However, in the last month she stopped responding to therapy and her state of health started declining once again.<h4>Conclusion</h4>Atypical chronic myeloid leukemia (<i>BCR-ABL1 negative</i> with presence of TET2 gene mutation) is an unusual finding in myeloid neoplasms, have unknown prognosis and no current standard of treatment. This evidence concerns the gene TET2 and chronic myelogenous leukemia, BCR-ABL1 positive.