Nontraumatic pseudoaneurysm of the proximal ulnar artery with eosinophilia.

Proximal ulnar artery aneurysms, including pseudoaneurysms, have not been described in the English literature. We report a nontraumatic pseudoaneurysm of the proximal ulnar artery with eosinophilia in a 54-year-old man. Radial, coronary, and hepatic artery aneurysms associated with eosinophilia in idiopathic hypereosinophilic syndrome or allergic granulomatous angiitis (Churg Strauss syndrome) have been reported. Although it is unclear in the present case whether eosinophilia was associated with the pseudoaneurysm of the ulnar artery, eosinophil infiltration into the aneurysmal wall may have influenced vascular injury as the cause of the pseudoaneurysm formation.