Annular pancreas is a congenital malformation but manifestations can appear in the adult life.
Annulus means a ring of pancreatic tissue around the duodenum. For annular pancreas to be diagnosed, this ring can be complete or incomplete.
Normally the ventral buds of pancreas and dorsal bud fuses together. Non rotation and fusion of these two leads to the formation of annular pancreas. It envelops the 2nd part of duodenum.
Age of presentation
Incidence is equal in both adults and children
Presentation in children is congenital anomalies and duodenal obstruction
Presents in adults as pancreatitis usually in 3rd or 4th decade
Association with other pancreatic conditions
1. Pancreas divisum 35- 40%
2. Chronic pancreatitis 45- 50%
Other GI conditions
Annular pancreas is a possible etiology of congenital duodenal obstruction and is associated with other congenital anomalies such as Down syndrome, duodenal atresia, and imperforate anus.
Of those seen as adults, 75%were seen with pain
22% were diagnosed with pancreatitis
24%) had gastrointestinal (GI) symptoms that included vomiting,
11%had obstructive jaundice and/or abnormal liver function test results.
Ref BG page 869
It is duodenal bypass and not resection of duodenum as duodenum excision can lead to pancreatitis
in children its duodeno - duodenostomy
in adults duodenoduodenostomy which has now replaced duodenojejunostomy