IgG4-associated cholecystitis: Another clue in the diagnosis of autoimmune pancreatitis

Purpose: Autoimmune pancreatitis (AIP) is the pancreatic manifestation of IgG4-associated systemic disease (ISD). Criteria for diagnosis of AIP include recognition of extra-pancreatic organ involvement. Because the diagnosis of AIP can be challenging, even for experts, it is important for clinicians to recognize other target organ damage in this disease. Typical gallbladder findings in AIP have been increasingly recognized. Because cholecystectomy is common in the community, the availability of previous tissue from the gallbladder can provide an important supportive clue in the diagnosis of AIP. The objective of this review is to examine the literature on common gallbladder pathology findings in AIP, and discuss their clinical utility. Results: Gallbladder involvement in AIP seems to be common. Transmural lymphoplasmacytic inflammatory infiltrates, extramural inflammatory nodules, the presence of tissue eosinophilia, phlebitis, and increased tissue IgG4 are all seen more frequently in the gallbladders of patients with AIP. These findings are not 100% specific, because some can be seen in primary sclerosing cholangitis and pancreatic adenocarcinoma. Conclusion: Cholecystectomy for the purpose of diagnosing AIP is not recommended. However, if gallbladder specimens from a previous cholecystectomy are available, an expert review of gallbladder slides with IgG4 immunostaining may help to provide additional criteria for diagnosis of autoimmune pancreatitis.