A case of CD4+/CD56+ hematodermic neoplasm (plasmacytoid dendritic cell neoplasm).

CD4+/CD56+ hematodermic neoplasm (blastic plasmacytoid dendritic cell neoplasm) involving the skin is relatively rare and has been of significant interest in the recent literature. We report here a 64-year-old male who presented with multiple purple-red nodules and plaques on his face, back, and chest. Histological examination of skin biopsies showed an intense hematolymphoid infiltration in the dermis and in the subcutaneous tissue. Stains were positive for CD4 (weak), CD56, and terminal deoxynucleotidyl transferase (TdT). These cells were negative for CD2, CD3, CD5, CD10, CD20, CD30, CD68, and T cell intracellular antigen (TIA). In situ hybridization (ISH) for Epstein-Barr virus was negative and the diagnosis was blastic NK cell lymphoma. The patient was treated with a hyper-CVAD regimen (cyclophosphamide, vincristine, doxorubicine, dexamethasone, methotrexate, and cytarabine).This treatment regimen achieved partial remission but the patient died eight months after the diagnosis. The patient presented with exclusively cutaneous involvement at the beginning but progressed rapidly and died shortly after despite aggressive chemotherapy. Due to its rarity, we present here a case of CD4+/CD56+ hematodermic neoplasm.