2025 Volume 64 Issue 2 Pages 81-87
Background : Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare tumor derived from the precursors of plasmacytoid dendritic cells, and needs to be differentiated from acute monocytic leukemia (AMoL). Herein, we report the cytomorphological findings in two cases of BPDCN and compare them with those in AMoL.
Cases : Case 1 was a male patient in his 60s who presented with generalized erythema, and Case 2 was a male patient in his 70s who presented with subcutaneous induration in the right hypochondrium. Both patients underwent skin biopsies and lymph node needle biopsies. In both cases, the imprint cytology of lymph node needle biopsies showed tumor cells with pseudopodia. On Giemsa staining, the cytoplasm of the tumor cells was grayish blue in color and contained small vacuoles ; however, the characteristic granules observed in AMoL were not present. Immunohistochemical staining of skin biopsy samples from both patients were positive for CD4, CD56, CD123, TCL1, and CD303 ; on the findings, both cases were diagnosed as having BPDCN.
Conclusions : BPDCN is a closely related neoplasm to AMoL, but treatment strategies for the two diseases are different. It is important to differentiate BPDCN from AMoL based on the findings of pseudopodia and lack of granules on Giemsa staining in the tumor cells in cytology specimens that can be quickly prepared, and to make an early diagnosis by marker search.
