Plasmacytoid dendritic cell proliferation and acute myeloid leukemia with minimal differentiation (AML-M0)

What is it about?

The aim of the case report is to deepen the understanding of acute myeloid leukemia with minimal differentiation (AML-M0) complicated with plasmacytoid dendritic cell (pDC) proliferation. A 73-year-old male presented with fever. Bone marrow (BM) aspirates revealed a high percentage of blasts (56.5%) and a notable presence of irregular cells (6.0%), which were characterized by fine reticular chromatin and an abundance of grayish-blue cytoplasm. The BM core biopsy showed hypercellularity (60–90%), with minimal residual hematopoiesis and a significant number of immature mononuclear cells. Flow cytometry identified an abnormal blast population (71.4%) and plasmacytoid dendritic cells (6.1%). The blasts expressed CD117, CD38, CD34 and HLA-DR, while they were negative for myeloperoxidase (MPO) and other myeloid and monocytic markers. The plasmacytoid dendritic cells were positive for CD123, CD4, CD303 and CD304, and negative for CD34, HLA-DR and CD56. Cytogenetic analysis revealed a normal karyotype, and routine screening for fusion genes were negative. However, genomic DNA analysis detected mutations in the ASXL1, RUNX1 (exons 5 and intron 6), FLT3, PHF6 and PTPN11 genes. The patient was diagnosed with acute myeloid leukemia with minimal differentiation accompanied by plasmacytoid dendritic cell proliferation. The accurate diagnosis of acute leukemia with plasmacytoid dendritic cell proliferation requires a multi-disciplinary approach, integrating morphological, immunological, cytogenetic, and molecular biological data, and ruling out blastic plasmacytoid dendritic cell neoplasm (BPDCN). Recognizing and precisely diagnosing these conditions is crucial for determining patient prognosis accurately.

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