N. S. Ntombela; L. Lazarus & K. S. Satyapal

This report describes two cases of multiple anomalies associated with the azygos venous system. In Case 1, the hemiazygos vein drained the 9th to 11th left posterior intercostal veins. At T9 vertebral level, the interazygos vein passed obliquely and anterior to the aorta to drain into the azygos vein on the right. In Case 2, the common venous trunk formed by the accessory hemiazygos and hemiazygos veins passed anterior to the aorta to drain into the azygos vein at T9 vertebral level. These findings represent pre-aortic inter-azygos veins, which is a rare variation of the azygos venous system. Pre-aortic inter-azygos veins can mimic pathologies such as enlarged lymph nodes, tumors and aneurysms leading to misinterpretation of radiographs, computerized tomography and magnetic resonance scans. Surgeons need to be aware of this type of variation so as to avoid injury of any anomalous passing venous vessels.

KEY WORDS: Anomaly; Azygos Venous system; Pre-aortic inter-azygos vein.

NTOMBELA, N. S.; LAZARUS, L. & SATYAPAL, K. S. Pre-aortic inter-azygos veins: Two case reports. Int. J. Morphol., 34(2):495- 497, 2016.