Blastic Plasmacytoid Dendritic Cell Neoplasm in the Era of Targeted Therapies

Blastic plasmocytoid dendritic cell neoplasm (BPDCN) is a rare myeloid malignancy, characterized by the involvement of multiple organs, including the skin, bone marrow and blood, lymph nodes and the central nervous system. According to tumor location, the disease is classified as skin-only, systemic-only, and skin and systemic. The cutaneous manifestations of disease are typical and are represented by violaceous single tumors or multiple plaques present in sun-exposed cutaneous areas. BPDCN is issued from the malignant transformation of dendritic cell progenitors and is diagnosed using the classical immunophenotypes CD123, CD4 and CD56 in addition to specific membrane markers of plasmocytoid dendritic cells. BPDCN is an aggressive disease and is associated with a short survival. Upfront therapies involve either chemotherapy regimens in fit patients and CD123-targeted therapies, including interleukin-3 conjugated with diphtheria toxin (Tagraxofusp, SL-401), or Pivekimab sunirine, an anti-IL-3R-drug conjugate, for both fit and unfit patients. Targeted treatments limit the toxicities of chemotherapy and allow the bridging of a consistent proportion of patients to hematopoietic stem cell transplantation, the only treatment associated with potential long-term survival.