Acute myelomonocytic leukaemia
Haematolymphoid Tumours (WHO Classification, 5th ed.)
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editContent Update To WHO 5th Edition Classification Is In Process; Content Below is Based on WHO 4th Edition ClassificationThis page was converted to the new template on 2023-12-07. The original page can be found at HAEM4:Acute Myelomonocytic Leukemia.
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Primary Author(s)*
Fei Yang, MD, FACMG
Oregon Health & Science University, Portland, OR
WHO Classification of Disease
| Structure | Disease |
|---|---|
| Book | Haematolymphoid Tumours (5th ed.) |
| Category | Myeloid proliferations and neoplasms |
| Family | Acute myeloid leukaemia |
| Type | Acute myeloid leukaemia, defined by differentiation |
| Subtype(s) | Acute myelomonocytic leukaemia |
Definition / Description of Disease
Acute myelomonocytic leukemia is an acute leukemia characterized by the proliferation of both neutrophil and monocyte precursors. The peripheral blood or bone marrow has more than 20% blasts (including promonocytes). A minimum of 20% monocytes and their precursors is required for the morphological diagnosis, differentiating this entity from cases of AML with or without maturation that can present with a low-level of monocytes. In the 2016 revision to the World Health Organization (WHO) classification system, acute myelomonocytic leukemia is a distinct entity within the section of HAEM4:Acute Myeloid Leukemia (AML), Not Otherwise Specified[1][2]. This entity does not meet the criteria for inclusion in any of the other AML groups (i.e. AML with Recurrent Genetic Abnormalities, AML with Myelodysplasia-Related Changes, or Therapy-Related Myeloid Neoplasms).
Synonyms / Terminology
French-American-Brirish (FAB) classification M4, NOS
Epidemiology / Prevalence
Approximately 5-10% of AML cases, 3% of childhood leukemia
- occurs in all age groups, but is more common in older individuals.
- median patient age is 50 years
- male-to-female ratio is 1.4:1
Clinical Features
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| Signs and Symptoms | EXAMPLE: Asymptomatic (incidental finding on complete blood counts)
EXAMPLE: B-symptoms (weight loss, fever, night sweats) EXAMPLE: Fatigue EXAMPLE: Lymphadenopathy (uncommon) |
| Laboratory Findings | EXAMPLE: Cytopenias
EXAMPLE: Lymphocytosis (low level) |
editv4:Clinical FeaturesThe content below was from the old template. Please incorporate above.The common clinical presentations are related to anaemia and thrombocytopenia, including fever, pallor, dyspnea, fatigue, loss of weight and bleeding disorders.
Sites of Involvement
Bone marrow
Morphologic Features
- Monoblasts are large cells with abundant cytoplasm, which can be moderately to intensely basophillic, and round nuclei with delicate lacy chromatin and one or more predominant nucleoli; scattered azurophillic granuoles, vacuoles, and Auer rods may be present.
- Promonocytes have a more irregular and delicately convoluted nuclear configuration and cytoplasm which is usually less basophillic and more granulated.
- The peripheral blood typically shows an increase in monocytes, which are often more mature than those in the bone marrow.
Immunophenotype
Cytochemistry
- ≥3% of blasts show myeloperoxidase (MPO) activity.
- Monoblasts, promonocytes and monocytes usually show non-specific esterase activity.
