Teaching Case

An 83-year-old woman was admitted to the emergency service of our hospital complaining of an intermittent epigastric pain for three days; abdominal distension and constipation. The patient suffered from hypertension, dyslipidemia and atrial fibrillation treated with anticoagulant therapy. The blood test showed a hemoglobin level of 6.7 g/dl.

A Computed Tomography (CT) angiography of the mesenteric circulation was performed, obtaining arterial and venous phases.
The CT angiography showed a nodule with significant contrast enhancement, similarly to arterial vessels in both phases (white arrowheads in fig. 1a-b), adjacent to the greater curvature of the stomach, compatible with visceral artery aneurysm. Moreover, there was abundant high-density ascites (up to 60 Hounsfield Units) compatible with hemoperitoneum (white arrows in fig. 1b). A perianeurysmal hematoma (black asterisk in fig. 1a-b), indicating the probable origin of the bleeding, was also observed and no active bleeding was demostrated.
The relationship between the aneurysm and the vessels was demonstrated by maximal intensity projection (MIP) reconstructions. The aneurysm was located on the left gastroepiploic artery (black arrowhead in fig. 2a) which is a branch of the splenic artery (fig. 2a) and it is anastomosed with the right gastroepiploic artery, originated from the gastroduodenal artery (fig. 2b).

The patient underwent an emergency laparotomy for clinical deterioration. Abundant hemoperitoneum and an aneurysm depending on the gastroepiploic artery were confirmed at surgery. The histological examination of the surgical specimen revealed an aneurysmal dilatation of an arterial vessel (white asterisk in fig. 3a and black asterisk in fig. 3b) with a rupture on its wall (white arrow in fig. 3a and black arrow in fig. 3b) and an infiltrating hemorrhage in the adjacent tissue. The deterioration of the histological samples did not allow us to determine the etiology of the aneurysm.

The most common visceral artery aneurysms are those affecting the splenic artery, which account for over 60 % of cases [1]. It must be taking into account that they can have complications such as compression of adjacent structures, thrombosis with or without distal embolization or hemorrhage due to rupture [1].

The incidence of gastroepiploic artery aneurysms among all the visceral aneurysms is as low as 0.2-0.4% [2]. However, rupture rates of these aneurysms of about 75% have been reported and the mortality after rupture has been reported to be as high as 70 % [2]. Given its rarity and its non-specificity symptoms, it is not surprising that it is seldom clinically suspected, being the imaging tests which often give the accurate diagnosis.

The most frequently used diagnostic procedure is multiphase CT angiography, which should be the first emergency radiological option when there is suspicion of abdominal hemorrhage of non-gynecologic origin [3]. The presence of hemoperitoneum in the CT images, manifested as high density ascites (over 30-45 HU), should cause us to look for an abdominal bleeding point [3, 4]. For that, we should have previously obtained both arterial and portal phases after intravenous contrast media injection, since active bleeding will be demonstrated in presence of contrast extravasation.

Visceral aneurysms can be congenital or acquired [5]. It is important trying to establish the cause of the aneurysm, usually combining radiological and histological findings, since it can be the manifestation of a potentially risky systemic disease. The main cause is atherosclerosis, although we must take into account other less common causes such as arteritis, fibromuscular dysplasia, connective tissue diseases, segmental arterial mediolysis, traumas or mycotic aneurysms [5, 7]. There are no established guidelines for the therapeutic management of this entity, however, emergency surgery or aneurysm embolization is usually the indicated treatment when aneurysms present complications [5- 10].

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