Several variations of the inferior mesenteric vein have been previously described. However, this report presents a rare variation that has not yet been noted. In this case, the small inferior mesenteric vein drained into a tributary of the marginal vein, which joined the superior mesenteric vein via the middle colic vein. The superior mesenteric vein then united with the splenic vein to become the hepatic portal vein. Awareness of this uncommon anatomy of the inferior mesenteric vein is important in planning a successful gastrointestinal surgery.
