I am going to have to permit that as a correct answer...becos with an anomalous left pulmonary artery ( due to failure of left 6th aortic arch ) the left pul art originates from the rt. pul art and pushes the trachea to the right. You may get some wheezing with pulmonary artery sling, esp on the rt. side, because the rt main bronchus is compressd but you won't get stridor. This CXR should give U the hint.
From the barium swallow above, this is a double aortic arch. I agree that the top image could easily have been a pulmonary sling, but as neo-star said it wouldn't explain the stridor
Answer: Double aortic Arch Credit to Dr. bb100 for initiating a good discussion and providing very valid differentials and to Dr. kangourou for clinching the diagnosis. We only think of solid masses in our differentials for mediastinal masses...the idea of posting this challenge was to induce some thought into vascular rings being one of the differentials for mediastinal masses causing a widened mediastinum or mediastinal shift. (Y)
Related Self Assessment Question A newborn infant displays wheezing respiration, which is aggravated when she feeds, flexes her neck, and/or cries. Radioimaging studies of her chest reveal a double aortic arch compressing her trachea and esophagus. This rare developmental defect results from persistence of the right dorsal aorta, which normally disappears. The arch of the aorta arises from which of the following structures? A. fifth pair of aortic arches B. fourth pair of aortic arches C. second pair of aortic arches D. sixth pair of aortic arches E. third pair of aortic arches EXPLANATION: The arch of the aorta is formed from the left fourth aortic arch. Part of the right fourth aortic arch becomes the proximal portion of the right subclavian artery, whereas the rest of the fourth arch disappears. However, if it persists, a right aortic arch is formed passing posterior to the trachea and esophagus. With the formation of the normally occurring left aortic arch, which runs anterior to the trachea and esophagus, a double aortic arch is created. This defect clamps the trachea and esophagus resulting in the respiratory symptoms. The second pair of aortic arches (choice C) partially form the stapedial arteries in the middle ear of the embryo. The third pair of aortic arches (choice E) form the common carotid arteries and contribute to the internal carotid arteries. The fifth pair of aortic arches (choice A) either does not develop or form primitive vessels, which disappear eventually. The sixth pair of aortic arches (choice D) contribute to the formation of the pulmonary arteries and ductus arteriosus. The answer is B.
