Page 134 - Haematologica Atlas of Hematologic Cytology

AB
CD
Figure 1. Blastic plasmacytoid dendritic cell neoplasm. A 66-year-old woman presented with multiple skin le- sions, fatigue and malaise. At physical examination pallor, remarkable hepatomegaly and splenomegaly, and dis- seminated hyperpigmented or bluish subcutaneous nodules involving face, trunk and arms were found. Hema- tologic data were: Hb 10.5 g/dL, WBC 6.56x109/L with 15% blasts, and platelet count 33x109/L. Bone marrow aspirate showed 50% blasts. (A) Buffy coat smear showing medium-sized blasts with dispersed chromatin and abundant agranular cytoplasm. (B) Bone marrow smear. Blast cells have round nuclei or nuclei with irregular outlines and agranular cytoplasm with vacuoles and pseudopod-like expansions. (C) Periodic acid Schiff (PAS) stain reveals coarse blocks of positive material (glycogen) in neoplastic cells. Non-specific and specific esterase as well as myeloperoxidase reactions were negative. (D) Immunocytochemical detection of the plasmacytoid dendritic cell-associated antigen CD123 (IL3-alpha-chain receptor) in many blasts (immuno-alkaline phosphatase technique). Blast cells were also positive for CD4 and CD56, but lineage-specific antigens were not expressed. The diagnosis of blastic plasmacytoid dendritic cell neoplasm suggested by the peculiar clinical, cytological and immunophenotypic features was confirmed by the results of a skin biopsy. This rare neoplasm, arising from the transformation of the precursors of plasmacytoid dendritic cells, tends to involve multiple sites, with a predi- lection for skin. Bone marrow involvement is also very frequent. The clinical course is aggressive with a severe prognosis. The diagnosis is based on a characteristic immunophenotypic profile, i.e. CD4+, CD56+, CD123+, TCL1A+, CD303+, CD3-, CD13-, CD14-, CD16-, CD19-, CD20- and germline T-cell and B-cell receptor genes.
121