Blastic plasmacytoid dendritic cell neoplasm.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare haematological malignancy that originates from the precursors of plasmacytoid dendritic cells. It commonly presents with findings isolated to the skin although it usually progresses to a leukaemic phase. It has a poor prognosis but is curable, particularly in younger patients treated with allogeneic bone marrow transplantation. We report a case of a 79-year old man who had 6 months of progressive, asymptomatic BPDCN manifestations limited to the skin, before developing a leukaemic phase.