Don’t judge a book by its cover – A CD4 negative variant of blastic plasmacytoid dendritic cell neoplasm (BPDCN)

摘要

A 73years old man presented with purpuric lesions of the shoulder,chest and face which had rapidly evolved into violaceous plaques andnodules (Panel A). Biopsy of a forehead lesion revealed a densely cel-lular dermal infiltrate sparing the epidermis. The cells were medium-sized with a blastic appearance (Panel B; Hematoxylin & eosin [H & E]stain, original magnification X10) and immunophenotypically CD3,CD4, CD8, TIA-1, EBER, CD34, TdT, CD117, MPO and CD20 negativeand diffusely positive for CD56 with weak positivity for CD123 (PanelsB(inset)-D; original magnification X10). Immunohistochemistry forTCL1, TCFb, or CD303 was not performed. A diagnosis of a CD4 ne-gative variant of blastic plasmacytoid dendritic cell neoplasm (BPDCN)was rendered. Leukemic and bone marrow involvement were estab-lished later in the patient. Flow cytometry was not performed at thetime of initial diagnosis.