Abstracts: CLINICAL VIGNETTES
Case: A 28-year old Caucasian male presented with epigastric pain, nausea, and vomiting. There was no history of NSAID use. He had normal LFTs, amylase and lipase. EGD revealed an ulcerated mass/narrowing in the descending duodenum. Biopsies showed duodenitis, H. pylori negative. An UGI series showed a focal constriction in the descending duodenum. Abdominal CT showed an incomplete annular pancreas (AP) encircling the anterior and lateral aspect of the descending duodenum with narrowing of the duodenal lumen. The patient's symptoms initially responded to high dose PPI, but recurred four months later. Repeat EGD showed severe narrowing of the descending duodenum. The patient underwent gastrojejunostomy with relief of the symptoms. Repeat EGD revealed healed ulcers/erosions.
Discussion: AP is a rare congenital anomaly (incidence 1:20,000) characterized by a ring of pancreatic tissue surrounding the descending duodenum. It results from failure of the ventral anlage of the pancreas to rotate with the duodenum. There are two main etiologic theories: (1) Lecco's Theory – adherence of the ventral bud to the duodenal wall prior to rotation results in its persistence and encirclement of the duodenum, and (2) Baldwin's theory – persistence and enlargement of the ventral bud. It can present at any age, including infants. Most adults present between 20 and 50 years of age. Most are asymptomatic. Presenting symptoms include abdominal pain, nausea, postprandial fullness, vomiting, UGI bleeding (from peptic ulcer), acute or chronic pancreatitis, and rarely biliary obstruction. 15% of adults with AP have duodenal stenosis. 33% have PUD. PUD is believed to be due to prolonged stasis of antral contents. The treatment is bypass surgery of the annulus, by duodenojejunostomy, duodenoduodenostomy, or a gastrojejunostomy.
Conclusion: This is an unusual presentation of AP in adulthood as a DU and constriction refractory to PPI therapy, which responded to gastrojejunostomy. AP should be strongly considered in the differential diagnosis of a benign idiopathic PUD in the descending duodenum associated with severe focal duodenal narrowing, and refractory to PPI therapy. AP should be excluded by appropriate imaging studies.[figure1]