Acute myeloid leukemia with plasmacytoid dendritic cell differentiation initially presenting as skin lesions: A case report.

Plasmacytoid dendritic cell (pDC) accumulations are frequently observed in association with myeloid neoplasms in the bone marrow. We report a case diagnosed as acute myeloid leukemia (AML) with pDC differentiation, which first presented as skin lesions and lymphadenopathies. The skin biopsy revealed pDC-like cells infiltrating the dermal layer. The architecture of the cervical lymph node remained largely preserved, but it was infiltrated by monotonous, atypical cells with a pDC-like immunophenotype in the interfollicular areas. Flow cytometry analysis of the lymph node tissue confirmed the heterogeneity and pDC-like immunophenotype of the tumor cells. Furthermore, a bone marrow biopsy confirmed the presence of underlying AML. DNA sequencing demonstrated that the tumor cells in both the tumor cells in the lymph node and skin biopsy shared the identical genetic abberations as in the bone marrow. Based on these findings, a diagnosis of AML with pDC differentiation was established.