Blastic plasmacytoid dendritic cell neoplasm with leukemic manifestation and ETV6 gene rearrangement: A case report.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare malignant tumor of the hemopoietic system that arises from plasmacytoid dendritic cell precursors with a highly aggressive course. BPDCN frequently involves the skin, lymph nodes, peripheral blood and bone marrow. BPDCN is known to develop leukemic dissemination as a feature of myelomonocytic leukemia in the late phase of the disease, which leads to a poorer prognosis. In the present study, a case of BPDCN with leukemic manifestation without cutaneous involvement was reported. In addition, ETS variant gene 6 (ETV6) gene rearrangement was detected in the patient. The patient relapsed soon after complete remisson and had no response to further treatment. To the best of our knowledge, this is the first reported case of BPDCN with ETV6 rearrangement. Following chemotherapy treatment, the patient suffered from severe headache in the complete remission stage; however, brain CT scans showed no significant abnormalities. Several lumbar punctures and intrathecal chemotherapy were performed, and the patient recovered gradually. Therefore, the patient was considered to suffer from central nervous system leukemia. In conclusion, implementation of lumbar punctures and preventive intrathecal chemotherapy are required in BPDCN patients with leukemic manifestation during the remission stage.