Introduction: Superior mesenteric vein (SMV) aneurysms are a rare entity which was first described in the literature in 1982. Aneurysms in the portal venous system, which include extrahepatic portal, splenic, and superior mesenteric veins, represent approximately 3% of all venous aneurysms with a reported prevalence of 0.43%. With the advancement of abdominal imaging, SMV aneurysms are more frequently being identified. We report a case with a patient who was found to have to have a SMV aneurysm mimicking as a pancreatic head mass for the workup of abdominal pain.
Case Description/Methods: Our patient is a 73 year old female who was found to have a pancreatic head mass (2x2.4x1.9cm) that was found on imaging for workup of acute abdominal pain (Figure 1). Patient denied any weight loss and LFT’s were found to be unremarkable. For further workup, patient had EUS performed which showed evidence of a superior mesenteric aneurysm measuring 2.4 x 2.1 cm that was mimicking as a pancreatic head mass. No further intervention performed and patient’s abdominal pain resolved.
Discussion: Aneurysms in the portal venous system, which include extrahepatic portal, splenic, and superior mesenteric veins, are rare as they represent approximately 3% of all venous aneurysms with a reported prevalence of 0.43%. Etiologies for superior mesenteric aneurysms are not completely understood. A congenital etiology includes an incomplete regression of the caudal part of the right vitelline vein. Acquired causes of SMV aneurysms reported in the literature include portal hypertension secondary to chronic liver disease, pancreatitis, trauma and previous surgical intervention. Of these, portal hypertension is considered the most common cause of SMV aneurysms. This is due to intimal thickening with compensatory medial hypertrophy with fibrous tissue leading to weakening of the venous wall making it more susceptible to aneurysmal dilatation. Complications of SMV aneurysm includes thrombosis, biliary tract obstruction, inferior vena cava obstruction, duodenal compression, and rarely aneurysm rupture (up to 2.2% of cases). In asymptomatic patient’s, conservative management with follow-up imaging to assess aneurysm size is recommended. If the patient is symptomatic or has complications of a SMV aneurysm, surgical or interventional radiology intervention may be needed which may include portal venous shunt, aneurysmorrhaphy, stent graft placement and coil embolization.
