A 55-yr-old male presented with acute chest pain, dyspnea, and hypotension on December 8, 2009. The patient has been followed without any medications for incidentally detected asymptomatic SVC aneurysm for last 2 yr (, and the size of the SVC aneurysm did not change (). Chest radiography at admission showed marked widening of the right middle mediastinum due to abnormal soft-tissue density suggesting the rapid expansion of previously noted SVC aneurysm (). Echocardiography revealed marked enlargement and hypokinesia of the right ventricle (RV) with moderate pulmonary hypertension suggesting acute PE. Chest computed tomographic angiography (CTA) showed about 6.9 × 6.1 × 9.9 cm sized lobulated giant saccular aneurysm originating from mainly SVC and partially involving left brachiocephalic vein with internal thrombi (). Considerable amounts of thromboembolic filling defects in left pulmonary artery, both left and right lobar, segmental, and subsegmental arteries were also noted (). Three-dimensional reconstruction with endovascular views showed the giant saccular SVC aneurysm with 4.1 × 3.7 cm sized internal thrombi, and the thrombi protruded into the SVC through the narrow aneurysmal neck (). Venous CTA of the lower extremities and abdominal CTA showed no evidence of deep vein thrombosis or other venous aneurysms. To exclude the possible hypercoagulable status as a cause of pulmonary thromboembolism, the laboratory tests for hypercoagulability was done and revealed no abnormalities. Surgical exclusion of SVC aneurysm with pulmonary embolectomy was planned, but the patient and family refused surgery. Therefore, thrombolytic therapy using recombinant tissue plasminogen activator with the dose of 200 mg was administered intravenously for 2 hr for hemodynamically significant PTE, and the RV function and pulmonary artery pressure was normalized on FU echocardiography. However, the patient complained recurrent chest pain and dyspnea on the next day. FU CTA revealed more decreased amounts of thrombi in the left pulmonary artery and its branches, but the amounts of thrombi in the SVC aneurysm, SVC, right pulmonary artery and its branches were increased. Mobilization of thrombi from the SVC aneurysm due to thrombolytic therapy was the possible cause of recurrent PTE, and it was expected that further embolization of thrombi would be fatal to the patient. Therefore, surgical treatment was strongly recommended. Resection of SVC aneurysm and pulmonary artery embolectomy were performed successfully. At surgery, femoral arterial and venous cannulation was done to prepare for accidental rupture of aneurysm during sternotomy. After dissection of the aneurysm, the other venous cannulation at the innominate vein and isolation of the proximal and distal portion of the aneurysm was done. Under cardiopulmonary bypass, aneurysmal wall was opened longitudinally after snaring of proximal and distal portion of the aneurysm and innominate vein. Aenurysm which contained fresh thrombi was thin-walled and had relatively normal venous endothelium grossly (), and the histopathologic examination showed compatible findings of true aneurysm (). Thin-walled aneurysmal wall was completely resected and subsequent reconstruction of the superior vena cava was performed with glutaraldehyde fixed autologuous pericardium that was already harvested. Outer surface of the pericardium was buttressed with Dacron to prevent potential formation of pseudoaneurysm. A transverse arteriotomy was made in the pulmonary trunk to the left main pulmonary artery and another incision was made in the right main pulmonary artery, and the fresh and organized thrombi were gently extracted. Following the successful surgical management, the mediastinal widening on chest radiography was normalized () and the patient was recovered without any postoperative events. The patient was discharged and treated by anticoagulation with warfarin for 6 months to achieve complete resolution of the possible remained pulmonary arterial thrombi.
A 58 years-old man presented at our emergency room with fever, cough and left thoracic pain. His past medical history was unremarkable. Blood test showed WBC and C-reactive protein elevation. He had started antibiotics therapy and, given the persistence of symptoms, CT scan was performed showing lower left pneumonia. Incidentally, a 2.5 cm mass was found in the upper anterior mediastinum, with positive contrast enhancement and a 5 mm vessel arising from left brachio-cephalic vein (, ). Because of size and position fine needle aspiration nor anterior mediastinotomy were performed. Radiologic features were consistent with thymoma that usually appears as an ovoid or lobulated, smooth, well-marginated mass, projecting over the mediastinum typically protruding unilaterally, therefore patient underwent (1) neurologic evaluation that excluded myasthenia (2) PET/CT scan that showed the absence of any pathological uptake. However, thymoma was felt to remain a diagnostic possibility and patient was referred for radical surgery, with particular attention to abnormal vascularization. He underwent left thoracoscopy and, in spite of extreme attention, during pleural dissection between mediastinum and sternum, a sudden massive bleeding occurred (about 1,500 cc) requiring emergency conversion to median sternotomy. It was then clear that the bleeding came from tumor and not from brachiocephalic vein or its branches, as initially thought. After controlling the bleeding, we removed the mass but it was necessary to sacrifice the left laryngeal nerve.\nIntra-operative emergency required significant blood transfusions and precautionary transfer in intensive care for 24 h. The patient eventually made a complete recovery. We only recorded transitory dysphonia as in case of laryngeal nerve paralysis. At specimen analysis, the cut surface seemed to have some fresh blood and the soft tissue was taupe with multifocal thrombosis in various stages of organization up to phlebolithes. Histopathologically, it was diagnosed a residual thymic tissue surrounded by lipomatous hyperplasia with venous malformation consisting essentially of a large number of dilated vessels with a single layer of endothelial cells with no signs of atypia or mitosis. Most of the channels contained red blood cells in the cavity. Margins were free. Definitive histology was a 7 cm fatty specimen enclosing a 2.5 cm in size mass diagnostic for residual thymus associated with venous vascular malformation (ISSVA classification, 2008).