Annular Pancreas Causing Duodenal and Biliary Obstruction

Abstract

Purpose: The incidence of annular pancreas is about 1:20,000. It is a congenital abnormality of pancreatic tissue that circles the duodenum and is of ventral pancreas in origin. Its most common presentation is of duodenal stenosis, peptic ulceration, and pancreatitis. In this rare case we will present a patient who presents with both duodenal obstruction and biliary obstruction. Methods: Case: A 42 y/o male with past medical history significant for diabetes and hypertension presents with a three day history of intractable nausea and vomiting. On admission patient was in acute renal failure with a creatinine of 1.7. He was also jaundiced with a total bilirubin of 12.2 mg per dL and a conjugated fraction of 9 mg per dL. Other laboratory testing revealed an AST of 149 U/L, an ALT of179 U/L, an Alkaline Phosphatase of 103 U/L, and an albumin of 2.2 mg per d/L. An abdominal series revealed air fluid levels in the distal stomach and the fundus. A CT scan was then performed that revealed a 1.5 cm common bile duct, a 7 mm pancreatic duct, a dilated stomach with no filling of contrast into the duodenum. No mention was made of annular pancreas. An EGD was performed to evaluate for gastric outlet obstruction. This revealed a massively dilated duodenum with a stenotic area in the second portion of the duodenum proximal to the ampulla. This stenosis made ERCP impossible. Annular pancreas was suspected at this time and the patient was taken to surgery for a bypass operation. Results: Discussion: Annular pancreas has a bimodal presentation, the first peak being in neonates and the second being in the fourth and fifth decades of life. Trisomy 21, duodenal atresia, tracheoesophageal fistula, and cardiorenal abnormalities have an association with annular pancreas. Because the pancreatic tissue often extends into the duodenal wall and may contain a large pancreatic duct, symptomatic cases of annular pancreas are best treated by surgical bypass rather than surgical resection. Conclusions: This case illustrates the importance of suspecting annular pancreas when patients present with either duodenal stenosis or biliary obstruction even if ct scan findings are negative.