A 58-year-old Japanese man, who had been followed up and received blood transfusions regularly for myelodysplastic syndrome (refractory anemia with an excess of blast cells) for 1 year, developed acute myeloid leukemia. He had pancytopenia, with a white blood cell (WBC) count of 800 cells/μL (to convert to × 109/L, multiply by 0.001), neutropenia (7.0 % of WBCs), and increased circulating blast cell count (58% of WBCs). He had received fluconazole as antifungal prophylaxis.