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Acute monoblastic leukemia (AMoL) is characterized by cells with highly undifferentiated morphology. Cytochemistry with non-specific esterases is negative in up to 20% of cases. Immunophenotyping by flow cytometry has an essential role in diagnosing such a subtype of leukemia and a multiparametric approach with a wide monoclonal antibody panel is necessary. We describe a case of AMoL with morphology resembling either plasma blasts or very immature erythroblasts. Diagnosis was made by alpha-naphtyl-acetate esterase staining and with immunophenotyping, which was made with a wide monoclonal antibody panel. Blasts were positive for monocytic markers. Most of leukemic cells, however, were positive for Glycophorin-A. The presence of Glycophorin-A, which is considered as a specific marker of the erythroid lineage, has never been reported previously in cases of AMoL. This peculiar immunophenotype might be interpreted as deriving from a common myelo-erythroid precursor undergone leukemic transformation. [ABSTRACT FROM AUTHOR]

We report a case of de novo diffuse large B-cell lymphoma (DLBCL) in leukemic phase, positive for both CD5 and CD13. Morphologic evaluation, flow cytometric immunophenotyping, karyotyping and polymerase chain reaction studies were performed. Neoplastic lymphocytes appeared as blast-like cells, positive for CD19, CD20, CD5, CD13, CD79a, HLADR, and with restriction for surface immunoglobulin K light chains. Rearrangement of IgH gene, BCL2/IgH translocation and complex karyotype were found. The patient was treated with RCOMP regimen and achieved complete remission. However, only one month after the first restaging of disease, the patient presented with symptoms attributable to central nervous system involvement and her clinical conditions worsened rapidly. While both CD5 expression and leukemic presentation are uncommon findings in DLBCL, positivity for CD13 is very rare. The outcome of our patient shows the poor prognosis of CD5+ DLBCL with leukemic presentation. The possible role of CD13 coexpression is discussed. [ABSTRACT FROM AUTHOR]

Hematogones are precursors of B-lymphocytes detected in small numbers in the bone marrow. Flow cytometry is the most useful tool to identify hematogones and, so far, 4-color methods have been published. In addition, flow cytometry is used in the diagnosis and followup of lymphomas. We developed a flow cytometric 7-color method to enumerate hematogones and to assess B-lymphocyte clonality for routine purposes. We evaluated 171 cases of Bcell non-Hodgkin lymphomas, either at diagnosis or in the course of follow-up. By our diagnostic method, which was carried out by the combination K/γ/CD20/CD19/CD10/CD45/CD5, we were able to detect hematogones in 97.6% of samples and to distinguish normal B-lymphocytes, neoplastic lymphocytes and hematogones in a single step. The percentage of hematogones showed a significant inverse correlation with the degree of neoplastic infiltration and, when bone marrow samples not involved by disease were taken into consideration, resulted higher in patients during followup than in patients evaluated at diagnosis. [ABSTRACT FROM AUTHOR]