Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Azygos vein aneurysm (AVA)
- Radiologic Findings
- Fig 1. Chest PA shows no significant abnormality
Fig 2. Chest CT scanogram which was obtained with supine position shows ovoid-shaped mass-like opacity in right lower paratracheal area.
Fig 3,4. Precontrast and contrast-enhanced CT scans show 3.3-cm contrast-filling space along the course of azygos arch, which is compatible with azygos vein aneurysm
- Brief Review
- - Very rare, only a few cases have been described in literature
- Cause: idiopathic (m/c), aplasia of inferior vena cava, portal hypertension, thrombosis, congenital
- Embryology: azygous arch is confluence of three embryologic veins (right supra cardinal vein, right posterior cardinal vein, and right anterior cardinal vein); therefore, it is prone to develop aneurysm
- Clinical manifestation:
- Related to their morphological characteristics, and large saccular aneurysms tend to present with chest symptoms because of the mass effect in the mediastinum
- Sluggish blood flow through the saccular AVA allows slow sedimentation and accumulation of thrombi within the lumen, leading to partial or eventual total thrombosis and progressive gradual enlargement of the AVA.
- Chest radiograph
- Well-defined mass in the area of the right tracheobronchial angle or as an enlargement of the right upper mediastinum
- Size can be changed by upright position, deep inspiration, or performing Valsalva maneuver
- CT:
- Primary modality for noninvasive diagnosis.
- Poor enhancement of the azygos vein on CT may lead to misinterpretation of AVA as neurogenic tumors or lymphadenopathies.
- Additional delay scan with optimal venous enhancement is facilitates the diagnosis of AVAs with a patent lumen
- The different levels of contrast in the aneurysm were seen with the highest density in the most posterior part
- MRI: identify thrombus or organized hematoma
- Treatment: not established. Conservative management is preferred due to meticulous ligation of azygos system and need to prevent migration of thrombus and pulmonary thromboembolism during surgery or intervention.
- References
- 1. Ko S-F, Huang C-C, Lin J-W, Lu H-I, Kung C-T, Ng S-H, et al. Imaging Features and Outcomes in 10 Cases of Idiopathic Azygos Vein Aneurysm. The Annals of Thoracic Surgery 2014;97:873-878
2. Savu C, Melinte A, Balescu I, Bacalbasa N. Azygos Vein Aneurysm Mimicking a Mediastinal Mass. In Vivo 2020;34:2135-2140
3. Braun P, Guilabert JP, Olaso LT, Aneurysm of the azygos arch, European Journal of Radiology Extra 2004:50:71-74
- Keywords