A rare complication of splenic artery aneurysm. Mesenteric steal syndrome.

Splenic artery aneurysms are relatively common lesions that remain asymptomatic in the vast majority of patients. The commencement of symptoms is generally a morbid development because it frequently heralds either frank rupture or an erosive process that involves neighboring structures. Erosion into the splenic vein has been reported but is extremely rare. When this event occurs, the central arteriovenous fistula almost inevitably leads to a dramatic increase in portal venous pressures, which may subsequently be manifested as upper gastrointestinal tract hemorrhage. Herein, we report an unusual case of splenic artery aneurysm that was complicated by arteriovenous fistula formation in which high flow through the central splenic shunt led to the development of nontransmural small-bowel ischemia due to a mesenteric steal syndrome, which presented as acute lower gastrointestinal tract hemorrhage. Diagnostic modalities and therapeutic interventions used in this case are detailed, followed by a brief review of the pertinent literature.