Mehdi Montazer - Department of Hematopathology, Molecular Pathology and Cytogenetics, Shiraz University of Medical Sciences, Shiraz, Iran
Freidoon Solhjoo - Department of Hematopathology, Molecular Pathology and Cytogenetics, Shiraz University of Medical Sciences, Shiraz, Iran
Maral Mokhtari - Department of Hematopathology, Molecular Pathology and Cytogenetics, Shiraz University of Medical Sciences, Shiraz, Iran
Ahmad Monabati - Department of Hematopathology, Molecular Pathology and Cytogenetics, Shiraz University of Medical Sciences, Shiraz, Iran

Introduction: Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematodermic myeloid malignancy, with both cutaneous and hematopoietic involvement, which had been known as blastic natural killer cell leukemia/lymphoma in the past. However, it is now known to be derived from the recently recognized subtype of dendritic cells named plasmacytoid dendritic cells. To our knowledge, this is the first report from Iran. Case presentation: Herein, we present three cases of BPDCN diagnosed in the pasttwo years and discuss the different available diagnostic modalities including flow cytometry, immunohistochemistry and cytogenetics. BPDCN shares significant mmunophenotypic characteristics with T/NK cell lymphoma/leukemia and the dual reactivity for CD4 and CD56 in BPDCN cannot sufficiently distinguish these two entities. At the point, more specific markers for BPDCN, such as CD123, are essentially helpful in this differentiation. Lineage-specific markers were negative, including myeloid (CD13, CD33, CD117, MPO), monocytic (CD11b, CD14, CD64), megakaryocytic (CD61), B-cell (CD19, CD10, CD20) and T-cell (CD3) antigens. BPDCN is a diagnosis of suspicion and can be easily missed approaching the patients with acute leukemia. This is also true while dealing with cutaneous hematopoietic infiltrates where a correct diagnosis of BPDCN is essentially important because of the high probability of future bone marrow dissemination. Discussion: Overall, we believe that BPDCN is a rare diagnosis that should not bemissed. Currently available immunohistochemical and flow cytometric markers are of great aid, but the main key to solve the problem of BPDCN is clinicopathologic suspicion.

Leukemia, Blastic plasmacytoid dendritic cell neoplasm, Immunophenotyping, Iran