The aberrant right subclavian artery (arteria lusoria) is not uncommon; the prevalence of this vascular variant is appreciated to be in the range of 0.5-2%. 

When a dissection occurs distal to the aortic arch vessels, it is usually propagated distally to the descending and eventually abdominal aorta, inluding branching vessels. It might however also spread proximally, which in a patient with normal vascular anatomy in turn would involve the left subclavian artery, the left common carotid artery and the innominate artery. In this patient however, the first (=most distal) aortic arch vessel to be involved in the dissection was the aberrant right subclavian artery, with no involvement of the other aortic arch vessels. This explains the somewhat unusual clinical presentation with chest pain radiating to the right but not the left arm.

This particular case (as well as other cases of dissections beginning distal to the arch vessels but with retrograde involvement of the same vessels) poses a challenge of classification. It has been proposed that such pattern be classified as a type B dissection with aortic arch involvement ¹.