A 42-year-old female with post medical history of uncontrolled hypertension presented with the complaint of intermittent cough, chest discomfort and dyspnea for more than one year. Anti-inflammatory therapy was given for cough and dyspnea but the symptoms aggravated gradually. A chest X-ray (CXR) revealed right upper mediastinal haziness and Computed Tomography (CT) showed a possibility of right subclavian artery aneurysm (Fig 1). On physical exam, no difference in blood pressure was noted between the two arms. Trachea was slightly shifted to the left. Chest auscultation revealed decreased air enter in the right upper lobe with no rhonchi and crepetations. Right radial artery pulse was weaker as compared to the left radial artery.

After successful general anesthesia, a median incision over sternum was made to divide sternum longitudinally so as to expose and protect right phrenic nerve, left and right innominate veins and superior vena cava. A huge lump was detected over right neck and right superior mediastinum, upper boundary of which extended to lower pole of thyroid gland, lower boundary was over aortic arch and ascending aorta. The lump was not pulsatile. Proximal end of tumor body was 2 cm away from the origination of subclavian artery, while edge of distal part was not clear. Superior vena cava and left innominate vein were compressed to the right by the tumor, right innominate artery and common carotid artery pressed toward the left, and trachea deformed toward left. Tumor body was closely adhered to the above mentioned arteries and retrosternal tissues. We cautiously dissociated and blocked originations of right innominate artery, right common carotid artery and right subclavian artery. A transverse infraclavicular incision was made over right midciavicular line to expose axillary artery, and then covered a blocking belt over there. After blocking originations of right axillary artery and subclavian artery, body of aneurysm was incised. It was observed that right vertebral artery was breached on posterior wall of the tumor body with massive bleeding, so suture was performed. According to exploration, the aneurysm cavity was about 7×7×6cm in size. The cavity was kept exclusion after aneurismal sac suture. Origination of right subclavian artery and proximal end of right axillary artery were ligated, and an artificial ePTFE blood vessel with stent, 6mm in diameter, was grafted over distal end of ascending aorta and right axillary artery. Anastomosis was performed after venting (Fig 4). Blood flew fluently, and there was no hemorrhage over stoma.

Subclavian artery aneurysm is an extremely rare entity while true atherosclerotic aneurysm is even more rare. Dent et al have reported that only 2 out of 1488 cases of atherosclerotic aneurysm had subclavian artery aneurysm, with an incidence of about 0.13% (1). The most common causes of subclavian artery aneurysm are atherosclerosis, trauma and post-stenotic dilated aneurysm secondary to thoracic outlet syndrome, besides, the rare causes include infective, syphilitic media necrosis and so on (2). Symptoms of subclavian artery aneurysm are determined by the aneurysm site and size. Extrathoracic aneurysm usually presents with pulsatile lump over supraclavicular fossa with pulsation and vascular murmurs; whereas intrathoracic aneurysm or post-stenotic dilated aneurysm compress brachial plexus or upper extremity vessels leading to the ischemia of the limb; while tumor body eroding apex of lung might cause hemoptysis; compress recurrent laryngeal nerve resulting in hoarse voice; besides, there are reports about dysphagia and Horner’s syndrome as well (3), however, dyspnea caused by trachea compression is seldom reported.