B-cell prolymphocytic leukemia expressing discordant myeloid-associated antigens in simultaneous specimens from bone marrow and peripheral blood.

The case of a 73-year-old man with B-cell prolymphocytic leukemia (PLL) and rapid clinical demise is reported. Flow cytometric immunophenotyping results of specimens obtained from the patient demonstrated a monoclonal CD5 positive B-cell population with myeloid-associated marker expression, which was discordant: CD15 and CD11b were expressed in bone marrow leukemic cells, whereas peripheral blood leukemic cells showed virtually no expression of these markers. Discordant immunophenotyping results between bone marrow and peripheral blood cells have been reported recently. Additionally, investigators have associated expression of CD13 and CD11b by chronic B-cell lymphoid leukemias with a more aggressive clinical course and shorter survival. Expression of these myeloid-associated antigens by B-cell prolymphocytes in PLL has not been widely reported. Cytogenetic analysis revealed a karyotype of 46,XY/?44,XYdel(1q),del (3p), whereas molecular genetic studies demonstrated immunoglobulin gene rearrangements in both heavy and light chain regions. Cytochemical staining for PAS (periodic acid-Schiff), nonspecific esterase and methyl-green-pyronin was positive in leukemic cells.