Blastic Plasmacytoid Dendritic Cell Neoplasm without Cutaneous Manifestation: A Case Report

BACKGROUND As an uncommon malignancy with the highest prevalence in the elderly population, blastic plasmacytoid dendritic cell neoplasm or BPDCN is a hematologic disorder with unknown pathogenesis and devastating outcomes. This neoplasm usually manifests in the skin but can also involve the bone marrow, and less frequently the central nervous system (CNS). However, it does not exclude other organs and can even be associated with other malignancies. CASE REPORT Here, we discuss an interesting case of BPDCN in an 85-year-old man who mainly presented with dizziness and weakness. Physical examination revealed splenomegaly, laboratory tests showed pancytopenia, and peripheral blood smear depicted metamyelocytes. Further workup including bone marrow biopsy revealed atypical cells and flow cytometry disclosed 84% blasts positive for cluster of differentiation (CD) 4, CD53, and CD156 suggestive of BPDCN. Moreover, cerebrospinal fluid (CSF) studies came back positive for tumor plasmacytoid dendritic cells. The patient underwent chemotherapy with CHOP, mini-CHOP regimens, and venetoclax, as well as treatment for CNS involvement. He achieved remission, but unfortunately had a recurrence of the disease. Later he was admitted due to pneumonia with concomitant recurrent pulmonary effusions complicated by multiorgan dysfunction and subsequently died. CONCLUSIONS The diagnosis of BPDCN can be very challenging, and high clinical suspicion and intuition are required to reach the diagnosis, especially when patients do not present with cutaneous involvement. Concerning treatment options, novel therapies such as tagraxofusp, a CD123-directed cytotoxin, are emerging in the hope of decreasing the rate of mortality for this aggressive malignancy.