Subclavian artery aneurysm with incidental bovine aortic arch branch

Aneurysms of the Subclavian artery are uncommon, accounting for less than 0.2% of all arterial aneurysms. The most common causes are arteriosclerosis, thoracic outlet obstruction, and trauma. Anomalous branching aortic arrangements are less uncommon, occurring in some 35% of subjects. We report a case of subclavian artery aneurysm in a 62-year- old man presenting with a painless right supraclavicular swelling of approximately 30 years duration. He was a known hypertensive diagnosed 21 years previously and compliant with medication. His serum lipid profile was normal. Doppler Ultrasound of the right subclavian artery showed a thin walled fusiform aneurysmal dilatation located 3.6 cm from its origin with fine internal echoes, and measuring 2.74 cm in diameter. Peak systolic velocity (PSV) within the aneurysm was 33 cm/s, compared with 55 cm/s and 45 cm/s in the right pre-aneurysmal segment and left subclavian arteries respectively. There was turbulent flow and spectral broadening within the aneurysm. Computerized Tomographic (CT) angiography of the aortic arch confirmed a right subclavian aneurysm, and showed an anomalous origin of the left common carotid and subclavian arteries. An anomalous common origin of the left common carotid from the brachiocephalic trunk representing a bovine type variant is a rare condition, its association with subclavian artery aneurysm an even rarer finding.