Dysphagia lusoria is caused by compression of the esophagus from any of several congenital vascular abnormalities.
(See also Overview of Esophageal and Swallowing Disorders.)
The vascular abnormality is usually an aberrant right subclavian artery arising from the left side of the aortic arch, a double aortic arch, or a right aortic arch with left ligamentum arteriosum (1). The dysphagia may develop in childhood or later in life as a result of arteriosclerotic changes in the aberrant vessel.
Barium swallow shows the extrinsic compression, but arteriography is necessary for absolute diagnosis.
Most patients require no treatment, but surgical repair is sometimes done after careful weighing of risks and benefits.
Reference
1. Janssen M, Baggen MG, Veen HF, et al: Dysphagia lusoria: clinical aspects, manometric findings, diagnosis, and therapy. Am J Gastroenterol 95(6):1411-1416, 2000. doi: 10.1111/j.1572-0241.2000.02071.x