Clinical: 91 yo male with widespread skin nodules, leukocytosis, and cytopenias. Peripheral blood demonstrated medium-sized blastoid cells with grey-blue cytoplasm, occasional cytoplasmic vacuoles, nucleoli, and some nuclear folds. Flow cytometry of peripheral blood: CD4+/CD56+/CD7+/CD33+/dim CD45+ and CD34-. Skin biopsy demonstrated CD4+/ÇD56+ neoplasm. Diagnosis: Blastic plasmacytoid dendritic cell neoplasm with involvement of peripheral blood. This is a clinically aggressive tumor derived from plasmacytoid dendritic cells with high frequency of cutaneous and bone marrow involvement and leukemic dissemination. This has been previously referred to as : Blastic NK-cell lymphoma, agranular CD4+/CD56+ hematodermic neoplasm, agranular CD4+ NK leukemia