We describe an 84-year-old woman who presented severe pancytopenia and 36.6% of blasts accompanied with erythrophagocytosis in the bone marrow. According to cytochemical and immunological findings, a diagnosis of minimally differentiated acute myeloid leukemia (AML-M0) was established. Cytogenetic analysis revealed del(20)(q11) which were previously reported for one case each of ALL and MDS associated with cytophagocytosis by blasts, leading us to speculate a disease entity. Interestingly, a high expression of mRNA of TNF-alpha was detected by RT-PCR on the bone marrow mononuclear cells.