Medical management of a large aortic thrombus in a young woman with essential thrombocythemia

Aortic thrombus formation is rare in the patients with essential thrombocyt osis (ET); therefore, no guidelines for its management have been establishe d. Embolism from ET-associated large vessel thrombi is potentially lethal a nd has been managed surgically in a few reported cases. We describe herein a 45-year-old black woman with ET found to have a 3.5-cm, pedunculated intr a-aortic thrombus at the thoracoabdominal junction. How to treat this poten tially devastating aortic thrombus was a management dilemma. We believed, b ased on the patient's diagnosis of ET and the histology of similar thrombi in 1 reported series, that the aortic thrombus was a "white thrombus" consi sting primarily of aggregated platelets with a minimal fibrin network and a lmost no entrapped erythrocytes, The patient was treated with aspirin, 325 mg daily, as a platelet antiaggregating agent and hydroxyurea, 1500 mg dail y, to reduce the platelet count to less than 450 x 10(9)/L, The thrombus re solved without severe thromboembolic events. To our knowledge, this is the first reported case of a large intra-aortic thrombosis associated with ET t hat has been successfully managed with medical therapy alone.