<unk>  is a rare condition in which the second part of the duodenum is surrounded by a ring of<unk> ic tissue continuous with the head of the<unk> . This portion of the<unk>  can constrict the duodenum and block or impair the flow of food to the rest of the intestines.  It occurs in 1 out of 12,000 to 15,000 newborns.
Annular pancreas
Accessory pancreas
Pancreas divisum
Bile duct cyst
Splenic cyst
Duodenal diverticulum
Gallbladder volvulus
Hartnup Disease