Portal vein aneurysms are rare vascular abnormalities, many of which are incidentally discovered on routine imaging studies. The etiology of portal venous aneurysms is poorly understood, and the management of these lesions is debatable. We report the case of a 61-year-old woman with extrahepatic portal vein aneurysm. We review the nature and significance of this abnormality and discuss appropriate clinical, imaging, and treatment approaches.