Ann Thorac Surg 2007;84:640-642
© 2007 The Society of Thoracic Surgeons
Case Reports
Innominate Venous Aneurysm Presenting as a Rapidly Expanding Mediastinal Mass
Riad B.M. Hosein, MRCS(Ed)a,
Katherine Butler, MRCPCHb,
Paul Miller, DCH, FRCPb,
Timothy Jones, MD, FRCS(CTh)a,
William J. Brawn, FRCS, FRACSa,
David J. Barron, MD, FRCS (CT)a,*
a Department of Cardiac Surgery, Diana Princess of Wales Children’s Hospital, Birmingham, England, United Kingdom
b Department of Pediatric Cardiology, Diana Princess of Wales Children’s Hospital, Birmingham, England, United Kingdom
Accepted for publication March 1, 2007.
* Address correspondence to Dr Barron, Department of Cardiac Surgery, Birmingham Children’s Hospital, Steelhouse Ln, England, B4 6NH, United Kingdom (Email: david.barron{at}bch.nhs.uk).
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Abstract
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Thoracic venous aneurysms are extremely rare conditions. Only 14 innominate venous aneurysms have been reported in the literature. We report a case of a 13-year-old girl who presented with a mediastinal mass on chest roentgenogram, which was performed because the patient was postoperatively tachypneic after a routine appendectomy. Further investigations revealed a large left innominate venous aneurysm that was growing rapidly. The patient underwent aneurysmectomy and reconstruction of the innominate vein. The patient’s postoperative course was uneventful, and her respiratory symptoms resolved.
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Introduction
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Thoracic venous aneurysms are extremely rare conditions. Only 14 innominate venous aneurysms (IVAs) have been reported in the literature. They may be completely asymptomatic, presenting as an incidental finding or as a result of complications they cause.
A 13-year-old girl had been investigated for an unproductive cough of 2 years duration and had been given a presumptive diagnosis of asthma. No radiologic examination had been performed. However, after an uneventful appendectomy for acute appendicitis she was noted to be tachypneic and a chest roentgenogram was performed. The chest roentgenogram demonstrated a large mass in the superior mediastinum with a well-defined smooth lateral border with a normal appearance of the right hemithorax (Fig 1a). There was no history of clavicular fracture or local trauma and central venous cannulation of the neck had not been performed or attempted in the perioperative period.
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Fig 1. (a) Chest roentgenogram showing a large mass (A) in the middle mediastinum with a well-defined smooth curvilinear lateral border with a normal appearance of the right hemithorax. (b) A contrast computed tomographic scan showed a large venous aneurysm extending from the region of the left innominate vein with clot and sac.
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Examination was unremarkable with the exception of mildly reduced air entry on the left with no evidence of upper limb or facial suffusion. Inflammatory markers were normal.
Contrast enhanced computed tomographic scan was performed locally, which revealed a mass of 7 x 8 cm that appeared to arise from the underside of the innominate vein. There were no filling defects within the aneurysmal sac, and patency of the subclavian vein and superior vena cava were noted. She was referred for specialist care and a repeat contrast computed tomographic scan (Fig 1b) 10 days later showed expansion of the venous mass extending from the region of the left innominate vein, measuring 11.5 cm x 8.5 cm. The innominate vein was occluded with contrast refluxing into the left jugular vein and around the clot within the aneurysm. The left pulmonary artery was patent but compressed by the mass. There was some atelectasis at the left lung base most likely due to compression, and the lung parenchyma was otherwise normal.
In view of the rapid increase in size of the aneurysmal mass and the appearance of fresh thrombus, an angiographic study was performed through the femoral artery. This did not demonstrate any arterial feeding vessels.
The mass arose from the leftward and underside of the innominate vein (Fig 2a). It extended into the left pleural space and was adherent to the mediastinal pleura but not to the lung.
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Fig 2. (a) Intraoperative picture showing A, the heart, B, the aneurysm, and C, the left lung. (b) Open excised aneurysmal sac showing sac and clots.
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The mass was saccular in shape measuring 20 cms in length and 15 cm in its maximum diameter, and it arose from a 5-cm wide origin from the leftward end of the innominate vein. The mass was tense and relatively smooth walled with some varicose irregularities on the surface. Opening the mass revealed both fresh and old thrombus (Fig 2b). The wall was approximately 3-mm thick.
A median sternotomy was performed. The mammary vessels were divided and ligated to enable mobilization anteriorly. Cardiopulmonary bypass was established between the ascending aorta and a single right atrial cannula to reduce the tension in the mass to allow for further, safe mobilization and to prevent possible embolization. The neck of the aneurysm and the left subclavian and jugular veins were controlled.
