V Aortic Arch Remnant

Abstract

Here, we describe the case of an asymptomatic 70-year-old male patient who performed a contrast-enhanced computed tomography examination for prostate cancer staging, and an exceptional finding was reported. Specifically, a probable and never before reported minimal V aortic arch remnant with a thin intima-media band that joins together the anterior and posterior aortic walls.

Keywords: Weinberg classification; aorta; computed tomography; congenital anomaly; fifth aortic arch; improved classification; remnant; thoracic; type A; type A1.

Figure 1

Axial (A), oblique sagittal (B,C), and oblique coronal (D) computed tomography images in an asymptomatic 70-year-old male patient who performed a computed tomography examination for prostate cancer staging. Images (A,B) could be misinterpreted as type A aortic dissection. However, looking at the oblique images (C,D), is evident that this is not the case—in fact, these images show that a thin line connects the anterior and posterior aortic walls, and it seems to be constituted by intima and media layers. Volume rendering (E) shows a small area with absent contrast enhancement, and the virtual endoluminal images (F,G,H) clearly show the stripe connecting the opposing walls. This seems to be a congenital anomaly due to a minimally imperfect aortic arch formation, and it could be a fifth aortic arch remnant. The patient underwent a cardiac surgery visit, and no follow-up was scheduled. The patient did not show any symptoms related to this condition two years post the computed tomography examination. Previously published articles reported aortic arch anomalies, in particular persistent fifth aortic arch (PFAA), which [1,2,3,4] has been classified into three types by Weinberg. Subsequently, an improved classification divided PFAA into four types based on its anatomical origin and hemodynamic changes. In particular, the imaging findings in our case suggest that it could belong to a previously unreported subtype of type A of the Weinberg classification and type A1 of the improved classification, which are characterized by a double-lumen aortic arch where two parallel arches coexist, with the innominate, left common carotid, and left subclavian arteries arising from the more superior arch, probably as derivatives of the normal embryonic fourth branchial arch [3,5,6]. The persistence of the fifth aortic arch is usually of no hemodynamic significance and it is incidentally diagnosed when it is characterized by a double-lumen aortic arch without other vascular malformations [5]. To the best of our knowledge, no previously published article has reported such an image of the thoracic aorta, so this case can expand the spectrum of aortic arch anomalies.