoplasms

WHO 5th Edition Classification Project, Reza Nejati

Research output: Contribution to journalReview articlepeer-review

2 Scopus citations


In this manuscript, we review myeloid neoplasms in the fifth edition of the World Health Organization classification of hematolymphoid tumors (WHO-HEM5), focusing on changes from the revised fourth edition (WHO-HEM4R). Disease types and subtypes have expanded compared with WHO-HEM4R, mainly because of the expansion in genomic knowledge of these diseases. The revised classification is based on a multidisciplinary approach including input from a large body of pathologists, clinicians, and geneticists. The revised classification follows a hierarchical structure allowing usage of family (class)-level definitions where the defining diagnostic criteria are partially met or a complete investigational workup has not been possible. Overall, the WHO-HEM5 revisions to the classification of myeloid neoplasms include major updates and revisions with increased emphasis on genetic and molecular drivers of disease. The most notable changes have been applied to the sections of acute myeloid leukemia and myelodysplastic neoplasms (previously referred to as myelodysplastic syndrome) with incorporation of novel, disease-defining genetic changes. In this review we focus on highlighting the updates in the classification of myeloid neoplasms, providing a comparison with WHO-HEM4R, and offering guidance on how the new classification can be applied to the diagnosis of myeloid neoplasms in routine practice.

Original languageEnglish
Article number100397
Pages (from-to)100397
JournalModern Pathology
Issue number2
StatePublished - Feb 2024


  • World Health Organization
  • acute myeloid leukemia
  • clonal cytopenia of undetermined significance
  • hematopathology
  • myelodysplastic neoplasm
  • myeloid
  • myeloproliferative neoplasm
  • Myelodysplastic Syndromes/genetics
  • Myeloproliferative Disorders/diagnosis
  • Humans
  • Leukemia, Myeloid, Acute/genetics
  • Hematologic Neoplasms/diagnosis


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