NPM1+ /FLT3- Acute Myeloid Leukemia after JAK2-V617F+ Essential Thrombocythemia. Management and Prognosis

Abstract

NPM1+ AML after Essential Thrombocythemia (ET) or Myeloproliferative neoplasms is extremely rare. Only 2 cases have been previously reported after Primary Myelofibrosis. Given the extremely poor prognosis of the Blastic phase of Myeloproliferative neoplasms (MPN-BP), the only curative treatment of these patients is allogeneic stem cell transplantation (allo-SCT) after achieving Complete Response (CR). De novo NPM1+/FLT3- AML is considered a good prognosis entity in which allo-SCT is not contemplated as the first option. A 41 year old diagnosed of ET JAK2 V617F+ 4 years before the diagnosis of AML with normal karyotype and NPM1+/FLT3- was treated with conventional AML induction with Cytarabine and Idarubicine and 3 cycles of high dose Cytarabine. At the diagnosis of AML other 2 mutations were noted: EZH2 and IKZ1. After treatment of AML, NPM1+ clone disappeared, and JAK2 V617F clone reappeared. We opted to treat NPM1+ AML as a de novo AML and we decided to follow up during 2 years without allo-SCT. The patient remains in complete response with NPM1 minimal residual disease negative during the follow up. This case exemplifies the nature of NPM1+ AML secondary to MPD as an extremely sensitive disease to induction therapy plus high dose cytarabine and makes that these type of patients perhaps could be managed without the use of allo-SCT.