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| {{SK}} Leukemia, megakaryoblastic, acute; megakaryoblastic leukemia, acute; AMKL | | {{SK}} Leukemia, megakaryoblastic, acute; megakaryoblastic leukemia, acute; AMKL |
| ==Overview==
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| '''Acute megakaryoblastic leukemia''' (AMKL) is a form of [[leukemia]] where a majority of the blasts are [[megakaryoblastic]].<ref name="titleFinal Diagnosis -- Case 439">{{cite web |url=http://path.upmc.edu/cases/case439/dx.html |title=Final Diagnosis -- Case 439 |accessdate=2008-03-08 |format= |work=}}</ref>
| | ==[[Acute megakaryoblastic leukemia overview|Overview]]== |
| | | ==[[Acute megakaryoblastic leukemia classification|Classification]]== |
| It is classified under [[Acute_myelogenous_leukemia#French-American-British_classification|M7]] in the [[French-American-British classification]].<ref name="urlAcute Myeloid Leukemia - Signs and Symptoms">{{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=}}</ref>
| | ==[[Acute megakaryoblastic leukemia pathophysiology |Pathophysiology]]== |
| | | ==[[Acute megakaryoblastic leukemia differential diagnosis|Differentiating Acute megakaryoblastic leukemia from other Diseases]]== |
| In the first three years of life megakaryoblastic leukemia is the most common type of leukemia in patients with Downs syndrome.<ref>Hitzler JK. (2007) Acute megakaryoblastic leukemia in Down syndrome. Pediatr Blood Cancer. Dec;49(7 Suppl):1066-9. PMID: 17943965. </ref>
| | ==[[Acute megakaryoblastic leukemia epidemiology and demographics|Epidemiology and Demographics]]== |
| | | ==[[Acute megakaryoblastic leukemia natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
| ==Pathophysiology== | |
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| It is associated with [[GATA1]], and risks are increased in individuals with [[Down syndrome]].<ref name="pmid12586620">{{cite journal |author=Hitzler JK, Cheung J, Li Y, Scherer SW, Zipursky A |title=GATA1 mutations in transient leukemia and acute megakaryoblastic leukemia of Down syndrome |journal=Blood |volume=101 |issue=11 |pages=4301–4 |year=2003 |pmid=12586620 |doi=10.1182/blood-2003-01-0013 |url=http://www.bloodjournal.org/cgi/pmidlookup?view=long&pmid=12586620}}</ref> However, not all cases are associated with Down syndrome,<ref name="pmid18275433">{{cite journal |author=Hama A, Yagasaki H, Takahashi Y, ''et al'' |title=Acute megakaryoblastic leukaemia (AMKL) in children: a comparison of AMKL with and without Down syndrome |journal=Br. J. Haematol. |volume=140 |issue=5 |pages=552–61 |year=2008 |pmid=18275433 |doi=10.1111/j.1365-2141.2007.06971.x |url=http://dx.doi.org/10.1111/j.1365-2141.2007.06971.x}}</ref> and other genes can also be associated with AMKL.<ref name="pmid17360941">{{cite journal |author=Gu TL, Mercher T, Tyner JW, ''et al'' |title=A novel fusion of RBM6 to CSF1R in acute megakaryoblastic leukemia |journal=Blood |volume=110 |issue=1 |pages=323–33 |year=2007 |pmid=17360941 |doi=10.1182/blood-2006-10-052282 |url=http://www.bloodjournal.org/cgi/pmidlookup?view=long&pmid=17360941}}</ref>
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| This category of AML is associate with 30% or more blasts in the marrow, blast are identified as being of megakaryocyte lineage by; Expression of megakaryocyte specific antigens and platelet peroxidase reaction on electron microscopy.
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| ==Diagnosis== | | ==Diagnosis== |
| | [[Acute megakaryoblastic leukemia history and symptoms|History and Symptoms]] | [[Acute megakaryoblastic leukemia physical examination|Physical Examination]] | [[Acute megakaryoblastic leukemia laboratory findings|Laboratory Findings]] | [[Acute megakaryoblastic leukemia other diagnostic studies|Other Diagnostic Studies]] |
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| *In adults, the features include
| | ==Treatment== |
| **Pancytopenia with low blast counts in the blood
| | [[Acute megakaryoblastic leukemia medical therapy|Medical Therapy]] | [[Acute megakaryoblastic leukemia surgery|Surgery]] | [[Acute megakaryoblastic leukemia cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Acute megakaryoblastic leukemia future or investigational therapies|Future or Investigational Therapies]] |
| **Myelofibrosis
| | ==Case Studies== |
| **An absence of lymphadenopathy and hepatosplenomegaly
| | :[[Acute megakaryoblastic leukemia case study one|Case #1]] |
| **Poor response to chemotherapy,and short clinical course.
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| *In children, the same clinical presentation but with variable course especially in very young children; both leukocytosis and organomegaly may be present in children with M7. Complete remission and long term survival are more common in children than adults.
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| *The morphology of cells was observed by means of Bone marrow smear
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| *The immunophenotype was detected by [[flow cytometry]] and [[immunohistochemistry]] assay.<ref name="pmid17605859">{{cite journal |author=Lei Q, Liu Y, Tang SQ |title=[Childhood acute megakaryoblastic leukemia] |language=Chinese |journal=Zhongguo Shi Yan Xue Ye Xue Za Zhi |volume=15 |issue=3 |pages=528-32 |year=2007 |pmid=17605859 |doi=}}</ref>
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| *In blood and bone marrow smears megakaryoblasts are usually medium sized to large cells with a high nuclear- cytoplasmic ratio. Nuclear [[chromatin]] is dense and homogeneous. There is scanty, variable basophilic cytoplasm which may be vacuolated. An irregular cytoplasmic border is often noted in some of the megakaryoblasts and occasionally projections resembling budding atypical platelets are present. Megakaryoblasts lack [[myeloperoxidase]] activity and stain negatively with sudan black B.
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| *They are alpha naphthyl butyrate esterase negative and manifest variable alpha naphythyl acetate esterase activity usually in scattered clumps or granules in the cytoplasm. PAS staining also varies from negative to focal or granular positivity, to strongly positive staining.
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| *A marrow aspirate is difficult to obtain in many cases because of variable degree of [[myelofibrosis]].
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| *More precise identification by immunophenotyping or with [[electron microscopy]] (EM). [[Immunophenotyping]] using MoAb to megakaryocyte restricted antigen (CD41 and CD61) may be diagnostic.<ref name="pmid12239137">{{cite journal |author=Vardiman JW, Harris NL, Brunning RD |title=The World Health Organization (WHO) classification of the myeloid neoplasms |journal=[[Blood]] |volume=100 |issue=7 |pages=2292-302 |year=2002 |pmid=12239137 |doi=10.1182/blood-2002-04-1199 |url=http://www.bloodjournal.org/cgi/pmidlookup?view=long&pmid=12239137}}</ref>
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| {{Hematological malignancy histology}} | | {{Hematological malignancy histology}} |