Mature Plasmacytoid Dendritic Cell Proliferation Associated Acute Myeloid Leukaemia: A Case Report and Diagnostic Challenge

Mature plasmacytoid dendritic cell proliferation associated with acute myeloid leukaemia (pDC-AML) is a rare haematologic malignancy marked by clonal proliferation of ≥2% pDCs in bone marrow or peripheral blood. We report a 41-year-old woman with underlying neurofibromatosis who presented with anaemia, persistent fever, and skin lesions. Diagnostic evaluations confirmed pDC-AML based on morphological, immunophenotypic, and genetic findings, including ETV6-PDGFRB fusion. Despite multiple chemotherapy regimens, her disease remained refractory. She ultimately succumbed to febrile neutropenia and pulmonary haemorrhage, with disease progression to over 80% circulating blasts. Differentiating pDC-AML from blastic plasmacytoid dendritic cell neoplasm is crucial due to overlapping morphological features but distinct clinical and immunophenotypic profiles. Accurate diagnosis relies on flow cytometry to highlight the absence of CD56 in pDC-AML. Early recognition and precise characterisation of pDC-AML are essential for optimising management strategies, though prognosis remains poor.