Blastic plasmacytoid dendritic cell
neoplasm is a rare but clinically aggressive
tumor known to be derived from the precursors of plasmacytoid dendritic cells with frequent cutaneous involvement. Though the majority of patients initially respond to multi-agent
chemotherapy, most cases without hemopoietic
stem cell transplantation relapse within a year. We describe a case of a 71-year-old man with a dark-purple subcutaneous nodule (5×3 cm) under his right auricle. Histologic examination of the excisional biopsy specimen revealed a diffuse proliferation of blast cells with irregular nuclei, fine
chromatin and one to several small nucleoli in the dermis extending to the subcutaneous soft tissues. The
tumor cells expressed CD123, CD56, CD4, CD7, LCA, and TdT but not CD3, CD20, CD79a, CD10, CD68, CD163,
myeloperoxidase (MPO), or
naphthol-ASD-
chloroacetate (ASD-Ch)
esterase. A diagnosis of blastic plasmacytoid dendritic cell
neoplasm was made. He did not have any other lesions except for the solitary skin nodule. He had refractory
cytopenia with multilineage dysplasia (RCMD) and renal dysfunction. It was difficult for him to receive hemopoietic
stem cell transplantation because of his advanced age and renal dysfunction. We had previously experienced successful treatment with ABVD
chemotherapy for
interdigitating dendritic cell sarcoma after ineffective CHOP
chemotherapy. The plasmacytoid dendritic cell is one of the precursor cells of the interdigitating dendritic cell. Therefore we tried to apply ABVD
therapy to him. The first course of ABVD induced complete remission. Although the
therapies were reduced and postponed because of various complications, he is now
in complete remission that has lasted for 21 months. Although previously not reported, ABVD
therapy is useful for patients with blastic plasmacytoid dendritic cell
neoplasm who cannot receive hemopoietic
stem cell transplantation.