Bone marrow neoplastic

Bone marrow - neoplastic myeloid

Myelodysplastic syndromes / neoplasms (MDS)

MDS with excess blasts

Last author update: 1 August 2011
Last staff update: 22 September 2023

Copyright: 2002-2024,, Inc.

PubMed Search: MDS with excess blasts

Nikhil Sangle, M.D.
Page views in 2023: 2,540
Page views in 2024 to date: 433
Cite this page: Sangle N. MDS with excess blasts. website. Accessed February 26th, 2024.
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

Blast in center with adjacent neutrophils

Promyelocytes and myelocytes

Markedly hypogranular cytoplasm

Auer rod present in blast; neutrophils show nuclear hypolobulation

Bone marrow aspirate

Normocellular biopsy

Normal erythroid precursors

Slightly more cellular marrow

More immature granulocytes

Marked fibrosis with streaming effect

Images hosted on other servers:


Peripheral smear images

AFIP images

Neutrophil has hypogranular cytoplasm

Hypogranular cytoplasm

Images hosted on other servers:


RAEB-2: blood, marrow and myocardial infiltration

Molecular / cytogenetics description
Differential diagnosis
Back to top
Image 01 Image 02