Surgical Pathology Criteria

Hypocellular Myelodysplastic Syndrome

Differential Diagnosis

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

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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