Specific cutaneous involvement of a mixed-type mature plasmacytoid dendritic cell tumor in chronic myelomonocytic leukemia

Abstract

A 68-year-old man with chronic myelomonocytic leukemia (CMML), proven by bone marrow biopsy, presented to our clinic with pruritic indurated papules on his scalp, trunk and gluteal regions that have been present for two years. Purpuric, infiltrated miliary papules and petechiae were predominantly observed on his trunk, abdomen, back and legs. Histopathological examination revealed atypical monocytic cells with convoluted, irregularly shaped chromatin accompanied by histiocytes. He was finally diagnosed with CMML with specific cutaneous involvement of mixed-type mature plasmacytoid dendritic cell tumor. Immunohistochemical tests showed positive CD4, CD56, and CD123 mature plasmacytoid dendritic cells, positive CD1a indeterminate dendritic cells, and positive CD68 monocytic cells.