Flow cytometry study on PB:
A CD45 positive blast population is identified representing about 50% of the total cells analyzed. The blasts are positive for CD33, CD38, HLA-DR, CD13, CD58, CD4, CD123; they are partially positive for CD15 (50%), CD34 (33%), CD14 (30%), lysozyme (33%) and TdT (33%). They are variably positive for CD9 and CD11b. The blasts are negative for MPO, B cell marker and other T cell markers. The findings are consistent with acute myeloid leukemia with monocytic differentiation.
A CD45 positive blast population is identified representing about 50% of the total cells analyzed. The blasts are positive for CD33, CD38, HLA-DR, CD13, CD58, CD4, CD123; they are partially positive for CD15 (50%), CD34 (33%), CD14 (30%), lysozyme (33%) and TdT (33%). They are variably positive for CD9 and CD11b. The blasts are negative for MPO, B cell marker and other T cell markers. The findings are consistent with acute myeloid leukemia with monocytic differentiation.
Cytogenetic findings:
46,XX,t(9;22)(q34;q11.2)[6], 92,slx2[1], 98,sdl,+6,+8,+12,+15,+17,+der(22)t(9;22)[11]; 46XX[2]
FISH: BCR/ABL1 fusion in a total of 81.5% of nuclei.
46,XX,t(9;22)(q34;q11.2)[6], 92,slx2[1], 98,sdl,+6,+8,+12,+15,+17,+der(22)t(9;22)[11]; 46XX[2]
FISH: BCR/ABL1 fusion in a total of 81.5% of nuclei.
Diagnosis: Blast phase CML vs de novo AML with BCR-ABL1
Diagnostic distinction between de novo AML with BCR-ABL1 and blast transformation of CML is difficult without adequate clinical information, and it is controversial for the presence of two distinct entities. The significance of detecting this targetable fusion is felt towarrant a provisional disease category of AML with BCR-ABL1 in 2016 revision of WHO classification. Preliminary data suggest that deletion of antigen receptor genes (IGH, TCR), IKZF1 and/or CDKN2A may support a diagnosis of de novo disease vs BP of CML. NPM1 mutations occur in 25–35% of patients with AML but are absent in patients with CML. Conversely, ABL1 mutations occur in 25% of imatinib-naive patients with CML-BP but are not described in patients with AML. Therapeutic response may help make the distinction. Pt develop chronic phase CML after chemotherapy points to BP CML.
Diagnostic distinction between de novo AML with BCR-ABL1 and blast transformation of CML is difficult without adequate clinical information, and it is controversial for the presence of two distinct entities. The significance of detecting this targetable fusion is felt towarrant a provisional disease category of AML with BCR-ABL1 in 2016 revision of WHO classification. Preliminary data suggest that deletion of antigen receptor genes (IGH, TCR), IKZF1 and/or CDKN2A may support a diagnosis of de novo disease vs BP of CML. NPM1 mutations occur in 25–35% of patients with AML but are absent in patients with CML. Conversely, ABL1 mutations occur in 25% of imatinib-naive patients with CML-BP but are not described in patients with AML. Therapeutic response may help make the distinction. Pt develop chronic phase CML after chemotherapy points to BP CML.