2017 Volume 58 Issue 8 Pages 938-941
A 49-year-old female was initially diagnosed with acute myeloid leukemia (AML) M4 with a CD45+CD13+CD33+CD34−HLA-DR+ immunophenotype. She underwent allogeneic bone marrow transplantation, but the disease recurred. The bone marrow was infiltrated with 87.0% blasts negative for myeloperoxidase (MPO) staining. Immunophenotyping by flow cytometry identified the presence of a CD45-negative blast population. These blasts exhibited a CD13+CD33+CD19−CD10−CD34−HLA-DR− immunophenotype. The lack of CD45 expression is often observed in B-cell acute lymphoblastic leukemia, whereas CD45-negative AML is extremely rare; only one older male with AML-M0 has been reported. In the present case, the CD45-negative blasts had an MPO−CD13+CD33+ phenotype, which is similar to AML-M0.