- Second most common congenital anomaly
- Failure of normal rotation during development
- Pancreas partially or completely encircles duodenum
- Sometimes causes symptomatic duodenal narrowing
- Barium studies show narrowing at level of major papilla
- Quite often asymptomatic
- CT, MRI shows the tissue around second part of duodenum
- ERCP or MRCP will show the duct encircling the duodenum