Bone marrow neoplastic

Bone marrow - neoplastic myeloid

Myelodysplastic syndromes (MDS)

MDS with excess blasts

Last author update: 1 August 2011
Last staff update: 11 August 2022

Copyright: 2002-2023,, Inc.

PubMed Search: MDS with excess blasts[TI]

Nikhil Sangle, M.D.
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Cite this page: Sangle N. MDS with excess blasts. website. Accessed March 21st, 2023.
Definition / general
  • Myeloblasts are 5 - 19% of bone marrow differential
  • Usually cytopenias in 2 or 3 lineages
  • Considered high risk MDS
  • Type 1: 5 - 9% blasts in bone marrow or 2 - 4% blasts in peripheral blood, no Auer rods, < 1 billion/L monocytes
  • Type 2: 10 - 19% blasts in bone marrow or 5 - 19% blasts in peripheral blood or Auer rods in any MDS, < 1 billion/L monocytes; more aggressive, greater tendency to progress to AML (Am J Clin Pathol 2005;124:191)
  • Refractory anemia with excess blasts in transformation (RAEB-T): classified as AML under WHO classification
  • Median survival of 16 months for RAEB-1 and 9 months for RAEB-2 (Br J Haematol 2006;132:162)
  • Anemia (normochromic, normocytic or macrocytic), usually neutropenia and thrombocytopenia
Case reports
Microscopic (histologic) description
  • Peripheral blood: nucleated red blood cells, immature granulocytes, neutrophilic hyposegmentation, pseudo-Pelger-Huet cells and hypogranulation, myeloblasts 2 - 4% (RAEB-1) or 5 - 19% (RAEB-2), occasional micromegakaryocytes
  • Bone marrow: normocellular or hypercellular; hyperplasia of granulocytes or erythrocytes; myeloblasts comprise 5 - 9% (RAEB-1) or 10 -19% (RAEB-2) of white blood cells; Auer rods often seen; severe dysplastic changes in all 3 lineages, more severe than other MDS; abnormal localization of immature precursors (ALIP / clusters or aggregates of blasts located away from bone trabeculae and vascular structures); may have increased reticulin fibers
Microscopic (histologic) images

AFIP images

Neutrophil has hypogranular cytoplasm

Hypogranular cytoplasm

Blast in center with adjacent neutrophils

Promyelocytes and myelocytes

Markedly hypogranular cytoplasm

Auer rod present in blast; neutrophils show nuclear hypolobulation

Normocellular biopsy

Normal erythroid precursors

Slightly more cellular marrow

More immature granulocytes

Marked fibrosis with streaming effect

Bone marrow aspirate

Images hosted on other servers:


Various images


Blood, marrow and myocardial infiltration

Molecular / cytogenetics description
Differential diagnosis
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