What is the WHO classification scheme for myelodysplastic syndrome (MDS)?

Updated: Jul 24, 2018
  • Author: Emmanuel C Besa, MD; Chief Editor: Koyamangalath Krishnan, MD, FRCP, FACP  more...
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Answer

The WHO classification scheme for MDS was published in 1999. Updates to the scheme were published in 2008 and 2016. The 2016 WHO classification of MDS is as follows [16] :

  • MDS with single-lineage dysplasia (MDS-SLD) – 1 or 2 blood cytopenias; in bone marrow, dysplasia in ≥ 10% of one cell line, < 5% blasts

  • MDS with multilineage dysplasia (MDS-MLD) – 1-3 blood cytopenias, < 1 × 109/L monocytes; in bone marrow, dysplasia in ≥ 10% of cells in ≥ 2 hematopoietic lineages < 15% ring sideroblasts (or < 5% ring sideroblasts if SF3B1 mutation present) < 5% blasts

  • MDS with ring sideroblasts (MDS-RS) – Anemia, no blasts; in bone marrow, ≥ 15% of erythroid precursors with ring sideroblasts or ≥ 5% ring sideroblasts if SF3B1 mutation is present

  • MDS with isolated del(5q) – Anemia, platelets normal or decreased; in bone marrow, unilineage erythroid dysplasia, isolated del(5q), < 5% blasts ± one other abnormality except -7/del(7q)

  • MDS with excess blasts (MDS-EB) – 1-3 blood cytopenias, 0-3 dysplastic bone marrow lineages, and 5-9% blasts in bone marrow or 2-4% blasts in blood (MDS-EB1) or 10-19% blasts in bone marrow or 5-19% blasts in blood (MDS-EB2)

  • Unclassifiable MDS – Cytopenias, ±1% blasts on at least 2 occcasions; in bone marrow, single-lineage dysplasia or no dysplasia but characteristic MDS cytogenetics, < 5% blasts

The WHO classification also includes provisional category of refractory cytopenia of childhood, with cytopenias and < 2% blasts in peripheral blood and, in bone marrow, dysplasia in 1–3 lineages and < 5% blasts.


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