Objective To summarize the diagnostic experiences of blastic plasmacytoid dendritic cell neoplasm (BPDCN) based on the study of its clinicopathological features and immunophenotypes. Methods The clinical data of 2 patients with BPDCN were collected, the structure alteration and cell morphology were observed by HE staining, the immunophenotype of tumor cells were studied by immunohistochemistry staining and flow cytometry was adopted to confirm the bone marrow involvement. Results Two patients, one of whom was a 97 year-old female, presented with cutaneous ecchymosis nodules as the first symptom. The epidermis, but not the dermal, was diffusedly infiltrated by tumor cells, which were medium-sized with irregular nuclei without prominent nucleoli. The other case was a 69 year-old male with lymph node enlargement as the first symptom. The skin was normal, but the lymph nodes were invasively destroyed by tumor cells, which were medium-sized blast-like with prominent nucleoli. The immunophenotypes of the two patients were both positive for CD123, CD4, CD56 and TDT, but negative for B, T lymphocyte derived and myeloid origin markers, both of which involved bone marrow. Conclusions BPDCN is a rare form of hematological neoplasm, skin symptoms or lymph node enlargement may be presented as the initial symptom, the clinical course were highly aggressive with high frequency of bone marrow involvement. The blastic-like lymphoma and leukemia entities should be considered into account for differential diagnose. The precise diagnosis of BPDCN should be established by integrating histomorphology, immunophenotype and clinical presentation information comprehensively.