Surgical Pathology Criteria

Refractory Cytopenia with Multilineage Dysplasia (RCMD)

Differential Diagnosis

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)


Hairy Cell Leukemia Aplastic Anemia Hypocellular (Hypoplastic) MDS Hypocellular AML
Variable cellularity Low cellularity Low cellularity Low cellularity
No dysplasia Mild erythroid dyspoiesis allowed but no ring sideroblasts Dysplasia present Variable dysplasia
Marrow blasts <5% Marrow blasts ≤1%, no ALIP Marrow blasts <20%, ALIP Marrow blasts ≥20%
Blood blasts rare No blood blasts Blood blastsl <20% Blood blasts ≥20%
Cytogenetics nonspecific May have cytogenetic abnormalities May have defining abnormalities May have defining abnormalities
Clonal B cells No B cell clone No B cell clone No B cell clone
ALIP = abnormal localization of immature precursors


Primary Myelofibrosis, Fibrotic Phase MDS with Fibrosis Post-Polycythemia Vera Myelofibrosis
JAK2V617F mutations in 50% JAK2V617F mutations rare JAK2V617F mutations in almost 100%
Tightly clustered hyperchromatic megakaryocytes Increased but non-clustered dysplastic megakaryocytes Variable size and increase in megakaryocytes
Prominent splenomegaly Rare splenomegaly Prominent splenomegaly
Does not meet criteria for MDS or PV Commonly multilineage dysplasia and increased blasts History of polycythemia vera
Myelofibrosis grade 2-3 and cytogenetic abnormalities are common in all three

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