Often a complex immunophenotype with multiple blast populations seen including:
- immature blasts with high CD34 and/or KIT (CD117) expression
- populations with myeloid markers: CD13, CD33, CD15, CD65 and MPO
- populations with monocytic markers: CD4, CD11b, CD11c, CD14, CD64, CD36, CD68 (PGM1), CD163 and lysozyme
- most cases are positive for HLA-DR
- approximately 30% of cases are positive for CD7
| Finding | Marker |
|---|---|
| Positive (universal) | EXAMPLE: CD1 |
| Positive (subset) | EXAMPLE: CD2 |
| Negative (universal) | EXAMPLE: CD3 |
| Negative (subset) | EXAMPLE: CD4 |
Chromosomal Rearrangements (Gene Fusions)
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| Chromosomal Rearrangement | Genes in Fusion (5’ or 3’ Segments) | Pathogenic Derivative | Prevalence | Diagnostic Significance (Yes, No or Unknown) | Prognostic Significance (Yes, No or Unknown) | Therapeutic Significance (Yes, No or Unknown) | Notes |
|---|---|---|---|---|---|---|---|
| EXAMPLE: t(9;22)(q34;q11.2) | EXAMPLE: 3'ABL1 / 5'BCR | EXAMPLE: der(22) | EXAMPLE: 20% (COSMIC)
EXAMPLE: 30% (add reference) |
Yes | No | Yes | EXAMPLE:
The t(9;22) is diagnostic of CML in the appropriate morphology and clinical context (add reference). This fusion is responsive to targeted therapy such as Imatinib (Gleevec) (add reference). |
editv4:Chromosomal Rearrangements (Gene Fusions)The content below was from the old template. Please incorporate above.
- None
- if inv(16)(p13.1q22) or t(16;16)(p13.1;q22) are present, classify as HAEM4:Acute Myeloid Leukemia (AML) with Recurrent Genetic Abnormalities: HAEM5:Acute myeloid leukaemia with CBFB::MYH11 fusion.
Individual Region Genomic Gain / Loss / LOH
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| Chr # | Gain / Loss / Amp / LOH | Minimal Region Genomic Coordinates [Genome Build] | Minimal Region Cytoband | Diagnostic Significance (Yes, No or Unknown) | Prognostic Significance (Yes, No or Unknown) | Therapeutic Significance (Yes, No or Unknown) | Notes |
|---|---|---|---|---|---|---|---|
| EXAMPLE:
7 |
EXAMPLE: Loss | EXAMPLE:
chr7:1- 159,335,973 [hg38] |
EXAMPLE:
chr7 |
Yes | Yes | No | EXAMPLE:
Presence of monosomy 7 (or 7q deletion) is sufficient for a diagnosis of AML with MDS-related changes when there is ≥20% blasts and no prior therapy (add reference). Monosomy 7/7q deletion is associated with a poor prognosis in AML (add reference). |
| EXAMPLE:
8 |
EXAMPLE: Gain | EXAMPLE:
chr8:1-145,138,636 [hg38] |
EXAMPLE:
chr8 |
No | No | No | EXAMPLE:
Common recurrent secondary finding for t(8;21) (add reference). |
editv4:Genomic Gain/Loss/LOHThe content below was from the old template. Please incorporate above.None
Characteristic Chromosomal Patterns
Put your text here (EXAMPLE PATTERNS: hyperdiploid; gain of odd number chromosomes including typically chromosome 1, 3, 5, 7, 11, and 17; co-deletion of 1p and 19q; complex karyotypes without characteristic genetic findings; chromothripsis. Do not delete table.)
| Chromosomal Pattern | Diagnostic Significance (Yes, No or Unknown) | Prognostic Significance (Yes, No or Unknown) | Therapeutic Significance (Yes, No or Unknown) | Notes |
|---|---|---|---|---|
| EXAMPLE:
Co-deletion of 1p and 18q |
Yes | No | No | EXAMPLE:
See chromosomal rearrangements table as this pattern is due to an unbalanced derivative translocation associated with oligodendroglioma (add reference). |
editv4:Characteristic Chromosomal Aberrations / PatternsThe content below was from the old template. Please incorporate above.Myeloid-associated nonspecific cytogenetic abnormalities, such as trisomy 8, are present in most cases.
