Portal Vein Aneurysm Mimicking a Liver Nodule

liver and the pancreatic head, apparently adjacent to the portal vein trunk, with positive Doppler sign (Fig. 1). At this point, the lesion was considered to be of vascular nature, and as the patient refused magnetic resonance imaging (MRI) due to claustrophobia, an abdominal computed tomography (CT) scan was performed, describing a normal liver and a portal vein trunk aneurysm with a 35-mm diameter, without thrombosis or compression of adjacent structures (Fig. 2). After multidisciplinary discussion, conservative management with clinical and Doppler ultrasound surveillance of complications such as thrombosis or compression of structures was proposed to the patient, and no such events occurred during 1 year of follow-up. Portal vein aneurysms, defined as a portal vein diameter exceeding 19 mm in cirrhotic patients and 15 mm in noncirrhotic ones, are extremely rare, with about 200 cases published, most being extrahepatic [1]. A proportion is believed to be congenital due to incomplete regression of the right primitive distal vitelline vein, explaining its presence in patients with no history of cirrhosis, pancreatitis, abdominal trauma or malignancy [2]. Half of the patients present with nonspecific abdominal pain and less than 10% have a serious complication, with spontaneous rupture being unfrequently reported [1]. Abdominal Doppler ultrasound and especially CT and MRI are helpful for the diagnosis, evaluation and determining of the exact location of the aneurysm.