We report the case of a 62-year-old man who experienced a left axillary artery pseudoaneurysm that was secondary to nonunion of a 30-year-old left midshaft clavicle fracture. He initially underwent endovascular repair using a self-expanding nitinol stent graft, which was perforated at postoperative day 5. Therefore, we performed open repair with concomitant clavicle resection, and no complications were observed during an approximately 6-year follow-up. We recommend performing clavicle resection with vascular repair to prevent recurrence in similar cases.Keywords: axillary artery pseudoaneurysm, clavicle nonunion, early stent graft perforation clavicle. Computed tomography (CT) revealed nonunion of a 30-year-old left midshaft clavicle fracture after improper fixation using a wire (Fig. 1A). The patient also reported experiencing paresthesia around his left shoulder at approximately 1 month before his admission. Enhanced CT revealed a pseudoaneurysm that originated from the first segment of the left axillary artery at the first rib (Fig. 1B). Based on these findings, the patient underwent EVT using a self-expanding Fluency Plus stent graft (10 mm × 40 mm). He reported that the pain resolved immediately and the abnormal pulsation disappeared. Therefore, he was discharged at postoperative day 5, and was cautioned to avoid abduction movement (>90°) of his left upper limb.However, the same pain and abnormal pulsation returned on the night after his discharge. He was re-admitted to our hospital and underwent CT and angiography, which revealed a recurrent pseudoaneurysm due to stent graft perforation ( Fig. 2A-2C). Both the covering graft material and the stent structure were compromised, and the stent was dilated and perforated at the midpoint (type III endoleak), although no type I or type II endoleaks were observed. Therefore, two balloon catheters were placed proximal and distal to the perforation, and were inflated to control the pressure in the pseudoaneurysm.The patient was then transferred to the operating theater for resection of the pseudoaneurysm. A diagonal skin incision was made across his clavicle (from the upper proximal side to the lower distal side), and we resected a part of the clavicle that was proximal to the nonunion. We also attempted to dissect the proximal and distal axillary arteries outside the pseudoaneurysm. However, severe adhesion made the dissection difficult, and although we secured the distal axillary artery, we could not secure the proximal axillary artery. There was a risk of brachial plexus injury if we performed further dissection, and we elected to open the pseudoaneurysm. We controlled the bleeding from the perforation digitally, placed a proximal vascular clamp (as well as a distal clamp after dissecting the vessel), and removed the stent graft. Next, we replaced the injured vessel with a 10-mm woven double velour tube