Superior mesenteric origin of the proper hepatic artery: embryological and clinical implications

The hepatic arteries are subject to a great deal of anatomical variation, potentially complicating hepatobiliary surgical procedures as well as general gastrointestinal procedures that involve foregut and midgut structures. We report a case of a rare variant of the proper hepatic artery discovered during dissection of an 84-year-old male cadaver. In this individual, the common hepatic artery was absent and the proper hepatic artery was replaced directly to the superior mesenteric artery. The gastroduodenal artery and the right inferior phrenic artery took origin from the celiac trunk. In addition, there was no identifiable right gastric artery. The celiac trunk gave off three branches: the splenic, left gastric, and gastroduodenal arteries. The entire arterial blood supply to the liver, therefore, was derived from the superior mesenteric artery. Patterns of regression of the ventral branches and the partial disappearance of the ventral anastomotic arteries during embryonic development play a major role in the variations of the gut arteries. An intraoperative encounter with this particular variant carries a significant risk of iatrogenic injury with potentially devastating ischemia and necrotic results. Accurate depiction and definition of the hepatic arterial anatomy are crucial. Variations like the one described here underscore the importance of pre-operative imaging and knowledge of the embryological origins of variation.