Aneurysm at junction of inferior pancreaticoduodenal arcade in the setting of distal collateralization from proximally ligated splenic artery

Visceral artery aneurysms, particularly aneurysms involving the pancreaticoduodenal arteries, are exceptionally rare and they carry the potential to be unpredictably lethal. Typically, true aneurysms involving the pancreaticoduodenal arcades occur secondary to steno-occlusion of the celiac axis. However, here we present a case of an inferior pancreaticoduodenal arcade (IPDA) junctional aneurysm secondary to chronically elevated collateral arterial blood flow from the pancreaticoduodenal arteries to the splenic artery. The patient had massive splenomegaly almost a decade after liver transplant and splenic artery ligation. There are no similar reports in the literature, and this case supports the hypothesis that chronically elevated blood flow through the small-caliber arteries predisposes to aneurysm formation.