Chronic myelogenous leukemia (CML) and mixed phenotype acute leukemia (MPAL) are two distinct entities according to the current WHO classification. However, the distinction can be difficult when adequate clinical history is not available, because both entities could have BCR-ABL1 translocation and B/myeloid biphenotypic blasts. Here we report a 64-year-old man with no previous history of myeloproliferative disorders who presented with marked leukocytosis and 30% circulating blasts. The bone marrow had 39% of blasts and 32% maturing myeloid cells. The blast population showed both B and myeloid differentiation. Cytogenetics revealed the BCR-ABL1 translocation as the sole abnormality. Based on one small-sized case series, many features of our case favored the diagnosis of CML in blast phase with biphenotypic blasts, including: 1) left-shifted granulocytic maturation in peripheral blood; 2) a significant portion of maturing myeloid cells in bone marrow; 3) the diagnostic marrow with higher percentage of BCR-ABL1 harboring cells than that of the blasts; 4) BCR-ABL1 translocation as the sole cytogenetic abnormality; 5) post-induction marrow showed hypercellularity.
Acute leukemia, Biphenotypic blasts, BCR-ABL1
How to Cite
Wang, L. & Xu, X., (2017) “Diagnostic challenge: Acute leukemia with biphenotypic blasts and BCR-ABL1 translocation”, Hematopathology 2(1), p.14-18.