Acute monocytic leukemia

Infobox_Disease
Name = Acute monocytic leukemia


Caption =
DiseasesDB =
ICD10 = ICD10|C|93|0|c|81
ICD9 = ICD9|206.0
ICDO =
OMIM =
MedlinePlus =
eMedicineSubj =
eMedicineTopic =
MeshID = D007948

Acute monocytic leukemia (AMoL, or AML-M5)cite web |url=http://www.ucsfhealth.org/adult/medical_services/cancer/leukemia/conditions/aml/signs.html |title=Acute Myeloid Leukemia - Signs and Symptoms |format= |work=] is considered a type of acute myeloid leukemia.

Diagnosis

In order to fulfill World Health Organization (WHO) criteria for AML-5, a patient must have greater than 20% blasts in the marrow, and of these, greater than 80% must be of the monocytic lineage. 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). 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.

Immunophenotypically, M5-AML variably express myeloid (CD13, CD33) and monocytic (CD11b, CD11c) markers. Cells may aberrantly express B-cell marker CD20 and the NK marker CD56. Monoblasts may be positive for CD34.

Causes

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.

AML-M5 is thoughtby whom to be associated with exposure to epidophyllotoxins.

Treatment

AML-M5 is treated with intensive chemotherapy (such as anthracyclines) or with bone marrow transplantation.

References

External links

* [http://pathy.med.nagoya-u.ac.jp/atlas/doc/node47.html Images] at Nagoya University
* [http://www.hmds.org.uk/insets/m5.htm Image] at hmds.org.uk
* [http://www.med-ed.virginia.edu/courses/path/innes/wcd/myeloid1.cfm Histology] at University of Virginia
* [http://www.academic.marist.edu/~jzmz/topics/erythroleukemia/myelomono1.html Overview] at Marist College