A 93-year-old male presented to the emergency department with a few day history of worsening cough and shortness of breath. Examination showed a mildly raised JVP and scattered bilateral lung crepitations. A plain chest film confirmed cardiomegaly and signs of pulmonary congestion. Blood tests were generally unremarkable. Patient was given oxygen and started on Furosemide however due to on-going hypoxia a CT pulmonary angiogram was performed and ruled out pulmonary emboli however revealed a vascular abnormality which had 5x3 cm sac situated behind the trachea at the level of the bifurcation, consistent with a large azygos vein aneurysm (Figure 1).

The patient's symptoms gradually improved over the coming days and he was eventually discharged home on Furosemide. The vascular abnormality was managed conservatively and is felt to be an incidental finding that requires no dedicated follow-up in this particular case given the patient's age and co-morbidities.

Aneurysms of the azygos vein are rare findings and the aetiology is often unclear. They can be idiopathic or can occur in patients with congenital malformation of the inferior vena cava or more commonly secondary to high central venous pressures due to heart failure or portal hypertension [1]. Patients are usually asymptomatic however if the aneurysm gradually becomes enlarged, it can cause pressure effects on adjacent structures such as the superior vena cava or the right main bronchus. Patients with this pathology are often identified after having a chest radiograph that shows an incidental paratracheal density, mimicking a mediastinal mass. The size of the aneurysm may fluctuate with respiration, especially if a chest radiograph is taken whilst the patient performs the Valsalva maneuver. Contrast enhanced cross-sectional imaging is important in establishing its vascular nature so as to prevent potentially hazardous diagnostic procedures such as endobronchial ultrasound-guided transbronchial needle aspiration. There is no consensus as for the management of azygos aneurysms. It is generally felt that conservative management with long-term follow-up is most appropriate if the aneurysm is asymptomatic and uncomplicated, however surgical resection should be considered if the patient starts experiencing compression symptoms or the aneurysm develops intra-luminal thrombosis or thromboembolic disease (especially in the case of saccular aneurysms which pose a greater risk of complications) [2] [3]. Endovascular therapy can be considered as a successful alternative to surgery. However few cases have been documented in literature given the low prevalence of this pathology [4].

Azygos vein aneurysms are rare occurrences and are often diagnosed incidentally. Conservative management with long-term follow-up is usually indicated if the aneurysm is uncomplicated.

Keywords: Azygos vein, Aneurysm, Vascular abnormality

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2. Ko SF, Huang CC, Lin JW, et al. Imaging features and outcomes in 10 cases of idiopathic azygos vein aneurysm. Ann Thorac Surg 2014 Mar;97(3):873–8.   [CrossRef]   [Pubmed]    
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