A Large Superior Gluteal Artery Pseudoaneurysm Masquerading as a Pelvic Mass: When Not to Biopsy

A superior gluteal artery pseudoaneurysm is a rare vascular lesion that can mimic soft tissue masses, creating diagnostic uncertainty and posing significant risk during biopsy or intervention. This case describes a patient with a superior gluteal artery pseudoaneurysm and associated arteriovenous fistula (AVF) initially mistaken for a piriformis mass. We discuss the clinical presentation, emphasize the imaging findings that facilitated accurate diagnosis, and outline the endovascular techniques used to achieve occlusion of the pseudoaneurysm and associated AVF.