Primary cutaneous blastic plasmacytoid dendritic cell neoplasm: two case reports

Objective To report two cases of blastic plasmacytoid dendritic cell neoplasm(BPDCN). Methods The clinical and histopathological manifestation, immunophenotype, treatment and prognosis of BPDCN were analyzed in two patients. Results Both of the patients were female with skin lesions as the initial manifestation. Case 1 presented with purple nodules on the waist, back and left upper limb; histopathological examination revealed that a large number of lymphoid cells diffusely infiltrated the dermis and subcutaneous fat layer, with an uninvolved zone separating the infiltrate from the epidermis. Case 2 presented with a subcutaneous mass around the left knee joint, and histopathological examination showed nodular lymphoid infiltrates in the dermis and subcutaneous tissue. Immunohistochemistry showed positive staining for CD4, CD56, CD123(strong)and Ki-67(40%), but negative staining for myeloperoxidase and EBER in both cases, and positive staining for TdT in case 1 but not in case 2. A bone marrow biopsy disclosed active hyperplasia of granulocytic cells, erythroid cells and megakaryocytes, and increased proportion of segmented cells. Immunophenotype analysis revealed that bone marrow was unaffected. Blood routine examination showed anemia in both patients. Patient 1 died two months after the final diagnosis. After chemotherapy with VDLP(vincristine, daunorubicin, L-asparagine and dexamethasone)and CHOP(cyclophosphamide, doxorubicin, vincristine, and prednisolone), skin lesions subsided in patient 2 who also received allogeneic bone marrow transplantation. At the time of this writing, patient 2 was in good condition with no recurrence of skin lesions. Conclusions BPDCN is a rare malignant neoplasm characterized by rapid growth and strong invasion capacity, usually with skin lesions as the initial manifestation. The prognosis of BPDCN is poor and there is no standard treatment. Early diagnosis and timely treatment may improve the prognosis of BPDCN, and allogeneic bone marrow transplantation may markedly extend survival. Key words: Skin neoplasms; Dendritic cells; Stem cells; Treatment outcome; Prognosis