Figure 1.

Representative morphologies of BPDCN in blood or bone marrow aspirates. (A-D) Typical morphology with large pseudopodia, microvacuoles in some blasts, an eccentrically located nucleus, and heterogeneous coloration of the cytoplasm (lightly basophile with some gray areas). The nuclei are sometimes prominent (C). (E) Lymphoid-like morphology with small cells, very small cytoplasm, and mature chromatin of the nucleus. In this case, other cells (arrows) are bigger and present a more immature profile. (F-G) Monoblast-like blasts. Cells are bigger and more basophilic, with irregular nuclei and prominent nucleoli. Case G is BPDCN secondary to acute transformation of CMML. (H) A more immature morphology with a high nucleocytoplasmic ratio, diffuse chromatin, nucleoli, and basophilic cytoplasm. (I-J) Presence of granules in the cytoplasm (arrows). (K) Atypical big and round vacuoles in the cytoplasm. May-Grünwald-Giemsa, original magnification ×1000.