Transformation from acute promyelocytic leukemia to acute myeloid leukemia with a CEBPA double mutation: A case report and review of the literature.

INTRODUCTION: The transformation of acute promyelocytic leukemia (APL) to acute mononuclear leukemia during treatment is a rare clinical phenomenon, and no CCAAT/enhancer-binding protein alpha (CEBPA) double mutations have been reported. PATIENT CONCERNS: A 42-year-old male was hospitalized for ecchymosis of the left lower limb for more than 1 month, gingival bleeding, and fatigue for 10 days, with aggravation of symptoms for 2 days. DIAGNOSIS: A diagnosis of APL was based on bone marrow (BM) morphology, immunophenotyping, fusion gene analysis, and fluorescence in situ hybridization. At a 1-year follow-up of maintenance treatment, he developed thrombocytopenia and was diagnosed with acute myeloid leukemia (AML) with a CEBPA double mutation by BM morphology, immunotyping, chromosomal analysis, polymerase chain reaction, and next generation sequencing. INTERVENTIONS: Complete remission of APL was achieved after all-trans retinoic acid and arsenic trioxide double induction therapy, followed by 2 cycles of mitoxantrone and cytarabine, and 1 cycle of idarubicin and cytarabine. Thereafter, sequential maintenance therapy of arsenic trioxide + all-trans retinoic acid + methotrexate was started. In the fourth cycle of maintenance therapy, APL was transformed into AML with a CEBPA double mutation. After 1 cycle of idarubicin and cytarabine, the patient achieved complete remission and received 3 cycles of idarubicin and cytarabine and three cycles of high-dose cytarabine as consolidation therapy. OUTCOMES: At present, the patient is in continuous remission with minimal residual disease negative for both of APL and AML. CONCLUSION: AML with a CEBPA double mutation after APL treatment is very rare, thus the prognosis of this event will require further observation.