Splenic artery aneurysm masquerading as an intraductal tubulopapillary neoplasm diagnosed by contrast-enhanced endoscopic ultrasound

The growth of intraductal tubulopapillary neoplasms is characterized by features such as filling, expansion, and proliferation of the main pancreatic duct (MPD) [1]. The resultant obstruction to the flow of pancreatic juice leads to MPD dilatation but, unlike with intraductal papillary mucinous neoplasms, cystic lesions and mucus are not observed. Splenic artery aneurysm, which is a rare condition, mainly occurs in the distal third of the splenic artery [2]. Although splenic artery aneurysms are usually asymptomatic [3], rupture of the aneurysm can cause dramatic hypotensive shock, with a high mortality rate owing to intraperitoneal hemorrhage. Rarely, hemosuccus pancreaticus can occur because of rupture of a splenic artery aneurysm into the MPD [4]. In this condition, differentiating between an intraductal tubulopapillary neoplasm and a splenic artery aneurysm is not very challenging because splenic artery aneurysmal rupture is normally symptomatic; however, if a splenic artery aneurysm spontaneously ruptures into the MPD and immediately stops bleeding, the differential diagnosis can be challenging. We herein describe successful differentiation between these diseases using contrast-enhanced endoscopic ultrasound (EUS).