Myelodysplastic Syndrome

Epidemiology


Etiology

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Physiology

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Diagnosis

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WHO Classification of Myelodysplastic Syndromes [MEDLINE]

Refractory Anemia (RA)

  • Blood Findings
  • Bone Marrow Findings
    • Eythroid Dysplasia Alone
    • <5% Blasts
    • <15% Ringed Sideroblasts

Refractory Cytopenia with Unilineage Dysplasia

  • Epidemiology: accounts for <5% of myelodysplastic syndrome cases
  • Blood Findings: one of the following
    • Refractory Anemia (see Anemia, Anemia)
    • Refractory Neutropenia
    • Refractory Thrombocytopenia
  • Bone Marrow Findings
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Refractory Anemia with Ringed Sideroblasts (RARS)

  • Epidemiology: accounts for <5% of myelodysplastic syndrome cases
  • Blood Findings
  • Bone Marrow Findings
    • Erythroid dysplasia alone
    • < 5% blasts
    • ≥ 15% ringed sideroblasts

Refractory Cytopenia with Multilineage Dysplasia (RCMD)

  • Epidemiology: accounts for 70% of myelodysplastic syndrome cases
  • Blood Findings
    • Cytopenias (bicytopenia or pancytopenia)
    • no or rare blasts
    • no Auer rods
    • < 1 billion monocytes per liter
  • Bone Marrow Findings
    • Dysplasia in ≥ 10% of cells in ≥ 2 myeloid cell lines
    • < 5% blasts
    • No Auer rods
    • <15% ringed sideroblasts

Refractory Cytopenia with Multilineage Dysplasia and Ringed Sideroblasts

  • Epidemiology: accounts for 70% of myelodysplastic syndrome cases
  • Blood Findings
    • Cytopenias (bicytopenia or pancytopenia)
    • No or rare blasts
    • No Auer rods,
    • < 1 billion monocytes per liter
  • Bone Marrow Findings
    • Dysplasia in ≥ 10% of cells in ≥ 2 myeloid cell lines
    • < 5% blasts
    • No Auer rods
    • ≥ 15% ringed sideroblastsxx

Refractory Anemia with Excess Blasts-1 (RAEB-1)

  • Epidemiology: accounts for 25% of myelodysplastic syndrome cases
  • Blood Findings
    • Cytopenias
    • < 5% blasts
    • No Auer rods
    • <1 billion monocytes per liter
  • Bone Marrow Findings
    • Unilineage or multilineage dysplasia
    • 5—9% blasts
    • No Auer rods

Refractory Anemia with Excess Blasts-2 (RAEB-2)

  • Epidemiology: accounts for 25% of myelodysplastic syndrome cases
  • Blood Findings
    • Cytopenias
    • 5—19% blasts
    • Occasional Auer rods
      < 1 billion monocytes per liter
  • Bone Marrow Findings
    • Unilineage or multilineage dysplasia
    • 10—19% blasts
    • Occasional Auer rods

Myelodysplastic Syndrome with Isolated del(5q)

  • Epidemiology: accounts for 5% of myelodysplastic syndrome cases
  • Blood Findings
    • Anemia (see Anemia, Anemia)
    • <5% Blasts
    • Platelet count normal to increased
  • Bone Marrow Findings
    • Normal-to-increased megakaryocytes with hypolobated nuclei
    • < 5% blasts
    • No Auer rods
    • Isolated del (5 q)

Myelodysplastic Syndrome, Unclassified (MDS-U)

  • Epidemiology: accounts for <5% of myelodysplastic syndrome cases
  • Blood Findings
    • Cytopenias
    • No or rare blasts
    • No Auer rods
  • Bone Marrow Findings
    • Unilineage dysplasia in granulocytes or megakaryocytes
    • <5% blasts
    • No Auer rodsx

Clinical Manifestations

Pulmonary Manifestations

  • Pulmonary Hypertension (see Pulmonary Hypertension, Pulmonary Hypertension)
    • Early Chest Series of Unexplained Pulmonary Hypertension in Myeloproliferative Disorders (2001) [MEDLINE]: 14/26 patients had platelet counts >600k
      • 12 patients had diagnosis of myeloid metaplasia with myelofibrosis
      • 5 patients had diagnosis of essential thrombocytosis
      • 6 patients had diagnosis of polycythemia vera
      • 2 patients had diagnosis of myelodysplastic sydrome
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Other Manifestations

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Treatment

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References

  • Unexplained pulmonary hypertension in chronic myeloproliferative disorders. Chest. 2001 Sep;120(3):801-8 [MEDLINE]
  • The World Health Organization (WHO) classification of the myeloid neoplasms. Blood. 2002 Oct 1;100(7):2292-302 [MEDLINE]
  • Incidence of pulmonary hypertension in patients with chronic myeloproliferative disorders. Haematologica 2004;89:245—7 [MEDLINE]
  • Pulmonary hypertension in patients with chronic myeloproliferative disorders. Eur Respir J. 2010 Jun;35(6):1396-406. doi: 10.1183/09031936.00175909 [MEDLINE]
  • Non-infectious pulmonary complications of myelodysplastic syndromes and chronic myeloproliferative disorders. Rev Mal Respir. 2011 Jun;28(6):e18-27. doi: 10.1016/j.rmr.2009.04.001. Epub 2011 Jun 8[MEDLINE]