The patient was cooled to 18°C, and the aorta was cross-clamped and the heart was arrested.
The vein was opened longitudinally where a fresh clot was found. Complete excision of the mass was performed, leaving a 7 cm defect in the underside of the innominate vein. The edges were cut back to normal venous tissue. All clots were removed. The vein bled back through both proximal and distal ends. Bypass was recommenced with a snare around the left innominate vein and around the insertion of the innominate vein into the superior vena cava. The air was removed from the heart and the cross clamp was removed.
The underside of the vein was reconstructed with a patch of bovine pericardium (Fig 3). The snare was removed after full re-warming.
The patient had an uneventful postoperative course. The innominate vein was well visualized with good flow and no intraluminal thrombus by postoperative echocardiography. The left pulmonary artery, which was previously compressed by the venous mass, appeared normal. Her cough completely disappeared. Histology showed a saccular aneurysm comprising a large ectatic vein. The lumen of the aneurysm contained new and organized thrombus. Microscopy revealed no organisms of either aneurysmal tissue or blood cultures.
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Comment
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Venous aneurysms are rare without established cause and may be completely asymptomatic, presenting as an incidental finding [1, 2].
Potential causes include congenital malformations, trauma, inflammation, infection, and degenerative changes in the vessel wall [3]. In a single case, congenital absence of the longitudinal muscle coat of the adventitia has been reported [4]. There has also been an association between cystic hygromas and venous aneurysms and a common origin of both lymphatics and venous drainage reported [5]. Their clinical significance arises from the complications that they can cause.
These complications include: (1) the risk of thromboembolism and venous obstruction, (2) the risk of rupture [6] (ie, traumatic [such as line insertion] or spontaneous), and (3) compression of bordering structures. These features need to be taken into account when planning management, which may be conservative for small, nonexpanding aneurysms [7].
In this case, the size, the rapid expansion, and the development of fresh thrombus within the aneurysm precluded conservative treatment.
The appendicitis seemed to be incidental, but serendipitously led to the diagnosis being made. The chronic cough was most likely related to the bronchial irritation and atelectasis caused by the tumor and would suggest that it had been growing for a period of years.
A rapidly growing mass is an alarming diagnostic dilemma. Differentials included malignant disease (ie, primary and secondary lung cancers, lymphoma), benign developmental tumors (ie, neurofibromas, teratoma, and bronchial cysts), and arterial aneurysms. Cross-sectional imaging, either as magnetic resonance imaging or computed tomography are sufficient for accurate diagnosis of venous and arterial aneurysms and allow for planning of surgical strategy [8]. Cardiopulmonary bypass will often be necessary to allow for safe mobilization and resection. The prognosis after successful resection is very good. There are no reported cases of recurrence or of the development of similar lesions elsewhere. These unusual aneurysms should not be forgotten in the differential diagnosis of a mediastinal mass. Despite being a benign lesion and at low pressure, these masses can rapidly enlarge once they reach a critical size.
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References
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- Burkill GJ, Burn PR, Padley SP. Aneurysm of the left brachiocephalic vein: an unusual cause of mediastinal widening Br J Radiol 1997;70:837-839.[Abstract]
- Schellhammer F, Wöbker G, Turowski B. Asymptomatic aneurysm of the subclavian vein Acta Radiol 2005;46:366-367.[Medline]
- Shatz IJ, Fine G. Venous aneurysms N Engl J Med 1962;266:1310-1312.[Medline]
- Ream CR, Giardina A. Congenital superior vena cava aneurysm with complications caused by infectious mononucleosis Chest 1972;62:755-757.[Medline]
- Sabin FR. On the origin of the lymphatic system from the veins and the development of the lymph hearts and thoracic duct in the pig Am J Anat 1902;1:367-391.
- Taira A, Akita H. Ruptured venous aneurysm of the persistent left superior vena cava Angiology 1981;32:656-659.[Free Full Text]
- Tsuji A, Katada Y, Tanimoto M, Fujita M. Congenital giant aneurysm of the left innominate vein: is surgical treatment required? Paediatr Cardiol 2004;25:421-423.[Medline]
- Gozdziuk K, Czekajska-Chehab E, Wrona A, Tomaszewski A, Drop A. Saccular aneurysm of the superior vena cava detected by computed tomography and successfully treated with surgery Ann Thorac Surg 2004;78:e94-e95.[Abstract/Free Full Text]
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Abstract
Introduction
