Autoimmune pancreatitis: pathologic subtypes and their implications for its diagnosis.

Autoimmune pancreatitis (AIP) is a rare but treatable form of pancreatic disease that is being increasingly recognized worldwide. The diagnosis of AIP remains a clinical challenge and the difficulty is compounded by the fact that there are no internationally agreed on diagnostic criteria for AIP. One of the reasons for the lack of consensus on diagnostic criteria could be that the term "AIP" likely refers to more than one distinct disease or subtype. This may explain the divide between European and other diagnostic criteria. Recent insights into AIP subtypes should help develop an evidence-based consensus on diagnostic criteria for the disease.