Annular pancreas detected in adults, diagnosed by endoscopic retrograde cholangiopancreatography: report of four cases.

Four cases of annular pancreas diagnosed by endoscopic retrograde cholangiopancreatography (ERCP) are described and 105 cases of this anomaly in adults in Japan were reviewed. Among 105 cases, abdominal pain was the most frequent symptom. Concerning associated diseases, peptic ulcer was present in 24.8% and pancreatitis in 13.3%. In case 1, duodenal ulcer and pancreatic cyst were noted. Pancreatolithiasis was found in two cases (case 1 and 2). Case 4 presented the clinical features of acute pancreatitis. Out of 105 cases, well-described 26 were divided into six types. The following results were obtained. 1) The most frequent type was that in which the annular duct arose from the duct of Wirsung. 2) The next most frequent type was that in which the main pancreatic duct encircled the duodenum. 3) The other types corresponded to those in which the annular duct arose from the duct of Santorini and the common bile duct. We emphasized that ERCP is the most important procedure to find the characteristic features and to establish the therapeutic strategy in cases of annular pancreas.