Aneurysm of an aberrant right subclavian artery

Although an aberrant right subclavian artery is the most common congenital anomaly of the aortic arch, with an incidence of one in 200 (Grainger & Allison, 1986), aneurysmal dilatation of this aberrant vessel is quite uncommon. In this report we describe one case which presented initially with a diagnosis of aneurysm of the thoracic aorta. A 72-year-old man was admitted to another hospital for transurethral resection of the prostate. His medical history was unremarkable and he had no other symptoms apart from those relating to his urinary tract. A pre-operative chest radiograph (Fig. 1) showed a bilateral but asymmetrical superior mediastinal mass lying mainly to the left of the midline. The outline of the aortic knuckle was lost and a small curvilinear fleck of calcium was noted in the left lateral margin of the mass (arrowed, Fig. 1). A lateral radiograph of the chest confirmed that the mass did not lie in the posterior mediastinum and a diagnosis of aneurysm of the thoracic aorta was thought most likel...