The Difficulty of the Definition of Igg4 Related Sclerosing Cholangitis – Should Cases with Bile Duct Stricture Limited to Intrapancreatic Area be Included in this Disease?

IgG4-related sclerosing cholangitis (IgG4-SC) is a characteristic type of sclerosing cholangitis which may be regarded as a biliary lesion of IgG4 related disease [1]. The disease name of IgG4-SC is now well known among gastroenterologists, however, there is a confusing problem about its diagnosis. That is, how to deal with intrapancreatic biliary stricture is very difficult. It is known that IgG4-SC is often associated with autoimmune pancreatitis (AIP). As pancreatic head edema may cause the compression of intrapancreatic bile duct, such lesion can be regarded as a part of pancreatic lesion [2,3]. On the other hand, there is another opinion that it should be also regarded as a biliary lesion because biliary wall thickening is often observed in such patients [4].