Background: Diagnosis is based on morphological evidence of dysplasia in BMBx Additional studies: karyotyping, flow cytometry, molecular genetics Pearl: Regardless of blast percentage, if a characteristic AML cytogenetic abnormality is seen on BMBx, then should treat as AML. Can be associated with previous drug exposures Example: alkylating chemotherapy or topoisomerase inhibitors Associated with del 5, del 7, or complex chromosomal abnormalities Risk Stratification: Based on