Multimodality imaging of pancreatic and biliary congenital anomalies.

A wide spectrum of anomalies of the pancreas, the pancreatic ductal system, and the biliary tree are commonly encountered at radiologic evaluation. These anomalies may simulate various neoplastic, inflammatory, and posttraumatic conditions and should be part of the differential diagnosis for a variety of abnormalities found at diagnostic imaging. Anatomic variants, developmental anomalies (eg, pancreas divisum, annular pancreas, ectopic pancreas, pancreatic agenesis and hypoplasia), and congenital diseases (congenital pancreatic cysts, von Hippel-Lindau disease, choledochal cysts), in addition to potential imaging pitfalls (uneven distribution of fat, "pseudomasses"), can all pose a diagnostic challenge for the radiologist. Familiarity with these anomalies, the imaging techniques available for their study, and their variable imaging manifestations is necessary for differentiating them from other biliary and pancreatic conditions. A basic understanding of the embryologic development and normal anatomy of the pancreas and biliary tree is also essential for identifying these anomalies.