The investigation of unexplained biliary dilatation.

The investigation of biliary dilatation forms a routine part of gastroenterology practice. In developed countries, biliary dilatation is usually the result of obstruction of bile flow by either stones or mitotic lesions of the pancreas or biliary tree, and standard radiologic and endoscopic techniques are used to identify and relieve the obstruction. In the absence of an obvious cause, however, the investigation and management of biliary dilatation can prove challenging, particularly while trying to minimize invasive studies. This review examines factors thought to influence bile duct size in the absence of obvious obstructing pathology and looks at some causes of biliary dilatation that are unusual and potentially difficult to diagnose.