AML M4Eo subtype - Immunophenotyping

Author(s): S. Fruehauf, A. Pitkus
Institution(s): Heidelberg University Medical Centre
Last change of this image collection: 2004/08/19

Immunophenotyping: Immunophenotyping was first performed on a fresh peripheral blood specimen. In the forward and side scatter plot area and in the CD45 side scatter plot area are well defined mononuclear cell populations. There are lymphocytoid cells of 32%, increased monocytoid cells of 29% and granulocytoid cells of 37% comprising the total population. In the lymphoblastoid gate, there is a population of 7% B-cells with CD19+ staining and approximately 49% T-cells that are CD2+. The CD4 to CD8 ratio is 1:1. There is also a population of CD34+ cells with coexpression of CD13+ and CD117+, that comprise 4.5% of the cells in the lymphoblastoid gate.

Immunophenotyping was next performed on a fresh bone marrow specimen. In the forward and side scatter areas, there are defined mononuclear cell populations. In the CD45 and side scatter area, there are 22% lymphocytoid cells, 44% monocytoid cells, and 29% granulocytoid cells. In the electronic gate around cell populations with characteristic scattered light properties is a blastoid population with increased forward scatter and low grade expression of CD45 which is lower than that of the lymphocytes. In addition, this gate shows an increase in eosinophilic cells that is integrated into the myeloblastoid population. The myeloid cells consisting of 55% of the total mononuclear cells have the following phenotype: CD34 -, CD11b+, CD13+, CD14+, CD15+ CD33+, HLA DR+, CD117 -, and CD45dim. The blasts lack CD2 expression and the B-cells and T-cells have a decreased antigen expression.



Comment on this image collection: These immunophenotyping findings from this peripheral blood specimen show a myeloid blast population and increased monocytes in the peripheral blood. Differential diagnosis is thought to be an acute myeloid leukemia that has progressed from a chronic myelomonocytic leukemia. It is recommended that immunophenotyping be performed on a bone marrow specimen.
The immunophenotyping performed on the bone marrow specimen is indicative of an acute myeloid leukemia of the M4 Eo subtype without CD2 expression.