1998 Volume 12 Issue 6 Pages 434-438
We report a case of myeloid surface antigen-negative acute myelocytic leukemia (AML). Peroxidase (POX) -positive leukemia was determined by light microscopy to be AML according to French-American-British classification. In general, POX-positive blasts show positive for myeloid surface antigen. In our case, leukemic blasts occupied 88.2% of total nuclear cells in the bone marrow, and 15% of the blasts showed positive for POX staining as defined by both light and electron microscopy. Flow cytometric analysis also revealed the blasts' positivity for myeloperoxidase. Surface antigen analysis of the blasts indicated them to be positive for CD 10, 19, 20, Sm-IgM, Sm-λ, and TdT and negative for myeloid antigens CD 13 and 33. The chromosomal analysis was t (1;19) (q31;p13) in 9 of 20 cells. There were rearrangements at the Ig (H) JH, Cμ, and Ig (L) CL loci. The patient's leukemia is considered to be of a rare type showing POX-positivity but, otherwise manifesting the characteristics of the lymphoid series. Only 5 adult cases of the same phenotype as our case have been reported in the literature. This report represents the first description of a childhood case.
