Acute myeloid leukemia with plasmacytoid dendritic cell proliferation: A case report and literature review

Abstract

The present study describes a rare case of plasmacytoid dendritic cell-associated acute myeloid leukemia (pDC-AML). A 70-year-old male patient was diagnosed with pDC-AML and underwent induction chemotherapy using the venetoclax + azacitidine (VA) regimen. After 3 weeks of treatment, bone marrow examination indicated a morphologic leukemia-free state (MLFS); however, the patient experienced persistent cytopenia, which was further complicated by severe pneumonia and gastrointestinal bleeding, both of which improved following treatment. After 3 weeks in MLFS, bone marrow morphology and minimal residual disease analysis revealed a relapse of leukemia. The patient subsequently underwent treatment with selinexor in conjunction with the VA regimen; however, due to severe thrombocytopenia, the family decided to discontinue further treatment. The patient subsequently succumbed shortly after discharge. pDC-AML is an extremely rare disease characterized by low complete remission rates and a poor prognosis. While the VA regimen demonstrates rapid efficacy and favorable safety in elderly patients, especially those unable to tolerate intensive chemotherapy, the risk of relapse remains substantial. CD123-targeted therapies may present potential new therapeutic options for this disease. Improving remission rates and extending survival in patients with pDC-AML remain pressing clinical challenges.

Keywords: acute myeloid leukemia; azacitidine; plasmacytoid dendritic cells; selinexor; venetoclax.

Figure 1.

Morphological analysis and blast proportion changes in bone marrow cells before and after treatment. (A) Morphological examination of bone marrow cells conducted before and after treatment. Magnification, ×1,000; scale bar, 10 µm. (B) Proportion of blasts in peripheral blood before and after treatment. (C) Proportion of blasts in bone marrow before and after treatment.

Figure 2.

Histological examination of bone marrow via H&E and reticulin fiber staining. (A) H&E staining of bone marrow. Magnification, ×40 or ×400; scale bars, 500 or 50 µm. (B) Reticulin fiber staining of bone marrow. Magnification, ×40; scale bar, 50 µm. H&E, hematoxylin and eosin.

Figure 3.

Representative flow cytometry plots showing both the abnormal myeloid blast population and the pDCs. (A) Abnormal myeloid population (CD117part⁺, HLA-DR⁺, CD13⁺, CD33⁺, CD38⁺, CD64⁺, CD34⁻). The green population represents lymphocytes, brown indicates pDCs, red corresponds to myeloid blasts, blue denotes granulocytes, and orange represents monocytes. The brown cell populations in the boxes represent abnormal pDCs. (B) The brown cell populations abnormal pDCs (CD4⁺, CD123⁺, HLA-DR⁺, CD36⁻, CD56⁻, CD11c⁻). Boxed regions were used to highlight representative areas. pDCs, plasmacytoid dendritic cells.

Figure 4.

Analysis of abnormal dendritic cell proportions before and after treatment. (A) Flow cytometry analysis of abnormal plasmacytoid dendritic cells (CD4⁺, CD123⁺, HLA-DR⁺, CD36⁻, CD56⁻ and CD11c⁻) in bone marrow before and after treatment. Only the CD123⁺/HLA-DR⁺ population is presented to highlight the key diagnostic features; other markers, such as CD4⁺, are not presented here. The cell populations in the boxes represent abnormal pDCs. (B) Abnormal pDCs proportions in bone marrow before and after treatment. (C) Morphological analysis of abnormal pDCs in bone marrow. Magnification, ×1,000; scale bar, 10 µm. pDCs, plasmacytoid dendritic cells.

Figure 5.

Timeline of the clinical course. The timeline summarizes the key events in the patient's clinical course, including initial presentation, diagnosis, therapeutic interventions, disease progression and final outcome. AML, acute myeloid leukemia; pDC, plasmacytoid dendritic cell; VA, venetoclax + azacitidine.