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Myelodysplastic Syndromes

Definition

  • A group of clonal stem cell diseases characterized by dysplastic and ineffective hematopoiesis

Diagnostic Criteria

  • Generally result in cytopenias
  • Marrow is usually cellular
    • Displays dysplastic features (see below)
    • Occasionally hypocellular, leading to special diagnostic problems
    • Occasionally increased fibrosis, leading to special diagnostic problems
  • Increased risk of blast transformation
    • Have been considered preleukemia by some
  • Occurs mainly in older patients
  • Select specific disorders below for details

Myelodysplastic Syndromes

  Circulating Blasts Marrow Blasts Ring Sideroblasts Dysplastic Lineages Cytopenias
RCUD <1% <5% <15% Any 1 lineage 1 or 2
RARS 0 <5% ≥15% Only erythroid 1 or 2
RCMD <1% <5% Variable 2 or more lineages 1, 2 or 3
RAEB-1 <5% 5-9% Variable 1 or more 1, 2 or 3
RAEB-2 5-19% 10-19% or Auer rods Variable 1 or more 1, 2 or 3
del(5q) <1% <5% Variable Frequently hypolobated small megakaryocytes Usually 1 (anemia)
  • RCUD = refractory cytopenia (anemia, neutropenia or thrombocytopenia) with unilineage dysplasia; RARS = refractory anemia with ringed sideroblasts; RCMD = refractory cytopenia with multilineage dysplasia; RAEB = refractory anemia with excess blasts; del(5q) = 5q- syndrome
  • All MDS must not have absolute monocytosis
  • If chemotherapy or radiation therapy related, should be reported as "therapy-related myeloid neoplasm"
  • In children, consider provisional WHO entity "refractory cytopenia of childhood" for low blast count MDS
  • Myelodysplastic syndrome unclassifiable (MDS-U)
    • Must not meet criteria of any specific WHO category
    • Persistent cytopenia(s) with any of the following:
      • Unilineage marrow dysplasia with pancytopenia OR
      • <1% blasts in blood, <5% blasts in marrow and cytogenetic abnormalities but no lineage with ≥10% dysplastic forms OR
      • Findings of RCUD or RCMD but with 1% blasts in peripheral blood
        • (2-4% blasts would be classified as RAEB-1)
    • Nonclonal causes must be excluded

 

Myelodysplasia is defined by morphologic features of abnormal cellular maturation in at least one bone marrow lineage

  • Not all features are applicable to all disorders
  • Dyserythropoeisis
    • Peripheral blood erythrocyte abnormalities
      • Normocytic, normochromic anemia
      • Macrocytosis
      • Dimorphic red blood cells (RBC)
      • Basophilic stippling
      • Poikilocytosis
        • Varying shapes, frequently macro-ovalocytes
    • Bone marrow erythroid lineage abnormalties
      • Erythroid hyperplasia or hypoplasia
        • Megaloblastoid / megaloblastic changes
          • Dyssynchronous maturation of nucleus and cytoplasm of erythroid precursors
            • Nucleus lags behind cytoplasm
      • Ring sideroblasts
        • ≥5 iron granules encircling ≥1/3 of the nucleus
        • Usually either many or none
      • Cytoplasmic vacuoles
        • Also seen in copper deficiency
      • Nuclear changes
        • Multinuclearity
        • Nuclear budding, hyperlobulation and satellite nuclei
        • Internuclear bridging
  • Dysgranulopoiesis
    • Peripheral blood and/or bone marrow findings (easier seen in peripheral blood)
      • Hypogranularity
        • Pale cytoplasm almost indistinguishable from background on slide
      • Nuclear hypolobation or irregular hypersegmentation (>5 lobes)
        • Pseudo Pelger-Huet anomaly
          • Two equal size nuclear lobes connected by a thin strand of chromatin
      • Infrequent findings
        • Abnormal cytoplasmic granules (pseudo Chediak-Higashi granules)
          • Giant grey to red granules
        • Dohle bodies
          • Small blue cytoplasmic inclusions
          • Often found at periphery of cell
        • Auer rods
          • Rod-like structures formed by fusion of primary granules
          • May be found in blasts or maturing granulocytes
  • Dysmegakaryopoiesis
    • Peripheral blood platelet abnormalities
      • Giant
        • Larger than a red blood cell
      • Bizarre
        • Irregular shapes and protrusions
      • Hypogranularity
        • Compare to normal platelets with purple granules
    • Bone marrow megakaryocyte abnormalities
      • Micromegakaryocytes
        • Smaller than a promyelocyte
      • Nuclear hypolobation
        • Prominent in 5q- syndrome
        • A single lobe is typically seen in a small megakaryocyte
      • Multinucleation
        • Distinct nuclei without a connecting strand of chromatin
      • Cytoplasmic hypogranularity

Dita Gratzinger MD PhD
Tracy I George MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342

