Acute monocytic leukemia: Difference between revisions
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{{Infobox_Disease | | {{Infobox_Disease | | ||
Name = Acute monocytic leukemia | | Name = Acute monocytic leukemia | | ||
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{{CMG}} | {{CMG}} | ||
{{SK}} AMoL; AML-M5 | |||
==Overview== | |||
'''Acute monocytic leukemia''' is considered a type of [[acute myeloid leukemia]]. | |||
==Classification== | |||
A further subclassification (M5a versus M5b) is made depending on whether the monocytic cells are predominantly monoblasts (>80%) ('''acute monoblastic leukemia''') or a mixture of monoblasts and promonocytes (<80% blasts). | |||
==Pathophysiology== | |||
===Genetics=== | |||
M5 is associated with characteristic chromosomal abnormalities, often involving 11q23 or t(9;11)affecting the MLL locus, however the MLL translocation is also found in other AML subtypes. MLL is believed to be prognostically unfavorable in AML-M5 compared to other genetic alterations involving MLL such as t(9;11) The t(8;16) translocation in MLL is associated with hemophagocytosis. | M5 is associated with characteristic chromosomal abnormalities, often involving 11q23 or t(9;11)affecting the MLL locus, however the MLL translocation is also found in other AML subtypes. MLL is believed to be prognostically unfavorable in AML-M5 compared to other genetic alterations involving MLL such as t(9;11) The t(8;16) translocation in MLL is associated with hemophagocytosis. | ||
===Immunology=== | |||
Immunophenotypically, M5-AML variably express myeloid ([[CD13]], [[CD33]]) and monocytic ([[CD11b]], [[CD11c]]) markers. Cells may aberrantly express B cels marker [[CD20]] and the NK marker [[CD56]]. Monoblasts may be positive for [[CD34]]. | |||
==Risk Factors== | |||
AML-M5 is thought to be associated with exposure to epidophyllotoxins. | AML-M5 is thought to be associated with exposure to epidophyllotoxins. | ||
AML-M5 is treated with intensive chemotherapy (such as anthracyclines) or with bone marrow transplantation. | ==Diagnosis== | ||
===Diagnostic Criteria=== | |||
== | In order to fulfill [[World Health Organization]] (WHO) criteria for AML-5, a patient must have greater than 20% blasts in the bone marrow, and of these, greater than 80% must be of the monocytic lineage. | ||
===Laboratory Findings=== | |||
*Peripheral Smear | |||
**[[Monoblasts]] can be distinguished by having a roughly circular nucleus, delicate lacy chromatin, and abundant, often basophilic cytoplasm. These cells may also have pseudopods. By contrast, promonocytes have a more convoluted nucleus, and their cytoplasm may contain metachromatic granules. | |||
*[[Monoblasts]] are typically [[Myeloperoxidase|MPO]] negative and promonocytes are [[Myeloperoxidase|MPO]] variable. Both [[monoblasts]] and promonocytes stain positive for non-specific [[esterase]] (NSE), however [[Esterase|NSE]] may often be negative. | |||
==Treatment== | |||
AML-M5 is treated with intensive chemotherapy (such as anthracyclines) or with [[bone marrow transplantation]]. | |||
==References== | |||
{{reflist|2}} | |||
{{Hematology}} | {{Hematology}} | ||
Revision as of 21:04, 12 September 2012
| Acute monocytic leukemia | |
| ICD-10 | C93.0 |
|---|---|
| ICD-9 | 206.0 |
| MeSH | D007948 |
Template:Search infobox Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Synonyms and keywords: AMoL; AML-M5
Overview
Acute monocytic leukemia is considered a type of acute myeloid leukemia.
Classification
A further subclassification (M5a versus M5b) is made depending on whether the monocytic cells are predominantly monoblasts (>80%) (acute monoblastic leukemia) or a mixture of monoblasts and promonocytes (<80% blasts).
Pathophysiology
Genetics
M5 is associated with characteristic chromosomal abnormalities, often involving 11q23 or t(9;11)affecting the MLL locus, however the MLL translocation is also found in other AML subtypes. MLL is believed to be prognostically unfavorable in AML-M5 compared to other genetic alterations involving MLL such as t(9;11) The t(8;16) translocation in MLL is associated with hemophagocytosis.
Immunology
Immunophenotypically, M5-AML variably express myeloid (CD13, CD33) and monocytic (CD11b, CD11c) markers. Cells may aberrantly express B cels marker CD20 and the NK marker CD56. Monoblasts may be positive for CD34.
Risk Factors
AML-M5 is thought to be associated with exposure to epidophyllotoxins.
Diagnosis
Diagnostic Criteria
In order to fulfill World Health Organization (WHO) criteria for AML-5, a patient must have greater than 20% blasts in the bone marrow, and of these, greater than 80% must be of the monocytic lineage.
Laboratory Findings
- Peripheral Smear
- Monoblasts can be distinguished by having a roughly circular nucleus, delicate lacy chromatin, and abundant, often basophilic cytoplasm. These cells may also have pseudopods. By contrast, promonocytes have a more convoluted nucleus, and their cytoplasm may contain metachromatic granules.
- Monoblasts are typically MPO negative and promonocytes are MPO variable. Both monoblasts and promonocytes stain positive for non-specific esterase (NSE), however NSE may often be negative.
Treatment
AML-M5 is treated with intensive chemotherapy (such as anthracyclines) or with bone marrow transplantation.