Diffuse pancreatic adenocarcinoma identified in an adult with annular pancreas.

Annular pancreas is a congenital anomaly resulting from malrotation of the pancreatic ventral bud. Although annular pancreas in the adult is rare, it may be recognized with increased frequency as a result of more liberal use of pancreatic imaging studies in patients with chronic abdominal pain and suspected chronic pancreatitis. Malignancy in the setting of annular pancreas is an uncommon event that has been reported previously but has almost always been related to the annular (ventral) segment. We report an interesting case in which pancreatic adenocarcinoma diffusely involving the dorsal (nonannular) segment presented in a middle-aged female patient. This unusual presentation points out the importance of considering neoplasia as part of the differential diagnosis and the possibility of pancreatic pathology in the dorsal, nonannular segment when there is no obvious duodenal or biliary obstruction involving the annular ventral segment.