<h4>Background</h4>Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive hematologic malignancy characterized by neoplastic cells that are positive for CD123, CD4, BDCA2, and TCL1 and aberrant expression of CD56. This evidence concerns the gene NCAM1 and CD4+/CD56+ hematodermic neoplasm.