A case of blastic plasmacytoid dendritic cell neoplasm

Abstract

A 51-year-old man presented with multiple, disseminated dark erythematous maculopapules and nodules over the body surface for more than 1 year. Initially, the patient presented with dark erythematous macules on the trunk without discomfort. Then, lesions gradually spread over the whole body surface with the development of tenderness. Physical examination revealed multiple disseminated dark erythematous, well-demarcated maculopapules, infiltrative plaques and subcutaneous nodules on the face, neck, trunk, upper and lower limbs. Some lesions were tender on palpation. An enlarged cherry-like lymph node was detected on the right inguina. Bone marrow inspiration showed that lymphocytes amounted to 32.5%, and naive lymphocytes accounted for 10%. These lymphocytes varied in size with irregular shape, moderate amount of basophilic cytoplasm, irregular nuclei and granular chromatin. Histopathological examination revealed diffuse infiltrate of numerous medium-sized atypical blastic cells with irregular nuclei in superficial dermis and subcutaneous fat tissue. The blastic cells showed sparse fine-granular chromatin, obscure nucleoli and obvious karyokinesis. Immunophenotype examination showed that tumor cells were strongly positive for CD4, CD56 and CD43, weakly positive for CD68 and terminal deoxynucleotidyl transferase, but negative for L26, CD3, CD38, granzyme B and myeloperoxidase. The diagnosis of BPDCN is confirmed based on typical clinical features, histopathology and immunohistology findings. Key words: Lymphoma; Dendritic cells; Stem cells; Plasma cells