True ulnar artery aneurysm in the upper arm: A case report and literature review.

INTRODUCTION: Ulnar artery aneurysms are rare with less than 250 previously reported in the literature. Most ulnar artery aneurysms occur distally near the palmar arch (hypothenar hammer syndrome). There are five previous reports of true ulnar artery aneurysms in the forearm; however, there are no reported cases of ulnar artery aneurysms proximal to the cubital fossa.

CASE PRESENTATION: An 87-year-old man presented with pain and a rapidly progressive median nerve palsy with a pulsatile mass in the arm. Duplex ultrasound showed an aneurysm of what was thought to be the brachial artery. CT angiography shows a high bifurcating brachial artery and true aneurysm of the ulnar artery proximal to the cubital fossa. The artery was explored and the decision was made to excise the aneurysm and ligate the artery. The patient's symptoms improved and full function was regained.

CONCLUSION: This is a rare case of such a diagnosis in the absence of a history of arterial puncture or trauma. This case demonstrates the value in obtaining detailed imaging in the work-up to aid operative decision making. We highlight the thought processes on the table in our approach to this aneurysm and report a favourable post-operative outcome at follow up.