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Myeloid madness: assessing diagnostic inconsistency between the new WHO and ICC schemes for myelodysplastic/myeloproliferative neoplasms
  1. Leah G Benton1,2,
  2. Michael Edward Kallen2,
  3. Jonathan L Jacobs1,2,
  4. Isaac E McCool1,2,
  5. Yi Ning2,
  6. Vu H Duong3,
  7. Rima Koka2,
  8. Zeba N Singh2
  1. 1Department of Pathology, University of Maryland Medical Center, Baltimore, Maryland, USA
  2. 2Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland, USA
  3. 3Department of Internal Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
  1. Correspondence to Dr Michael Edward Kallen, Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; mkallen{at}


The classification of haematological neoplasms recently underwent revision, generating two separate schemes—the International Consensus Classification and the fifth edition of the WHO classification. The new division into separate classification systems presents challenges for haematopathologists, haematologists/oncologists and patients. While it is too early to assess the full clinical impact, we sought to identify diagnostic discordance which may arise from applying separate classification schemes in myeloid neoplasia, and particularly in the challenging category of myelodysplastic syndrome/myeloproliferative neoplasms. A review of 64 such cases found 1 case with a significant discrepancy between the WHO and International Consensus Classification systems, and 9 cases with nominal discrepancies. Confusion from the use of conflicting diagnostic terms represents a potential source of patient harm, increased pathologist workload and burnout and erosion of clinician and patient trust.

  • myelodysplastic syndromes
  • myeloproliferative disorders
  • hematologic diseases

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  • LGB and MEK are joint first authors.

  • Handling editor Vikram Deshpande.

  • Contributors LGB, JLJ and IEMcC gathered data. LGB created a first draft of the images and content. MEK wrote the manuscript. YN and VHD provided subject matter expertise. RK directed the project. ZNS is the principal investigator and refined/edited the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.