A 63-year-old man with a long history of untreated chronic pulmonary disease, a smoker in the past, presented initially with pancytopenia and a clinical diagnosis of myelodysplastic syndrome with excess blasts returned a month later with leukocytosis (WBC 215.9 × 10<sup>6</sup>/μL) and diagnosed with acute myeloid leukemia (AML) with deletion of chromosome 7 and <i>FLT3</i>-TKD mutation. This evidence concerns the gene FLT3 and Pancytopenia.