Unmasking the Uncommon Arc of Buhler Aneurysm: A Report of Two Cases.

The Arc of Buhler (AOB) is a rare embryological vascular remnant that forms a persistent arterial connection between the superior mesenteric artery and the celiac artery. Although typically asymptomatic, it assumes clinical importance in the presence of celiac artery stenosis by serving as a key collateral route. Aneurysms arising from the AOB are uncommon but carry a significant risk of rupture. This report presents two cases of AOB aneurysms identified in different clinical scenarios. The first case involved a 40-year-old woman with chronic epigastric discomfort, in whom a saccular aneurysm of the AOB was detected alongside celiac artery narrowing. The second case was of a 62-year-old man evaluated for abdominal trauma, when an incidental aneurysm of the AOB was observed on contrast-enhanced CT. In both instances, imaging revealed retropancreatic aneurysmal dilatation and stenosis of the celiac axis, suggesting altered hemodynamics with increased collateral flow as a possible cause. Key diagnostic tools include contrast-enhanced CT, CT angiography, and digital subtraction angiography. Endovascular embolization remains the preferred treatment approach, with surgical intervention reserved for select situations. Recognizing this rare vascular anomaly is essential to prevent intraoperative complications and ensure proper management. Despite its rarity, an AOB aneurysm should be considered in cases of visceral aneurysm, particularly with concurrent celiac artery stenosis.