Page 133 - Haematologica Atlas of Hematologic Cytology

CHAPTER 14 - Blastic plasmacytoid dendritic cell neoplasm
Chapter 14. BLASTIC PLASMACYTOID DENDRITIC CELL NEOPLASM
Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare neoplasm, arising from the transformation of the precursors of plasmacytoid dendritic cells, also called professional type I interferon-producing cells or plasmacytoid monocytes. It tends to involve multiple sites, with a predilection for the skin. The diagnosis is fre- quently made on skin biopsy. Bone marrow and peripheral blood involvement with a leukemic picture is also very common. The clinical course is aggressive with a severe prognosis.
Blastic plasmacytoid dendritic cell neoplasm is composed of cells with a lymphoblast-like morphology. They are medium-sized, with round or irregular nuclei, dispersed chromatin, small nucleoli, and abundant agranular cytoplasm. In the peripheral blood and bone marrow samples, many microvacuoles and pseudopod-like expan- sions may be observed. Bone marrow infiltration is often associated with dysplastic alterations of the residual hematopoietic cells. BPDCN cells are negative for esterase and myeloperoxidase reactions (Facchetti et al., 2017).
Diagnosis is based on characteristic immunophenotypic profile of blasts. They express CD4, CD43, CD45RA, CD56, and the plasmacytoid dendritic cell-associated antigens CD123, CD303, TCL1A, CD2AP, SPIB and the type I interferon-dependent molecule MX1, whereas lineage-specific antigens CD3, CD13, CD14, CD16, CD19 and CD20, as well as NK-associated antigens CD94 and CD161, are not expressed. Moreover, T-cell and B-cell receptor genes are germline.
Reference
Facche F, Petrella T, Pileri SA. Blas c plasmacytoid dendri c cell neoplasm. In: Swerdlow SH, Campo E, Harris NL et al (Eds). WHO Classi ca on of Tumours of Hematopoie c and Lymphoid ssues (Revised 4th edi on). IARC: Lyon; 2017. p. 174-177.
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