Pseudoaneurysm of the brachiocephalic artery.

Pseudoaneurym of the brachiocephalic artery is uncommon. A 62-year-old male patient with a mediastinal tumor underwent tumor resection at the Department of Thoracic Surgery in our hospital. Urgent transverse aorta-right common carotid artery bypass with an 8-mm prosthetic graft was performed intraoperatively, due to uncontrolled bleeding from the brachiocephalic artery where severe adhesion between the anterolateral aspect of the brachiocephalic artery and the tumor was encountered. After surgical removal of the tumor, frozen-section analysis revealed no malignant cells in the tumor, which instead comprised hematoma with organized changes and no evidence of malignancy. Based on pathological results, the resected tumor was diagnosed as a pseudoaneurysm of the brachiocephalic artery. Postoperative course was uneventful. Cause of the pseudoaneurysm was considered iatrogenic, as the aneurysmal wall displayed no atherosclerotic degeneration, and although no history of blunt trauma to the chest or central venous puncture was present, the patient had undergone cerebral artery angiography via the right brachial artery following right thalamic hemorrhage 2 years earlier.