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تسجيل

Blastic Plasmacytoid Dendritic Cell Neoplasm: Histopathology

المؤلف:  Hoffman, R., Benz, E. J., Silberstein, L. E., Heslop, H., Weitz, J., & Salama, M. E.

المصدر:  Hematology : Basic Principles and Practice

الجزء والصفحة:  8th E , P1030

2026-11-10

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Skin biopsy reveals a dense monomorphous infiltrate in the dermis and subcutis of blastoid cells (Fig. 1). The epidermis is typically spared and there is usually a clear “grenz zone,” an uninvolved strip of papillary dermis just below the epidermis. The individual tumor cells are medium to large sized with scant cytoplasm and have similar appearance in skin, marrow, lymph nodes, blood, and other involved sites. Some have a plasmacytoid appearance with eccentric nuclei, cytoplasmic vacuolation, and/or extended cytoplasmic projections similar to “hand-mirror” cells that are seen in acute lymphoblastic leukemia. Mitotic figures are often present.

The classic immunophenotype of BPDCN cells is positivity for CD123 (IL-3 receptor α chain), CD4, and CD56, on CD45-positive cells indicating hematopoietic origin. The cells fall in the CD45 dim, side-scatter low “blast gate” on flow cytometry. Staining for the protooncogene T-cell leukemia/lymphoma protein 1 A (TCL-1) is often positive, although this marker is not specific for BPDCN and can also be expressed in several lymphoid malignancies. Terminal deoxynucleotidyl transferase (TdT) is positive in approximately one-third of cases. The pDC antigen CD303 (BDCA-2) is lost in some BPDCNs, but when positive, its expression supports the diagnosis. CD4 or CD56 may be negative in a minority (approximately 8%) of cases. One diagnostic schema suggests that BPDCN is likely if the tumor cells express at least 4 of 5 markers among CD123, CD4, CD56, TCL-1, and CD303.13 CD34 is usually negative. Myeloperoxidase and lysozyme are negative in BPDCN and when either is positive makes AML more likely.

Fig1. BLASTIC PLASMACYTOID DENDRITIC CELL NEOPLASM (BPDCN) SKIN LESION, SKIN BIOPSY PHOTOMICROGRAPHS, AND IMMUNOHISTOCHEMISTRY (AT 20× MAGNIFI CATION) FOR CD123, CD4, AND CD56.