A rare cause of esophageal dysphagia due to dilatation of azygos vein

Dysphagia is defined as an inability to swallow or difficulty in the passage of food from the mouth to the stomach due to functional or mechanical obstruction of the luminal organ, including the oropharynx, esophagus, or gastric cardiac. The azygos vein (AV) begins as the confluence of the upper lumbar and right subcostal veins before it enters the thoracic cavity. It runs closely alongside the esophagus and thoracic duct through the posterior mediastinum, and it receives contributions from the left-sided hemiazygos and accessory hemiazygos veins. The AV arches over the esophagus anteriorly before draining into the superior vena cava. Due to its close anatomical proximity to the esophagus, the AV can potentially cause dysphagia if significant pathology is present. The etiologies of esophageal dysphagia can be divided into structural and motor disorders. The structural disease can be further subdivided into intrinsic and extrinsic causes. External vascular compression is a rare but crucial consideration in diagnosing dysphagia, often linked to arterial abnormalities. Among these, an aberrant right subclavian artery – known as arterial lusoria – is the most common. In contrast, venous abnormalities are even less likely to cause a mass effect due to their relatively soft, compressible structure. Azygos vein aneurysms are uncommon and infrequently diagnosed.