Essential Thrombocythemia in a Nonagenarian Presenting With Acute Myocardial Infarction.

Essential thrombocythemia (ET) is a chronic Philadelphia-negative myeloproliferative neoplasm (MPN) characterized by clonal thrombocytosis and an increased risk of arterial and venous thrombosis. Because ET has a low probability of progressing to acute leukemia or myelofibrosis and its prognosis is determined by thromboembolic or bleeding symptoms, the treatment of this disease is aimed at preventing vascular events. We encountered a nonagenarian patient with ET who presented with acute myocardial infarction with ST-segment elevation. In the present case, the patient was 91 years old, and antithrombotic agents were required after the placement of drug-eluting stent. Therefore, we decided not to perform cytoreductive therapy because the risk of bleeding is higher. Very elderly patients with ET are at an increased risk of thrombotic and hemorrhagic events. The risk-benefit of antithrombotic therapy should be considered individually.