CD33 and acute promyelocytic leukemia: Although there were no traditional Auer rods identified, the suspicion for acute promyelocytic leukemia (APL) was raised following flow cytometric studies that showed a large aberrant myeloid population (65.3% of total events) of CD13+/CD33+/CD34−/CD64+/CD117+/CD123+/HLA‐DR− cells consistent with an APL immunophenotype.