Duodenum inversum: a report and review of the literature.

Duodenum inversum is a rare congenital malformation defined by a duodenum which travels superiorly and then posteriorly prior to crossing the midline above the pancreas. It is often confused with other, more common, anomalies of intestinal rotation. We present a case of duodenum inversum diagnosed incidentally in a one-month old infant with Trisomy 21 during evaluation for reflux disease. Due to an inability to definitively rule out malrotation, the diagnosis was confirmed with a diagnostic laparoscopy. We discuss available literature concerning this rare anatomic anomaly as well as provide recommendations for diagnosis and treatment.