Question: A 68-year-old man presented with intermittent dysphagia to solids of 5 years’ duration. He denied any associated weight loss, melena, or chest pain. Physical examination was within normal limits with no pallor or lymphadenopathy. Laboratory studies, including a chemistry panel, complete blood count and liver functions were unremarkable. He underwent a barium swallow which is shown below (Figure A). On upper endoscopy, there was a bulge in the mid-esophageal region (Figure B, arrow), suggestive of an extrinsic compression with normal looking gastric and esophageal mucosa. After this, computed tomography (CT) of the chest with intravenous contrast was performed. What is the likely diagnosis? See the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI. The barium swallow revealed evidence of an oblique external compression on the mid-esophagus posteriorly (Figure A, arrow). CT of the chest (Figure C, D) showed a left-sided aortic arch with an aberrant right subclavian artery (arrow) coursing between the esophagus and the vertebral column. Dysphagia lusoria is a rare etiology of dysphagia. It is caused by an aberrant right subclavian artery, first described by a British physician David Bayford in 1794. He introduced the term “dysphagia lusoria” from “lusus naturae,” meaning dysphagia from “freak of nature.” An aberrant right subclavian artery is the most common aortic arch anomaly, present in about 0.3%–1.0% of the population.1De Luca L. Bergman J.J. Tytgat G.N. et al.EUS imaging of the arteria lusoria: case series and review.Gastrointest Endosc. 2000; 52: 670-673Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar, 2Levitt B. Richter J.E. Dysphagia lusoria: a comprehensive review.Dis Esophagus. 2007; 20: 455-460Crossref PubMed Scopus (99) Google Scholar, 3Janssen M. Baggen M.G. Veen H.F. et al.Dysphagia lusoria: clinical aspects, manometric findings, diagnosis, and therapy.Am J Gastroenterol. 2000; 95: 1411-1416Crossref PubMed Google Scholar In about 80% of the cases, it courses posterior to the esophagus, in 15% it lies between the esophagus and the trachea, and in 5% it passes anterior to the trachea.2Levitt B. Richter J.E. Dysphagia lusoria: a comprehensive review.Dis Esophagus. 2007; 20: 455-460Crossref PubMed Scopus (99) Google Scholar It causes symptoms in only a small proportion, with the mean age of presentation between 40 and 48 years.2Levitt B. Richter J.E. Dysphagia lusoria: a comprehensive review.Dis Esophagus. 2007; 20: 455-460Crossref PubMed Scopus (99) Google Scholar, 3Janssen M. Baggen M.G. Veen H.F. et al.Dysphagia lusoria: clinical aspects, manometric findings, diagnosis, and therapy.Am J Gastroenterol. 2000; 95: 1411-1416Crossref PubMed Google Scholar Barium swallow classically reveals a diagonal indentation posterior to the esophagus, coursing from the inferior (left) to superior (right) part of the esophagus. Contrast-enhanced CT confirms the diagnosis. Aortic angiography is the gold standard for demonstrating an aberrant right subclavian artery; however, because of its invasive nature and contrast exposure, it should be pursued only if surgical reconstruction is planned. Patients with mild to moderate symptoms are managed conservatively and surgery is reserved for those with persistently severe symptoms. Because this patient’s symptoms were mild and intermittent, he opted against surgery.