A tetraploid minimally differentiated acute myeloblastic leukemia with extensive erythrophagocytosis: a case report and literature review.

Tetraploidy is a rare chromosome number aberration in de novo acute myeloid leukemia (AML), and may be associated with erythrophagocytosis by leukemic blast cells. We report a 48-year-old female patient with minimally differentiated acute myeloblastic leukemia (AML-M0) exhibiting tetraploidy and erythrophagocytosis. The karyotype was 46,XX[2]/92,XXXX[18]. Bone marrow aspirate smears showed large and prominent nuclei, with erythrophagocytosis in leukemic cells. Fluorescence in situ hybridization using RUNX1 dual color break probes detected four fusion signals, accounting for 95 % (190/200), in one interphase nucleus. The mutations of TP53 and the fusion genes RUNX1/ETO, CBFβ/MYH11, and PML/RARα were all negative. This patient showed a poor response to chemotherapy, and died 66 days after the onset. To our knowledge, this is the first reported case of AML-M0 with tetraploidy and erythrophagocytosis and without additional chromosome aberrations. This case of tetraploid AML with poor prognosis suggests that further biological study of more cases of tetraploid AML will be of great importance in improving the understanding and prognosis of this tetraploid AML.