Secondary chronic myeloid leukemia following acute myeloid leukemia treated with autologous hematopoietic stem cell transplantation: a case report

Acute myeloid leukemia (AML) is a hematopoietic stem cell malignancy and the most common type of leukemia, with the 5-year relative survival rate of 19% in Europe. Chronic myeloid leukemia (CML) is a slowly progressive clonal malignant disease, and a myeloproliferative disorder which is derived from biphasic hematopoietic stem cells but driven by progenitor cells. AML following CML is common, which can be caused by an antecedent myeloid malignancy, leukemogenic therapy, or without an identifiable prodrome or exposure to cytotoxic agents. However, the case of secondary chronic myeloid leukemia following acute myeloid leukemia treated with autologous hematopoietic stem cell transplantation is rare.Here we report a unique case of secondary CML after AML treated by chemotherapy and autologous peripheral blood stem cell transplantation. The 34-year-old male was diagnosed with AML subtype M5b according to clinical features in 2011. The patient was treated with the MAE program (mitoxantrone, cytosine arabinoside, etoposide) for two courses, followed by the IAE program (idarubicin, cytosine arabinoside, etoposide) and cytosine arabinoside for consolidation chemotherapy. An autologous hematopoietic stem cell transplantation with prophylactic intrathecal methotrexate cytarabine and dexamethasone was initiated.Subsequently, the patient achieved complete remission in 2012. After 4 years, the patient presented with leukocyte elevation of more than 4 months, and then was diagnosed with secondary CML. Based on this diagnosis, and with respect to the patient's severely compromised overall condition, tyrosine kinase inhibitors (TKI) therapy was conducted in 2016. The patient achieved, and continue to be in, complete remission.The case expands the understanding of secondary CML and emphasizes the importance of oncological vigilance in patients with secondary CML after AML therapy.