Blastic Plasmacytoid Dendritic Cell Neoplasm: Updates in Diagnostic and Molecular Pathology.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive form of acute leukemia. BPDCN has a strong predilection for the skin and poses diagnostic challenges with clinical and histologic features that overlap with other conditions. BPDCN shows recurrent myeloid-associated mutations, complex chromosomal aberrancies, and copy-number changes with chromosomal losses involving tumor suppressors and cell cycle regulators. In patients with cutaneous BPDCN, the bone marrow frequently harbors mutationally related myeloid clones/neoplasms; BPDCN transforms from underlying premalignant hematopoietic clones with acquisition of additional progression events, and often occurs in association with ultraviolet damage in sun-exposed sites.