CD4+ CD56+ lineage negative malignancies: a new entity developed from malignant early plasmacytoid dendritic cells.

Abstract

The concordant characteristics led us to confirm that this neoplasm actually represents a new entity, that we propose to rename early pDC leukemia/lymphoma. The diagnosis is primarily based on a characteristic immunophenotypic profile i.e. CD4+ CD56+ CD3- CD13- CD33- CD19-. Complementary analyses assessing the expression of more specific pDC-related markers showed the cells to be HLA-DR+, CD123high, CD116low, CD45RA+, BDCA-2+ or BDCA-4+. Such complementary investigations are necessary only in the case of an atypical phenotype, in order to confirm a pDC origin and exclude another hematologic disease. This presently regards the expression of CD33 or cytoplasmic CD3e (cyCD3e) and the negativity of CD56.