The coexistence of acute myeloblastic leukemia and diffuse histiocytic lymphoma in the same patient as demonstrated by multiparameter analysis.

Measurement of cellular DNA content by flow cytometry demonstrated presence of two distinct aneuploid neoplasms in a patient who developed acute myeloblastic leukemia (AML) 4 mo after diagnosis of a diffuse histiocytic lymphoma (DHL). A lymph node aspirate contained peroxidase-negative, "null," hyperdiploid (2.6C) DHL cells, while the bone marrow (BM) contained 84% primitive peroxidase-positive tetraploid AML cells (4.0C). Minor populations of hyperdiploid HDL and normal diploid cells could be detected by flow-cytometry in the BM, and all three populations were also seen in the peripheral blood.