Teaching Case

A 50-year-old patient presented to the ER department with epigastralgia which had started around 6 hours prior. Serum lipase and creatine kinase were elevated. There was no previous history of pancreatitis.

An abdominal ultrasound was initially performed revealing a large, hypoechoic heterogeneous lesion in the epigastric region, with an anechoic area in the centre that showed the classic yin-yang sign on Doppler-US, indicating bidirectional flow (Figure 1).
Contrast-enhanced CT was then performed revealing an area of patent lumen with increased attenuation due to contrast enhancement and a large portion of the peripheral lumen showing reduced attenuation due to eccentric mural thrombus (Figure 2a). Posteriorly, a compressed but otherwise normal-appearing pancreas, with no significant peripancreatic abnormalities, could be seen (Figure 2d). There was very mild densification of the peri-aneurysmal fat, but no signs of acute haemorrhage were present.
The combination of 2D enhanced-CT images (Figure 2) and 3D reformations (Figure 3) made it possible to localise the large (8cm) aneurysm to the hepatic-splenic bifurcation of the coeliac trunk.

Coeliac artery aneurysms are extremely rare and represent approximately 4% of all splanchnic artery aneurysms [1]. Like all other splanchnic artery aneurysms, they are defined as a localised dilation of the mesenteric vasculature greater than 1.5 times the normal diameter of an artery involving all 3 layers of the vessel wall [1].
Common causes include arteriosclerosis and medial degeneration, other less common causes being trauma, dissection and Takayasu arteritis [1].

Symptomatic coeliac trunk aneurysms usually manifest initially by epigastric pain or upper gastrointestinal haemorrhage. Recent series have reported a lifetime risk of rupture of approximately 6% [2]. Calcification, aneurysm size and thrombus formation are not considered risk factors for rupture [2].

Four approaches have been described regarding splanchnic aneurysm management: no management, close observation, percutaneous intervention and open surgical repair [3]. Unlike a few other types of splanchnic artery aneurysms, which can be repaired by endovascular methods, most coeliac artery aneurysms require open repair [4].

Current guidelines for coeliac artery aneurysm repair suggest considering repair of lesions >25 mm in surgical candidates [4]. Lesions measuring 25mm or less should be monitored with contrast-enhanced CT every 3 years [4].

In our patient, due to physical examination and serum lipase levels, the diagnosis of mild acute pancreatitis was considered. Nevertheless, CT showed a compressed but otherwise normal-appearing pancreas with no significant peri-pancreatic abnormalities. Some authors have described the rare occurrence of recurrent episodes of acute pancreatitis due to aneurysmal compression [5].
Due to its size, the patient was immediately submitted to open surgical repair of the coeliac aneurysm. No significant complications ensued.