Cytophagocytosis by the blast cells in acute myeloid leukemia.

The occurrence of cytophagocytosis as spontaneous ingestion of cells by blast cells has been poorly investigated in acute leukemia. Cytophagocytosis by blasts in acute myeloid leukemia (AML) was observed in eleven patients who represent 1% of AML cases seen in our institution (one M1, two M2, four M4 and four M5). Prominent features of cytophagocytosis by AML blasts are particularly evident in leukemias involving monocytic cells and were more obvious in the bone marrow than the peripheral blood. AML of the monocytic type with cytophagocytosis are frequently associated with cytogenetic aberrations involving chromosomes 8 and 16. Finally the poor outcome of AML patients with cytophagocytosis and their poor response to therapy and short survival is stressed.