Acute monocytic leukaemia
Haematolymphoid Tumours (5th ed.)
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Primary Author(s)*
Fei Yang, MD, FACMG
Oregon Health & Science University, Portland, OR
Cancer Category / Type
Cancer Sub-Classification / Subtype
Acute monoblastic and monocytic leukemia
Definition / Description of Disease
Acute monoblastic and monocytic leukemia are myeloid leukemias in which the peripheral blood or bone marrow has ≥20% blasts (including promonocytes) and in which ≥80% of the leukemic cells are of monocytic lineage (monoblasts, promonocytes and monocytes). Neutrophils may be noted (<20%). In acute monoblastic leukemia, most (≥80%) of the monocytic cells are monoblasts; while in acute monocytic leukemia, most of the monocytic cells are promonocytes or monocytes. In the 2016 revision to the World Health Organization (WHO) classification system, acute monoblastic and monocytic 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
Acute monoblastic leukemia; acute monocytic leukemia; French-American-British (FAB) classification M5, Monoblastic leukemia NOS
Epidemiology / Prevalence
Acute monoblastic leukemia:
- less than 5% of AML cases
- more common in young individuals
Acute monocytic leukemia:
- less than 5% of AML cases
- more common in adults; the median patient age is 49 years
- the male-to-female ratio is 1.8:1
Clinical Features
Put your text here and fill in the table (Instruction: Can include references in the table)
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.
Sites of Involvement
Bone marrow; extramedullary sites such as lymph nodes, skin, gingiva, and CNS.
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 and vacuoles may be present.
- Promonocytes have a more irregular and delicately convoluted nuclear configuration and cytoplasm which is usually less basophillic and more granulated.
- Hemophagocytosis (erythrophagocytosis) may be observed, often associated with t(8;16)(p11.2;p13.3).
- The extramedullary lesion may be composed mainly of monoblasts, promocytes or both.
Immunophenotype
Cytochemistry
- Monoblast granules and monocytes are strongly positive for non-specific esterase and lysozyme in most cases
- Monoblasts are typically negative for myeloperoxidase (MPO), although promonocytes may have scattered positivity.
Often a complex immunophenotype with multiple blast populations including:
- immature blasts with CD34 (30% of cases) and/or KIT (CD117) expression
- populations with myeloid markers: CD13, CD33, CD15, CD65
- populations with at least two monocytic markers: CD4, CD14, CD11b, CD11c, CD64, CD36, CD68, and lysozyme
- most cases are positive for HLA-DR
- MPO can be expressed in acute monocytic leukemia and less often in monoblastic leukemia
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.
Chromosomal Rearrangement Genes in Fusion (5’ or 3’ Segments) Pathogenic Derivative Prevalence t(8;16)(p11.2;p13.3) 5'KAT6A / 3'CREBBP or 5'CREBBP / 3'KAT6A der(8) or der(16) 0.2% of AML
editv4:Clinical Significance (Diagnosis, Prognosis and Therapeutic Implications).Please incorporate this section into the relevant tables found in:
- Chromosomal Rearrangements (Gene Fusions)
- Individual Region Genomic Gain/Loss/LOH
- Characteristic Chromosomal Patterns
- Gene Mutations (SNV/INDEL)
Diagnosis
- The main differential diagnoses of acute monoblastic leukemia include: AML without maturation, AML with minimal differentiation, AML with t(9;11)(p21.3;q23.3), and acute megakaryoblastic leukemia (AMKL)[2]. Extramedullary monoblastic sarcoma needs to be differentiated from malignant lymphoma or soft tissue sarcomas[2].
- The main differential diagnoses of acute monocytic leukemia include: chronic myelomonocytic leukemia, acute myelomonocytic leukemia, and microgranular acute promyelocytic leukamia (APL)[2].
- Haemophagocytosis (erythrophagocytosis) with t(8;16)(p11.2;p13.3) may also occur in acute myelomonocytic leukemia and some cases of AML with maturation[2].
Prognosis
Individual Region Genomic Gain / Loss / LOH
Put your text here and fill in the table (Instructions: Includes aberrations not involving gene fusions. Can include references in the table. Can refer to CGC workgroup tables as linked on the homepage if applicable.)
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). |
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)
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 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.
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 |
Genetic Diagnostic Testing Methods
- Conventional chromosome analysis
- FISH myeloid panel
- FISH or RT-PCR for KAT6A-CREBBP gene rearrangement
Familial Forms
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Additional Information
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Links
http://atlasgeneticsoncology.org/Anomalies/t0816ID1018.html
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, p160-161.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 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.
- ↑ Azoulay, Elie; et al. (2003). "Acute monocytic leukemia presenting as acute respiratory failure". American Journal of Respiratory and Critical Care Medicine. 167 (10): 1329–1333. doi:10.1164/rccm.200206-554OC. ISSN 1073-449X. PMID 12574074.
- ↑ Heim, S.; et al. (1987). "A new specific chromosomal rearrangement, t(8;16) (p11;p13), in acute monocytic leukaemia". British Journal of Haematology. 66 (3): 323–326. doi:10.1111/j.1365-2141.1987.tb06917.x. ISSN 0007-1048. PMID 3476150.
- ↑ Haferlach, T.; et al. (2009). "AML with translocation t(8;16)(p11;p13) demonstrates unique cytomorphological, cytogenetic, molecular and prognostic features". Leukemia. 23 (5): 934–943. doi:10.1038/leu.2008.388. ISSN 1476-5551. PMID 19194466.
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 monocytic leukaemia”. Compendium of Cancer Genome Aberrations (CCGA), Cancer Genomics Consortium (CGC), updated 12/13/2023, https://ccga.io/index.php/HAEM5:Acute_monocytic_leukaemia.