Extrapancreatic manifestations in autoimmune pancreatitis.

It is increasingly recognized that organs beyond the pancreas may be clinically involved in patients with autoimmune pancreatitis (AIP). Other gastrointestinal sites (such as the extrapancreatic biliary tree, liver, and ampulla) appear particularly affected, but involvement of many other organs (including kidneys, lungs, retroperitoneum, and brain) is increasingly reported. A similar histological lesion, characterized by an IgG4-positive lymphoplasmacytic infiltrate, affects both the pancreas and extrapancreatic tissues, strongly suggesting an aetiopathogenic link. In this review we discuss the clinical presentation and disease course, diagnostic features, and management of extrapancreatic involvement in AIP.