Gene Mutations (SNV / INDEL)
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| Gene; Genetic Alteration | Presumed Mechanism (Tumor Suppressor Gene [TSG] / Oncogene / Other) | Prevalence (COSMIC / TCGA / Other) | Concomitant Mutations | Mutually Exclusive Mutations | Diagnostic Significance (Yes, No or Unknown) | Prognostic Significance (Yes, No or Unknown) | Therapeutic Significance (Yes, No or Unknown) | Notes |
|---|---|---|---|---|---|---|---|---|
| EXAMPLE: TP53; Variable LOF mutations
EXAMPLE: EGFR; Exon 20 mutations EXAMPLE: BRAF; Activating mutations |
EXAMPLE: TSG | EXAMPLE: 20% (COSMIC)
EXAMPLE: 30% (add Reference) |
EXAMPLE: IDH1 R123H | EXAMPLE: EGFR amplification | EXAMPLE: Excludes hairy cell leukemia (HCL) (add reference).
|
Note: A more extensive list of mutations can be found in cBioportal (https://www.cbioportal.org/), COSMIC (https://cancer.sanger.ac.uk/cosmic), ICGC (https://dcc.icgc.org/) and/or other databases. When applicable, gene-specific pages within the CCGA site directly link to pertinent external content.
editv4:Gene Mutations (SNV/INDEL)The content below was from the old template. Please incorporate above.Acute myelomonocytic leukemia has genetic heterogeneity at the molecular level. Currently there is no specific gene identified that is frequently associated with this subset of AML.
Gene Mutation Oncogene/Tumor Suppressor/Other Presumed Mechanism (LOF/GOF/Other; Driver/Passenger) Prevalence (COSMIC/TCGA/Other) EXAMPLE: TP53 EXAMPLE: R273H EXAMPLE: Tumor Suppressor EXAMPLE: LOF EXAMPLE: 20% Other Mutations
Type Gene/Region/Other Concomitant Mutations EXAMPLE: IDH1 R123H Secondary Mutations EXAMPLE: Trisomy 7 Mutually Exclusive EXAMPLE: EGFR Amplification
Epigenomic Alterations
None
Genes and Main Pathways Involved
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| Gene; Genetic Alteration | Pathway | Pathophysiologic Outcome |
|---|---|---|
| EXAMPLE: BRAF and MAP2K1; Activating mutations | EXAMPLE: MAPK signaling | EXAMPLE: Increased cell growth and proliferation |
| EXAMPLE: CDKN2A; Inactivating mutations | EXAMPLE: Cell cycle regulation | EXAMPLE: Unregulated cell division |
| EXAMPLE: KMT2C and ARID1A; Inactivating mutations | EXAMPLE: Histone modification, chromatin remodeling | EXAMPLE: Abnormal gene expression program |
editv4:Genes and Main Pathways InvolvedThe content below was from the old template. Please incorporate above.None
Genetic Diagnostic Testing Methods
- Conventional chromosome analysis
- FISH myeloid panel
Familial Forms
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Additional Information
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Links
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References
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- ↑ Swerdlow SH, Campo E, Harris NL, Jaffe ES, Pileri SA, Stein H, Thiele J, Arber DA, Hasserjian RP, Le Beau MM, Orazi A, and Siebert R, Editors. World Health Organization Classification of Tumours of Haematopoietic and Lymphoid Tissues, Revised 4th edition. IARC Press: Lyon, France, p159-160.
- ↑ Arber, Daniel A.; et al. (2016). "The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia". Blood. 127 (20): 2391–2405. doi:10.1182/blood-2016-03-643544. ISSN 1528-0020. PMID 27069254.
Notes
*Primary authors will typically be those that initially create and complete the content of a page. If a subsequent user modifies the content and feels the effort put forth is of high enough significance to warrant listing in the authorship section, please contact the CCGA coordinators (contact information provided on the homepage). Additional global feedback or concerns are also welcome. *Citation of this Page: “Acute myelomonocytic leukaemia”. Compendium of Cancer Genome Aberrations (CCGA), Cancer Genomics Consortium (CGC), updated 09/6/2024, https://ccga.io/index.php/HAEM5:Acute_myelomonocytic_leukaemia.