Leukemia acute
AML not otherwise categorized
Acute monoblastic and acute monocytic leukemia (AML- M5)

Topic Completed: 1 February 2013

Minor changes: 18 November 2019

Revised: 22 January 2019, last major update February 2013

Copyright: (c) 2001-2019, PathologyOutlines.com, Inc.

PubMed Search: Acute monoblastic and acute monocytic leukemia AML M5

Related Topics: Acute monoblastic leukemia (M5a), Acute monocytic leukemia (M5b)

Page views in 2019: 4,912
Page views in 2020 to date: 1,473
Cite this page: Mihova D. Acute monoblastic and acute monocytic leukemia (AML- M5). PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/leukemiaacutemonocyticleukemia.html. Accessed May 24th, 2020.
Definition / general
  • 80% or more nonerythroid bone marrow cells are monocyte lineage (monoblasts, promonocytes and monocytes)
  • A minor neutrophil component < 20%
Microscopic (histologic) images

Images hosted on other servers:
Missing Image

Erythrophagocytosis in AML
M4 / M5 (see cell in upper right)

Enzyme cytochemistry
  • Monoblast granules and monocytes are strongly positive for nonspecific esterase and lysozyme, but negative for myeloperoxidase
  • More mature monocyte lineage cells may be weakly myeloperoxidase positive
  • Note: if NSE negative, confirm monocyte lineage with immunostains
Positive stains
Molecular / cytogenetics description
  • 11q23 translocations in 19%, trisomy 8 in 17%
Back to top