A 52-year-old man was admitted to our hospital for mediastinal mass found incidentally in health examination. He had no special disease history or any symptoms. No face or upper extremity edema was found in physical examination. Enhanced chest computer tomography (CT) showed a size of 5.6*4.3 cm mass in anterior mediastinum, which was enhanced in the artery phase (Fig. ), and it had no clear boundary with left innominate vein and SVC. The CT report suggested high possibility of thymoma. Echocardiographic examination did not reveal any abnormality. Thymoma was diagnosed and he received operation in our hospital through median sternotomy on July 2019. During the operation, a dark red and saccular mass was found in anterior mediastinum with slight pulsation. The mass had no clear boundary with left innominate vein and further exploration revealed they were connected with each other. The membrane of the mass seemed to be very thin and easily bled when touched. Left innominate venous aneurysm with part of SVC involved was highly suspected.\nThe venous aneurysm was resected with the proximal and distal end of the left innominate vein blocked (Fig. ). However, the majority of the left innominate vein wall was involved and only a little part of vessel wall was left after the venous aneurysm was resected, which made the reconstruction of the left innominate vein necessary. Because of the misdiagnosis and lack of abundant preoperative preparation, we decided to take pericardium as material for repairment and reconstruction. We first resected the involved part of SVC with it blocked, and repaired it with a small piece of pericardium. The SVC was unblocked immediately after repairment was finished. Then we took a large piece of pericardium and wrapped it around a needle tube, suturing the two sides to make it a tube in shape with the smooth surface inside (Fig. ). The tube was first anastomosed to the distal end of the left innominate vein. Then we blocked the SVC again and opened a small hole in the side wall and anastomosed the other side of the tube with SVC. The reconstructed left innominate vein and SVC seemed patent and firm (Fig. ). Low molecular heparin was used once per day just for routine anticoagulation after surgery. The patient had an uneventful postoperative course and was discharged 6 days after surgery. He did not take anticoagulant drugs after discharge and was satisfied with the treatment therapy. The pathological diagnosis was mediastinal hemangioma. The patient kept in good condition on the last follow up date of December 2019.
A 73-year-old female presented as an outpatient from her primary care physician for a CT of the thorax, abdomen, and pelvis to evaluate a reportedly stable abdominal aortic aneurysm. Pertinent past medical history revealed a left supraclinoid internal carotid artery aneurysm, a stable infrarenal abdominal aortic aneurysm, systemic lupus erythematous/rheumatoid arthritis overlap syndrome, smoldering IgG lambda myeloma, chronic kidney disease (stage II), hyperparathyroidism, and a cerebral infarction in the right posterior cerebral artery territory in 2009. Findings on the CT of the thorax demonstrated a fusiform superior vena cava (SVC) aneurysm measuring 5.9 × 4.4 × 6.1 cm (anterior-posterior × transverse × craniocaudal). No thrombus was noted within the SVC aneurysm (). The aneurysm was first partially visualized in 2007 on a cervical spine CT, and since that time it had remained stable on annual follow-up CTs.\nThe patient's course between 2007 and the most recent study in 2016 included an extensive rheumatologic and hematologic workup, including a temporal artery biopsy in 2015. Pathology revealed intimal hyperplasia with focal internal membrane disruption, but no features of granulomatous vasculitis were identified.\nThe etiology of the SVC aneurysm in this patient is uncertain. Potential causes in this patient include autoimmune disease (RA/SLE), which seems unlikely. Pathology did not reveal any convincing evidence of vasculitis. The arterial aneurysms are also felt to be unrelated as the patient has significant atherosclerotic disease. While an iatrogenic cause is possible, a chart review did not elicit any complications relating to prior hemodialysis catheter placement. Therefore, we surmised that the SVC aneurysm was likely idiopathic.\nThis patient did not receive any anticoagulation to prevent thrombus formation within the SVC aneurysm, and no repair was ever attempted. For the six years during which the patient was under observation at our institution, an SVC thrombus or sequela of an embolus originating from the SVC has never been observed. While the patient had a cerebral infarct in 2009, there was no evidence of right to left circulatory shunt. The observatory management of the SVC aneurysm in this patient stands in contrast with the majority of the cases found in the literature. Most patients were treated prophylactically for theoretical complication.