Middle mesenteric artery: an anomalous origin of a middle colic artery.

A case of anomalous mesenteric artery is reported. The artery was incidentally cannulated during angiography of a patient with a left renal tumor. It arose from the abdominal aorta between the superior and inferior mesenteric arteries. The artery then ascended directly upwards from its origin and supplied the transverse colon replacing the middle colic branch of the superior mesenteric artery. The anomaly must be a result of a anomalous concentration of unpaired visceral arteries in the developing embryo. This type of anomaly is very rare and it would be appropriate to name the artery the middle mesenteric artery.