CD34 positive dysplastic giant platelets masquerading as blasts on flow cytometry


Giant platelets are commonly seen in myelodysplastic syndrome (MDS), however their immunophenotypic characteristics are not well studied. Here we report a patient with a history of MDS that demonstrated a dysplastic, immunophenotypically abnormal subpopulation of giant platelets. In this patient, flow cytometric analysis of the marrow aspirate showed that 59% of events were with characteristics of CD34 positive blasts, raising the possibility of acute leukemia. However, microscopic examination of the bone marrow aspirate smears showed only 8% blasts and many dysplastic giant platelets. Immunohistochemistry showed CD34 positivity in the patient’s megakaryocytes. Flow cytometric analysis of the patient’s peripheral blood platelets showed that the dysplastic platelets were positive for CD34. This case shows that large dysplastic platelets in MDS may express CD34 and show CD45 staining and side scatter characteristics similar to blasts and can cause a dramatic but spurious increase in the blast count detected by flow cytometry.


Myelodysplastic syndrome, giant platelets, CD34

How to Cite

Abdul-Nabi, A. & Reese, Y. & Treese, S. & Frater, J. L. & Yaseen, N. R., (2016) “CD34 positive dysplastic giant platelets masquerading as blasts on flow cytometry”, Hematopathology 1(2), p.96-101.







Anmaar Abdul-Nabi (Saint Luke’s Hospital, Saint Louis, MO)
Yvette Reese (Barnes Jewish Hospital, Saint Louis, MO)
Susan Treese (Barnes Jewish Hospital, Saint Louis, MO)
John L. Frater (Washington University in Saint Louis)
Nabeel R. Yaseen (Northwestern University)



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Creative Commons Attribution-NonCommercial 4.0

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