Acute myeloid dendritic cell leukemia

Acute myeloid dendritic cell leukemia is an exceedingly rare form of leukemia. This form of leukemia represents only about 0.8% of all cases of acute myeloid leukemia. Dendritic cells function as antigen-presenting cells. They process antigen material and present it on the surface to other cells of the immune system. Dendritic cells develop from progenitors in the bone marrow and transform into two subtypes: the myeloid dendritic cell and the plasmacytoid dendritic cell. Leukemic transformation can occur in any of these two cells, but transformation of myeloid dendritic cell is less common and it leads to a form of leukemia known as acute myeloid dendritic cell leukemia.

Molecular findings, cytochemistry, and molecular genetics

The WHO criterion for diagnosis of AML is that myeloid precursors or blasts must represent at least 20% of the cellularity of bone marrow. In the case of acute myeloid dendritic cell leukemia, the blast cells are positive for markers of dendritic cells or monocytes. The markers include CD11c, CD80, CD83, CD86, and major histocompatibility complex class II antigens. The neoplastic dendritic cells are negative for the enzymes myeloperoxidase and esterase. The cells elaborate many cytokines including IL-6 and IL-12.

Clinical findings

Anemia, thrombocytopenia, and blood, marrow, and skin involvement with dendritic-like blast and more mature appearing dendritic cells are characteristic findings. Lymph node and spleen enlargement from leukemic cell infiltration usually is present.

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