Portal vein aneurysm (PVA) is a vascular anomaly characterized by a focal, fusiform, or saccular dilation of the portal vein, defined as a diameter greater than 1.5 cm in normal livers and 1.9 cm in cirrhotic patients. [1,2]

PVA is a rare condition, with approximately 200 cases reported in the literature. Although PVAs account for less than 3% of all visceral aneurysms, they represent the most common type of visceral venous aneurysm. The most frequent sites are extrahepatic, with the common portal trunk being involved in about 80% of cases, while the confluence with the splenic vein and the superior mesenteric vein accounts for less than 20%. [3,4]

The etiology of PVA is multifactorial. It can be congenital, due to an inherent weakness in the venous wall or incomplete regression of the primitive distal vitelline vein. Alternatively, it can be acquired, associated with conditions such as portal hypertension in cirrhosis, trauma, pancreatic surgery, liver transplantation, severe pancreatitis (due to the action of pancreatic enzymes), malignant invasion, or systemic factors such as thrombophilia or myeloproliferative disorders.

The clinical presentation of PVA depends on its location and size. In most cases, PVA is asymptomatic and diagnosed incidentally during imaging studies performed for unrelated conditions. When symptomatic, presentations vary and may include abdominal pain, nausea, vomiting, signs of portal hypertension (such as variceal bleeding), or organ compression leading to swelling and jaundice.

The prognosis of PVA is generally favorable, particularly in asymptomatic cases. Early diagnosis is crucial for optimizing outcomes and preventing potential complications, such as aneurysm rupture, compression of adjacent structures, or thrombosis.