Noniatrogenic aneurysm of the distal radial artery: a case report.

Radial artery aneurysms are extremely rare. The majority are traumatic in origin and are iatrogenic pseudoaneurysms following arterial cannulation. We present an unusual case of an idiopathic isolated aneurysm of the most distal portion of the radial artery. Interestingly, upon performance of the Allen test, it was determined that the majority of blood flow to the hand was derived from the aneurysmal artery. Arteriography showed an occluded ulnar artery, a tortuous superficial palmar arch and absent deep palmar arch, and multiple small vessels that arose from the aneurysm that supplied the thumb. Given these findings, it was determined that there would be a significant risk of digital ischemia and gangrene if operative repair was attempted. A course of nonoperative management with observation was recommended.