MDS


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  • Clinical

    • IPSS score
      • 0: blast < 5%, good karyotype, 0-1 cytopenia
      • 0.5 for each: 5-10% blast, intermediate karyotype, 2-3 cytopenia
      • 1: poor karyotype
      • 1.5: 11-19% blast
      • 2: 20-30% blast = AML
    • risk groups (add IPSS score)
      • low: 0
      • int1: 0.5+
      • int2: 1.5+
      • high: 2.5+
    • cytopenia cutoffs
      • Hgb < 10
      • ANC < 1.8 E9
      • plt < 100
    • cytopenia (usually anemia), progresses to AML
    • need fresh specimens for high quality morphology. 2 hour delay = unsat.
    • need clinical correlation for dx. Don't diagnose when pt is on growth factors, EPO.

  • Types

  • Morphology

    • diagnostic criteria
      • classification based on blasts, dysplasia and ring sideroblast
      • blast < 20% in PB or marrow (500 diff in BM, 200 in PB)
      • need dysplasia for dx, unless cytogenetics
      • cytopenia w/o dysplasia or cytogenetics = idiopathic cytopenia of undetermined significance = monitor
    • dysplasia
      • dyserythropoiesis
        • cutoff is 10%
        • mainly nuclear: budding, internuclear bridging, karyorrhexis, multinuclear, megaloblastoid
        • cytoplasmic: ring sideroblast, vacuole, PAS positivity
      • dysgranulopoiesis
        • cutoff is 10%
        • nuclear hypolobation (pseudo Pelger-Huet)
        • hypersegmentation
        • hypogranularity, agranularity
        • pseudo Chediak Higashi granule
        • small or unusually large size
        • Auer rods
      • dysmegakaryocytopoiesis
        • cutoff is 10%, at least 30 megakaryocytes evalulated
        • micromegakaryocytes
        • multinucleated (widely separated nuclei)
        • hypolobation, nonlobation
    • marrow
      • usually hypercellular or normocellular marrow
      • aggressive features: aggregates (3-5 cells) or clusters (>5 cells) of blasts in BM (central, away from vessel and endosteal surfaces of trabeculae)
      • hypoplastic MDS (10%): hypocellular marrow, ddx toxic myelopathy, autoimmune dz
      • MDS with fibrosis (10%): significant myelofibrosis, excess blasts, aggressive. Use biopsy for blast count
    • blood
      • cytopenia, most commonly anemia
      • usually cytopenic lineage is dysplastic

  • Immunophenotype

    • erythroid dysplasia = glycophorin A plus one of the following: H ferritin, CD71, CD105

  • Molecular

    • good karyotypes
      • isolated del 5q: usually female, hypolobated/nonlobated megakaryocytes
      • isolated del 20q: erythroid and megakaryocytic lineage
      • Y loss
    • poor
      • complex karyotype: 3+ anomalies, usually include 5q or 7q loss
      • del 7q, -7
    • intermediate
      • +8
      • 17p loss: dysplastic neuts (hypolobation, vacuolation), p53
      • inv 3: increased abnormal megakaryocytes
    • requires dysplasia for dx: +8, del 20q, -Y
    • therapy related: del 7q, del 5q, t(11;16)(q23;p13.3), t(3;21)(q26.2;q22.1)
    • other
      • i(17q), t(17p)
      • del 13q, -13
      • del 11q
      • del 12p, t(12p)
      • del 9q
      • idic(X)(q13)
      • t(1;3)(p36.3;q21.2)
      • t(2;11)(p21;q23)
      • inv(3)(q21q26.2)
      • t(6;9)(p23;q34)

  • Ddx

    • B12, folate deficiency
    • drugs, chemo, toxin
      • cotrimoxazole (neutrophil hypolobation)
      • mycophenolate mofetil (erythroblastopenia)
      • GCSF (hypergranularity, hypolobation, blasts)
      • heavy metal exposure (arsenic)
    • conditions
      • congenital dyserythropoietic anemia
      • parvovirus (erythroblastopenia, giant megaloblastoid erythroblasts)
      • PNH
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