Surgical Pathology Criteria

Refractory Anemia with Excess Blasts (RAEB)

Differential Diagnosis

Refractory Anemia with Excess Blasts Acute Myelogenous Leukemia
Blasts <20% in both peripheral blood and bone marrow Blasts frequently ≥20% in peripheral blood and/or bone marrow
AML defining translocations not present May have AML defining translocations t(8;21)(q22;q22) or inv or t(16)(p13.1;q22)

Non-neoplastic disorders may simulate myelodysplasia

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)

 

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