Any acute myeloid leukemia that has the chromosomal anomaly FLT3 internal tandem duplication. (A genetic abnormality that arises from duplications of the juxtamembrane portion of the gene and results in constitutive activation of the FLT3 receptor tyrosine kinase protein in early hematopoietic progenitor cells. It is associated with acute myelogenous leukemia where it appears to correlate with a poor prognosis.)