Essential thrombocythemia during treatment of acute myeloid leukemia with JAK2 V617F mutation A case report of a CARE-compliant article

Rationale: The JAK2 V617F mutation is frequently found in ET, while it is rare in de novo AML. ET has a low frequency of leukemic transformation. Both secondary AML (sAML) from ET and AML with JAK2 V617F mutation have poor prognoses. Because of the low incidence of JAK2 mutation in acute myeloid leukemia (AML), the clinical features of AML with JAK2 mutation are rarely reported so far, either transformed from essential thrombocythemia (ET) or de novo AML. Patient concerns: In this article, we present a pediatric AML patient with the JAK2 V617F mutation. Diagnoses: A diagnosis of acute megakaryoblastic leukemia was made and sAML was ruled out. Interventions: The patient underwent chemotherapy. Outcomes: In the first two complete remission periods, we found significantly increased numbers of platelets and bone marrow megakaryocytes, which are characteristic of ET. After the third chemotherapy phase, the disease relapsed; the platelet count was reduced and continued to decrease. When disease relapsed, her family abandoned treatment. Lessons: These observations of our case raise two possibilities: either transient posttreatment thrombocythemia is a feature of AML with JAK2 V617F mutation, or this was a case of secondary AML. Additional information is required to reach better conclusions on the connection between AML and JAK2 mutations.