Simultaneous occurrence of an aberrant right subclavian artery and accessory lobe of the liver.

We herein report a case showing the simultaneous occurrence of an aberrant right subclavian artery (ARSA) and accessory lobe of the liver in a 75-year-old female cadaver. In the thorax, the left aortic arch branched into the right common carotid artery, left common carotid artery, left subclavian artery, and ARSA, in that order. The ARSA was dilated at its origin to form Kommerell's diverticulum and coursed behind the esophagus. This diverticulum seemed to press the esophagus. A right-sided thoracic duct was identified that emptied into the angulus venosus. In the right-sided neck, a nonrecurrent laryngeal nerve was found. In the abdominal cavity, an accessory lobe protruded from the anterior margin of the left liver lobe. The accessory lobe was separated from the left lobe by a transverse furrow on the anterior side. We discuss possible common causes of these anomalies during development.