Subclavian artery aneurysm in association with congenital absence of ipsilateral internal carotid artery.

Aneurysms of the subclavian artery are rare. Similarly, congenital absence of the internal carotid artery is an extremely rare vascular anomaly. In this report, we discuss the case of a 54 year-old woman with an unusual aneurysm of the right subclavian artery in association with congenital absence of the right internal carotid artery. The aneurysm was successfully surgically repaired. On the basis of the appearance of the aneurysm and the absence of known atherosclerotic risk factors in this patient, it is hypothesized that the aneurysm is, in fact, congenital and related to anomalous development of the embryonic aortic arch branches.