by andywalsh | March 8, 2019 12:26 am
It is defined as a disorder in which there is a formation of blats which are known as the mega karyoblastic. It is also known as the AMKL. It is classified as M7 in the French American British classification. It is a form of leukemia. It is associated with the one third of the blasts in the marrow and these are identified by the mega karyocyte lineage and the expression of mega karyocyte specific antigens and platelet peroxidase reaction in the electron microscopy.
It includes the pan cytopenia in adults with a low blast cell count in the blood. There is myelo fibrosis along with the absence of lymph adenopathy and hepato splenomegaly. There is a poor response to the chemotherapy and have a short clinical course. In the children the clinical presentation is same but the the course is variable mainly in the young children. The children with M7 have a leucocytosis and organomegaly. A complete remission and long term survival is common among the children as compared to the adults. During the first three years of life this is the most common type of leukemia with the Down syndrome.
It is associated with the GATAI and increased risk is associated with the Down syndrome. There are few genes which are associated with the Down syndrome and other are associated with the AMKL. The other gene which is related is the MKL1 which is also referred as MAL. It is a co factor of serum response factor.
The morphology of the cell is mainly seen by the smear of bone marrow. The flow cytometry and immune histochemistry help to know about the immune phenotype. The blood and bone marrow smears with mega karyoblasts show medium to large size cells which have a high nucleo cytoplasmic ratio. The nuclear chromatin is dense and homogenous. The cytoplasm is scanty, variable and basophilic in nature. It can be vacuolated. In some of the mega karyoblasts one can notice irregular cytoplasmic borders.
One may also see projections which resembles budding atypical platelets. The mega karyo blasts have no myelo peroxidase and stain negatively with the Sudan black B. They are negative to the alpha napthyl butyrate esterase. They have a variable alpha napthyl butyrate esterase activity and is present in the form of scattered clumps or granules in the cytoplasm.
The PAS staining also varies and is from negative to focal positive. It can be strongly positive also. It is difficult to obtain a marrow aspirate and is due to the variable degree of myelo fibrosis. A more precise identification by the immune pheno typing or with the help of electron microscope. The immune pheno typingalong wih the MoAb to mega karyocyte restricted antigen which can be diagnostic.
It depends on the cause. 33 percent of the cases are associated with the t mutation in children. They have a poor prognosis. 33 percent of the cases are associated with the Down syndrome. They have a fair prognosis. 33 percent of the cases are associated with the heterogeneous and have a poor prognosis.
There is no definite treatment for this disorder.
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Source URL: https://alldiseases.org/acute-megakaryoblastic-leukemia/
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