a 60-year - old man presented to the emergency room with a sudden onset of intractable pain in the left leg .
the patient had a history of intermittent abdominal pain and hypertension without other risk factors for atherosclerosis . a computed tomographic angiogram ( cta ) revealed chronic total occlusion of the abdominal aorta from the inferior mesenteric artery level to the level of both common iliac arteries ( fig .
the cta also showed chronic total occlusion of the left external iliac artery and acute total occlusion of the left popliteal artery ( fig .
, the popliteal artery occlusion was removed , and angiography confirmed good distal run - off through the anterior and posterior tibial arteries ( fig .
however , 3 days after the procedure , the patient suffered from the same intractable pain in the left leg .
repeated femoral angiography showed a recurrence of the acute total occlusion of the left popliteal artery .
after repeated endovascular treatment , urgent surgery was performed to prevent the reoccurrence of thromboembolism .
exploration of the abdominal aorta found fresh white clots that were adherent to the aortic wall ( fig .
resection of the abdominal aorta below the inferior mesenteric artery was followed by aortic replacement with a 201010-mm dacron y graft ( meadox medicals , oakland , nj , usa ) .
distal anastomosis of the right and left arteries was performed on the common iliac artery and common femoral artery levels , respectively ( fig .
however , due to the abnormal ranges of the platelet count since the first day of admission ( ranging from 53310/l to 1,14910/l ) , a bone marrow biopsy was performed postoperatively .
the exam showed markedly increased numbers of megakaryocytes , which were clustered with mature cytoplasm and hyper - lobulated nuclei .
therefore , the final diagnosis of the patient was essential thrombocytosis ( et ) , according to the 2008 world health organization ( who ) diagnostic criteria .
medical therapy was started immediately with hydroxyurea and aspirin once daily at doses of 1,000 mg and 100 mg , respectively .
the platelet count decreased gradually and the patient was discharged on postoperative day 17 without any complications .
the therapeutic target for the platelet count ( < 40010/l ) was achieved 2 months after surgery . on the last follow - up ,
more than 2 years after the operation , the patient was in good condition with a patent graft ( fig .
et is an uncommon myeloproliferative disorder in which a proliferation of megakaryocytes in the bone marrow leads to an elevated platelet count .
et is defined by the following 4 major criteria : ( 1 ) platelet count 45010/l ; ( 2 ) megakaryocyte proliferation with large and mature morphology , and little to no granulocyte or erythroid proliferation ; ( 3 ) not meeting the 2008 who criteria for chronic myelogenous leukemia , polycythemia vera , primary myelofibrosis , myelodysplastic syndromes , or any other myeloid neoplasm ; and ( 4 ) demonstration of jak2 or other clonal markers , or no evidence of reactive thrombosis . in general , common causes of aortic thrombosis include cardiac sources of embolism , hypercoagulable states , and other complications from atherosclerotic disease .
although et remains an uncommon cause of aortic pathology , some reports have discussed cases of et - associated aortic mural thrombus . to the best of our knowledge ,
et caused a chronic obstruction of the abdominal aorta and acute obstruction of the arteries .
we encountered a fast recurrence of artery occlusion ( 3 days after thrombus removal ) .
we would have been able to prevent the recurrence of popliteal artery occlusion if we had immediately controlled the platelet count .
many options exist for managing et , such as medical therapy with heparin anticoagulation , aspirin , and cytoreductive chemotherapy , and surgical treatment with aortic thrombectomy   and/or endovascular surgery . in order to ensure the optimal treatment of et , the location of the thrombus , potential for embolism , individual risk of the patient , and the pathology of the thrombus
we decided to perform surgical treatment due to the rapid formation of the thrombus , the location of the original chronic thrombus , and the insufficiency of endovascular treatment . according to harrison et al . ,
hydroxyurea and low - dose aspirin are superior to other combinations of drugs for patients with et at high risk for vascular events , especially arterial thrombosis . in our case , once the diagnosis of et was made , the patient was treated with hydroxyurea and low - dose aspirin for a goal platelet count of < 40010/l .
the patient s platelet count was normalized and maintained within a range of 21910/l to 25210/l . in conclusion , although et rarely presents in large vessels , early diagnosis and immediate management are essential .
 essential thrombocytosis ( et ) is a myeloproliferative disorder characterized by an anomalous increase in platelet production . 
 many patients with et are asymptomatic . 
 few studies have reported et - associated thromboembolism in large vessels such as the aorta . 
 we report a patient with et who presented with peripheral embolism from an abdominal aortic thrombus and developed acute limb ischemia . 
 the patient underwent aortic replacement successfully . 
 the patient s platelet count was controlled with hydroxyurea , and no recurrence was noted over 2 years of follow - up . 
Case report
Discussion