Original posting: 10/23/11

Supplemental studies

Cytogenetic studies should be performed in all cases of myelodysplasia or suspected myelodysplasia

  • FISH for MDS associated abnormalities is not indicated for screening but is helpful if <20 metaphases were examined on karyotyping
  • In the setting of persistent cytopenia in the absence of definitive morphologic features of MDS:
    • The following abnormalities are considered presumptive evidence of MDS
      • Deletions
        • -5, del(5q)
        • -7, del(7q)
        • del(9q)
        • del(11q)
        • del(12p)
        • t(12p)
        • -13, del(13q)
        • i(17q), t(17p)
        • idic(X)(q13)
      • Translocations
        • t(1;3)(p36.3;q21.2)
        • t(2;11)(p21;q23)
        • t(3;21)(q26.2;q22.1)
        • inv(3)(q21q26.2) and t(6;9)(p23;q24)
          • Most frequently present as AML and need to be closely monitored for overt transformation
        • t(11;16)(q23;p13.3)
    • The following are commonly found in MDS but are not by themselves considered definitional for MDS
      • +8
      • -Y
      • del(20q)
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Clinical

International Prognostic Scoring System (IPSS)

Points are assigned based on abnormal findings

Points: 0 0.5 1 1.5 2
BM blast % <5 5-10 - 11-20 21-30
Cytogenetic Group Good Intermediate Poor    
Number of cytopenic lineages 0-1 2-3      
  • Cytogenetic groups
    • Good: Normal, -Y, del(5q), del(20q)
    • Intermediate: All others
    • Poor: Complex, chromosome 7 abnormalities
  • Cytopenias
    • Hemoglobin <10 mg/dl
    • Absolute neutrophil count <1.8 x 103/μL
    • Platelets <100 x 103/μL

Risk groups are determined based on points assigned as above

Risk Group Points Median Survival Evolution to Acute Leukemia
Low 0 5.7 years 9.4 years
Intermediate-1 0.5-1.0 3.5 years 3.3 years
Intermediate-2 1.5-2.0 1.2 years 1.1 years
High >2.5 0.4 years 0.2 years
  • Treatment based on risk group assigned and ability to tolerate therapy including
    • Supportive care
    • Immunosuppressive agents
    • Bone marrow transplantation
    • Intensive cytotoxic treatment
    • Demethylating agents
    • Farnesyl transferase inhibitors

Blood 89:2079, 1997

 

Classification / Lists

WHO 2008 Classification of Myeloid Neoplasms

Myeloproliferative Neoplasms (MPN)

Myeloid and lymphoid neoplasms with eosinophilia and abnormalities of PDGFRA, PDGFRB or FGFR1

Myelodysplastic/Myeloproliferative Neoplasms (MDS/MPN)

Myelodysplastic Syndromes (MDS)

Therapy Related Myeloid Neoplasms

 

Bibliography

  • Swerdlow SH, Campo E, Harris NL, Jaffe ES, Pileri SA, Stein H, Thiele J, Vardiman JW eds. WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues, World Health Organization Classification of Tumours 2008
  • Hofmann WK, Koeffler HP. Myelodysplastic syndrome. Annu Rev Med. 2005;56:1-16.
  • Parker JE, Mufti GJ, Rasool F, Mijovic A, Devereux S, Pagliuca A. The role of apoptosis, proliferation, and the Bcl-2-related proteins in the myelodysplastic syndromes and acute myeloid leukemia secondary to MDS. Blood. 2000 Dec 1;96(12):3932-8.
  • Oriani A, Annaloro C, Soligo D, Pozzoli E, Cortelezzi A, Lambertenghi Deliliers G. Bone marrow histology and CD34 immunostaining in the prognostic evaluation of primary myelodysplastic syndromes. Br J Haematol. 1996 Feb;92(2):360-4.
  • Greenberg P, Cox C, LeBeau MM, Fenaux P, Morel P, Sanz G, Sanz M, Vallespi T, Hamblin T, Oscier D, Ohyashiki K, Toyama K, Aul C, Mufti G, Bennett J. International scoring system for evaluating prognosis in myelodysplastic syndromes. Blood. 1997 Mar 15;89(6):2079-88. Erratum in: Blood 1998 Feb 1;91(3):1100.
  • Verburgh E, Achten R, Maes B, Hagemeijer A, Boogaerts M, De Wolf-Peeters C, Verhoef G. Additional prognostic value of bone marrow histology in patients subclassified according to the International Prognostic Scoring System for myelodysplastic syndromes. J Clin Oncol. 2003 Jan 15;21(2):273-82.
  • Germing U, Gattermann N, Aivado M, Hildebrandt B, Aul C. Two types of acquired idiopathic sideroblastic anaemia (AISA): a time-tested distinction. Br J Haematol. 2000 Mar;108(4):724-8.
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