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Myelodysplastic syndromes (MDSs) are clonal disorders characterized initially by ineffective hematopoiesis and subsequently by the development of acute leukemias. Peripheral blood cytopenias in combination with a hypercellular bone marrow exhibiting dysplastic changes are the hallmark of MDS


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Incidence: Increases with Age
Mean age: 68 years Male-to-female ratio: 1:1
Overall: 4.1 per 100,000
Ages 50–59 years: 0.3 per 100,000
Ages 60–69 years: 15 per 100,000
Ages 70–79 years: 49 per 100,000
Ages >80 years: 89 per 100,000


Dunbar CE, Saunthararajah Y. Myelodysplastic syndromes. In: Young NS, ed. Bone Marrow Failure Syndromes. Philadelphia, PA: WB Saunders; 2000:69–98

Greenberg P et al. Blood 1997;89:2079–2088.

Erratum in: Blood 1998;91:1100. Comment in: Blood 1997;90:2843–2846, Blood 2001;98:1985


CBC with differential

Serum liver function tests, electrolytes, serum creatinine

Bone marrow biopsy and aspiration with iron stains, flow cytometry, cytogenetics

HLA typing for patients who are candidates for allogeneic stem cell transplantation

RBC folate, serum B12, serum iron/TIBC/ferritin, serum erythropoietin level (prior to RBC transfusion)

HIV testing if clinically indicated

Thyroid function tests to rule out hypothyroidism

HLA-DR15 typing to assist determination of response to immunosuppressive therapy

Evaluate patients with chronic myelomonocytic leukemia (CMML) for 5q31–33 translocations and/or PDGFRβ gene rearrangements

JAK2 mutation in patients with thrombocytosis


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Frequent Chromosomal Aberrations in MDS
Numerical Translocations Deletions
Cytogenetics (%) Cytogenetics (%) Cytogenetics (%)
+ 8 19 inv 3 7 del 5q 27
−7 15 t (1;7) 2 del 11q 7
+21 7 t (1;3) 1 del 12q 5
−5 7 t (3;3) 1 del 20q 5
    t (6;9) <1 del 7q 4
    t (5;12) <1 del 13q 2


−, Loss of chromosome; +, additional chromosome; inv, inversion; t, translocation; del, deletion

  • Clonal cytogenetic abnormalities: 30–79%

  • Deletions are more frequent than translocations

Classification Systems for MDS

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Classification Systems for MDS
French-American-British Classification of MDS
FAB Subtype % of Bone Marrow Blasts % of Peripheral Blasts
Refractory anemia (RA) <1 <5
Refractory anemia with ringed sideroblasts (RARS) <1 <5
Refractory anemia with excess blasts (RAEB) <5 5–20
Refractory anemia with excess blasts in transformation (REAB-t) ≥5 21–30
Chronic myelomonocytic leukemia (CMML) (>1000 monocytes/μL blood) <5 5–20


Bennett JM et al. Proposals for the classification of the myelodysplastic syndromes. Br J Haematol 1982;51:189–199


2008 World Health Organization Classifi cation of MDS
Subtype Blood Bone Marrow
Refractory cytopenia with unilineage dysplasia (RCUD) Single or bicytopenia Dysplasia in ≥10% of 1 cell line, <5% blasts
Refractory anemia with ring sideroblasts (RARS) Anemia, no blasts ≥15% of erythroid precursors w/ring sideroblasts, erythroid dysplasia only, <5% blasts
Refractory cytopenia with multilineage dysplasia (RCMD) Cytopenias, monocytes <1000/μL Dysplasia in ≥10% of cells in ≥2 hematopoietic lineages, ±15% ring sideroblasts, <5% blasts
Refractory anemia with excess blasts-1 (RAEB-1)

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