Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare malignancy derived from plasmacyoid dendritic cells whose biology, clinical features, and treatment options are increasingly better understood.

TCF4 is a master regulator that drives donwstream transcriptional programs in BPDCN. In turn, TCF4 activity is dependent on the bromodomain and extra-terminal domain (BET) protein BRD4 whose inhibition provides a promising therapeutic vulnerability. Notably, TCF4 expression is a highly sensitive marker for BPDCN and augments diagnostic specificity alongside CD4, CD56, CD123, and TCL1. The gene expression profile of BPDCN is characterized by aberrant NF-kappaB pathway activation, while its genomic landscape is dominated by structural chromosomal alterations involving ETV6, MYC, and NR3C1, as well as mutations in epigenetic regulators particularly TET2.

Advances in elucidating the biological characteristics of BPDCN are resulting in a more refined diagnostic approach and are opening novel therapeutic avenues for patients with this disease.