Case Presentation: A 75-year-old male with a history of HTN, CVA, and smoking, presented for follow up evaluation of his abdominal aortic aneurism. CT angiography with run-off was performed and revealed a choledochal cyst, common bile duct dilation, and a mass in the head of the pancreas with air bubbles, which represented a type III choledochal cyst. This study demonstrated rapid development of the cyst when compared to CT from three months prior. Retrospective imaging review showed that it may have been present in 2013, although much smaller. The patient denied nausea, vomiting, abdominal pain, diarrhea, constipation, and changes in diet or weight. Liver chemistries were unremarkable except for elevated triglycerides up to 700s over the past 4 years.
Abdominal MRI was performed for further evaluation and showed improving mild extrahepatic biliary ductal dilatation. The common bile duct measured up to 1 cm, with interval decrease in size of 1.5 x 1.1 cm, and a complex-appearing intrapancreatic/periampullary duodenal diverticulum (PAD) containing inspissated material causing mild biliary dilatation.
Discussion:
Diverticula of the gastrointestinal tract are outpouchings of all or part of the intestinal wall which can occur anywhere throughout the alimentary tract. They may be found in the colon and less commonly in the duodenum. PAD are the most common type of duodenal diverticula and they develop within 2-3cm from the ampulla of Vater. PAD are detected in up to 27% of patients undergoing upper gastrointestinal tract evaluation.
PAD tend to develop in middle age and may be the result of disordered duodenal motility.
Most PAD are asymptomatic, but complications can occur in about 5% of cases. Complications include bleeding, perforation, diverticulitis, pancreatitis, choledocholithiasis, cholangitis, jaundice, enterolith, or bezoar formation, and intestinal obstruction.
Sudden increase in size in PAD may mimic malignant disease and further imaging including CT and magnetic retrograde cholangiopancreatography can be done,which demonstrate thin-walled cavitary lesions situated on the medial wall of the 2nd portion of the duodenum and may contain gas.
A side-viewing endoscope with endoscopic retrograde cholangiopancreatography have a higher sensitive and specificity for diagnosis of PAD.
Prior imaging demonstrating fluctuating size of PAD with increasing and decreasing size can support the benign entity of this disease.
Conclusions: Periampullary diverticula (PAD) are an interesting finding of the gastrointestinal tract that have been linked to pancreaticobiliary complications in rare cases. Clinicians must consider differential diagnoses for PAD, as it may mimic pancreatic abscesses, metastatic lymph nodes, and even malignancy due to rapid increase in cyst size.