NPM1 and acute myeloid leukemia: These questions are more stringent when other clinical and biological features classify the AML in the good (e.g., normal leukocyte count, t(8;21), FLT3-ITD negativity and NPM positivity) or standard-risk group (e.g., normal leukocyte count, normal karyotype, FLT3-ITD negativity), as extramedullary localization could be regarded as the only high-risk feature of the disease [3, 4].