7 Aberrant Right Subclavian Artery

Clinical Presentation

Asymptomatic 42-year-old man

Radiologic Findings

Coned-down PA (Fig. 7.1) and lateral (Fig. 7.2) chest radiographs demonstrate a left aortic arch and a tubular opacity (asterisk) that arises from its superior aspect, projects over the tracheal lumen, and courses obliquely toward the right upper extremity (Fig. 7.1). Note the presence of an accessory azygos fissure. The lateral radiograph (Fig. 7.2) demonstrates a soft-tissue opacity (double asterisk) that produces mass effect on the dorsal trachea. Contrast-enhanced chest CT (mediastinal window) (Figs. 7.3, 7.4) demonstrates an aberrant right subclavian artery (arrow) (Fig. 7.3) that arises from a diverticulum of Kommerell (arrowhead) (Fig. 7.4).

Diagnosis

Aberrant Right Subclavian Artery

Differential Diagnosis

None

Fig. 7.1

Fig. 7.2

Fig. 7.3

Fig. 7.4 (Images 7.1–7.4 are courtesy of Maysiang Lesar, MD, National Naval Medical Center, Bethesda, Maryland.)

Discussion

Background

An aberrant right subclavian artery arises as the last branch off a left-sided aortic arch and courses obliquely and superiorly behind the trachea and esophagus to resume its normal course. It is typically an isolated anomaly, represents one of the most common aortic arch branching anomalies, and affects up to 0.5% of the population, with a reported prevalence of 0.4–2%.