Near-tetraploid minimally differentiated acute myeloid leukemia with extensive erythrophagocytosis by leukemic blasts.

Numerical change of chromosomes is common in acute myeloid leukemia (AML). However, a chromosome number as high as near-tetraploidy is very rare, especially in minimally differentiated AML (AML-M0). Erythrophagocytosis by reactive or malignant histiocytes is common in malignant hematological diseases; however, erythrophagocytosis by leukemic blasts is also very rare, especially in AML-M0. We report here the first case of AML-M0 with both of these unique characteristics: a near-tetraploid karyotype and erythrophagocytosis by leukemic blasts.