DOI: 10.36347/sjmcr.2017.v05i12.003

Pages: 819-822

To discuss biphenotypic leukemia. Mixed phenotype acute leukemia represents a small subset of acute leukemia that cannot be simply assigned as myeloid or lymphoid lineage, because of the ambiguous phenotype the leukemic cells exhibit. It encompasses leukemias containing separate populations of blasts of more than one lineage, or a single population of blasts co-expressing antigens of more than one lineage. The 2008 World Health Organization classification established strict criteria for diagnosis of mixed phenotype acute leukemia, emphasizing myeloperoxidase for myeloid lineage assignment, cytoplasmic CD3 for T lineage assignment, and CD19 and other B markers for B lineage assignment. We report a case of 45 year old female patient presenting with bleeding gums and echymotic patches to medicine emergency with 36% blasts in the peripheral blood film. Gated leukocytes in blast were highly positive for CD19, CD10, CD22, CD13, CD34, CD45, HLADR, TdT and moderately positive for CD33, CD7. Cytochemistry done on bone marrow imprint smears showed MPO positivity. Thus, she was diagnosed as mixed phenotypic leukemia based on cytochemical and flow cytometric findings. Mixed phenotype acute leukemia is associated with poor outcome compared with other types of acute leukemias, particularly in those with Philadelphia chromosome, and clinically presents challenges in diagnosis and treatment. Correct diagnosis requires suspicion and flow cytometric parameters.