Hematologic findings of acute megakaryoblastic leukemia(M7) were investigated in
seven patients, in whom diagnoses were confirmed by platelet peroxidase activity and
/or monoclonal antiplatelet glycoprotein Ⅱb/ Ⅲa antibody(Jl5).
The findings are summarized as follows ;
1) Peripheral blood findings were as follows ; Hemoglobins were 3.2-12.1g/dL. WBC
counts were 9,000-128,000/cmm and platelet counts were 18,000-562,000/cmm. Giant
platelets were observed in 4 cases, and these patients showed increased number of
mat-using megakaryocytes in bone marrows. Blasts were present in peripheral blood
in all cases, ranging from 9% to 87%.
2) The most conspicuous findings in the morphology of blast cells in peripheral blood
or bone marrow smears was cytoplasmic tagging, Nuclear membrane, nuclear chromatin
pattern, nucleoli and cytoplasmic granuales were variable.
3) Hypercellularity and reticulin fibrosis were seen in all cases of biopsies. Increased
megakaryocytes with polymorphism were observed in 4 out of 7 cases.
4) Cytochemical studies revealed strong localized positivity for acid phosphatase stain.
ANAE and PAS stains were frequently positive with variable patterns. Peroxidase and
Sudan Black B stains showed negative reactions in all cases.
In summary, hematologic findings favoring the diagnosis of M7 are normal to
increased platelet count with presence of giant platelets in peripheral blood, blast
morphology & cytochemical staining charcateristics and reticulin fibrosis of bone marrow
with exess of blasts & atypical maturing megakaryocytes. The features are helpful for
suspecting M7, but the diagnosis should be confirmed by Platelet Peroxidase activity
and/or monoclonal antibody.
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