Abstract: Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare, aggressive hematopoietic malignancy. This paper reports a case of BPDCN. A 58-year-old male presented with erythematous patches, plaques, and nodules for 10 months, aggravated 1 month. Dermatological examination revealed multiple confluent dark purplish-red patches, nodules, and masses on the face, trunk, and extremities, with significant infiltration and a firm texture upon palpation. Pathology and immunohistochemistry suggested BPDCN. The patient experienced significant regression of skin lesions after receiving a combination chemotherapy of CHOP and chidamide. Bone marrow smears and flow cytometry were consistent with BPDCN, and bone marrow biopsy showed a lymphohematopoietic system tumor. Whole-body PET/CT scan indicated slightly enlarged lymph nodes in multiple regions with increased sugar metabolism, particularly in the bilateral inguinal and axillary areas, with no splenomegaly, but with diffuse uniform metabolism slightly higher than liver levels.

Key words: blastic plasmacytoid dendritic cell neoplasm (BPDCN), CHOP, chidamide