Abstract
Subclavian vein pseudoaneurysms are rare vascular lesions, and only a few cases have been reported in the literature, with most attributed to blunt trauma. We describe the first reported case of a subclavian vein pseudoaneurysm following percutaneous axillary lymph node biopsy. A 42-year-old woman presented with a progressively enlarging, painless right neck mass 18 months after treatment for node-positive breast cancer. Imaging with duplex ultrasound and contrast-enhanced computed tomography demonstrated a large saccular pseudoaneurysm arising from the right subclavian vein without arterial communication. Following initial observation, open surgical repair was performed via a supraclavicular approach, with excision of the pseudoaneurysm and primary repair of the vein. The patient recovered without complications and remained asymptomatic at follow-up. This case adds to the limited literature on venous pseudoaneurysms, highlights a novel iatrogenic mechanism, and supports open aneurysmorrhaphy as a safe and effective treatment option in appropriately selected patients.