In this episode, we explore Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN), a rare and aggressive haematologic malignancy that typically manifests with distinctive skin lesions alongside bone marrow and lymph node involvement. We discuss the diagnostic process, highlighting the essential '123456' immunophenotype (CD123, CD4, CD56) and the high frequency of occult central nervous system disease, which necessitates specific screening. Finally, we review the therapeutic landscape, including the approved CD123-targeted agent tagraxofusp, the use of acute lymphoblastic leukaemia-type chemotherapy regimens, the critical role of stem cell transplantation for durable remission, and promising emerging treatments such as pivekimab sunirine.