Is autoimmune pancreatitis a risk factor for pancreatic cancer?

Immunoglobulin G4-associated cholangitis: clinical profile and response to therapy

BACKGROUND & AIMS

Immunoglobulin (Ig)G4-associated cholangitis (IAC) is the biliary manifestation of a steroid-responsive multisystem fibroinflammatory disorder in which affected organs have a characteristic lymphoplasmacytic infiltrate rich in IgG4-positive cells. We describe clinical features, treatment response, and predictors of relapse in IAC and compare relapse rates in IAC with intrapancreatic vs proximal bile duct strictures.

METHODS

We reviewed clinical, serologic, and imaging characteristics and treatment response in 53 IAC patients.

RESULTS

IAC patients generally were older (mean age, 62 y) men (85%), presenting with obstructive jaundice (77%) associated with autoimmune pancreatitis (92%), increased serum IgG4 levels (74%), and abundant IgG4-positive cells in bile duct biopsy specimens (88%). At presentation, biliary strictures were confined to the intrapancreatic bile duct in 51%; the proximal extrahepatic/intrahepatic ducts were involved in 49%. Initial presentation was treated with steroids (n = 30; median follow-up period, 29.5 months), surgical resection (n = 18; median follow-up period, 58 months), or was conservative (n = 5; median follow-up period, 35 months). Relapses occurred in 53% after steroid withdrawal; 44% relapsed after surgery and were treated with steroids. The presence of proximal extrahepatic/intrahepatic strictures was predictive of relapse. Steroid therapy normalized liver enzyme levels in 61%; biliary stents could be removed in 17 of 18 patients. Fifteen patients treated with steroids for relapse after steroid withdrawal responded; 7 patients on additional immunomodulatory drugs remain in steroid-free remission (median follow-up period, 6 months).

CONCLUSIONS

IAC should be suspected in unexplained biliary strictures associated with increased serum IgG4 and unexplained pancreatic disease. Relapses are common after steroid withdrawal, especially with proximal strictures. The role of immunomodulatory drugs for relapses needs further study.

Early bile duct cancer in a background of sclerosing cholangitis and autoimmune pancreatitis

A 59-year-old man presented with recent onset jaundice. Initial laboratory and radiologic findings suggested autoimmune pancreatitis (AIP) with consequent obstructive jaundice. All serologic markers for AIP were, however, normal. To confirm the histologic finding of AIP and exclude the possibility of cancer at the thickened segment of common bile duct, cholangioscopic examination was performed and bile duct cancer was observed. The resected specimen showed typical features of AIP throughout the entire pancreas and early carcinomatous change on a background of abundant IgG4-positive cells in the common bile duct. Although chronic biliary inflammation and cholestasis are among bile duct cancer risk factors, the cause-and-effect relationship between sclerosing cholangitis and bile duct cancer needs to be determined by further study, as between AIP and pancreatic cancer. Importantly, histologic exclusion of malignancy is another essential step in the diagnosis of AIP and sclerosing cholangitis as malignancy may coexist in bile duct as well as in the pancreas.