Clinical and biologic features of CD4+CD56+ malignancies

Expression of the plasmacytoid dendritic cell marker BDCA-2 supports a spectrum of maturation among CD4+ CD56+ hematodermic neoplasms

“…These results support the previous findings of BDCA-2 detected by flow cytometry in the leukemic phase of hematodermic neoplasms 8,10,[21][22][23] and by frozen section immunostaining in very small number of cases. 33 Our data suggest a greater degree of heterogeneity of expression in hematodermic neoplasms in tissues.…”

“…CD4 þ CD56 þ hematodermic neoplasms [1][2][3] have been variably referred to as blastic NK-cell lymphomas, 4,5 CD56 þ blastic tumors, 6 CD4 þ CD56 þ lineage-negative malignancies, 7 blastic type 2 dendritic cell leukemia, 8 and plasmacytoid dendritic cell leukemia/lymphoma. 9 CD4 þ CD56 þ hematodermic neoplasms are characterized by presentation as extranodal masses that are often cutaneous, with eventual leukemic dissemination and a clinically aggressive course.…”

“…9 CD4 þ CD56 þ hematodermic neoplasms are characterized by presentation as extranodal masses that are often cutaneous, with eventual leukemic dissemination and a clinically aggressive course. 8 A growing body of phenotypic and functional data argues that they represent the malignant counterparts to plasmacytoid dendritic cells, or their precursors. 2,[7][8][9][10][11] For example, tumors display near-uniform expression of CD4, CD123 and TCL1, HLA-DR and CD45RA which are features of non-neoplastic plasmacytoid dendritic cells at various stages of differentiation.…”

“…8 A growing body of phenotypic and functional data argues that they represent the malignant counterparts to plasmacytoid dendritic cells, or their precursors. 2,[7][8][9][10][11] For example, tumors display near-uniform expression of CD4, CD123 and TCL1, HLA-DR and CD45RA which are features of non-neoplastic plasmacytoid dendritic cells at various stages of differentiation. 12,13 CD4 þ CD56 þ hematodermic neoplasms also fail to express markers of other hematopoietic lineages such as surface or cytoplasmic CD3, CD11b, CD11c, CD13, CD14, myeloperoxidase, lysozyme, CD117, CD19, CD20, CD79a, and CD138.…”

“…20 Several investigators have detected BDCA-2 expression in leukemic CD4 þ CD56 þ hematodermic neoplasms by flow cytometric studies, principally using the mouse monoclonal anti-BDCA-2, clone AC144. 8,10,[21][22][23] BDCA-2 expression in infiltrating CD4 þ CD56 þ hematodermic neoplasms is not well characterized, largely due to lack of appropriate reagents for use in archived tissue sections.…”