The most appropriate management is prednisone. Type I autoimmune pancreatitis (AIP) typically presents in older men, with a mean age of onset in the fifth decade of life. This patient has evidence of type 1 AIP based on the presence of three diagnostic criteria: imaging features (focal pancreatic enlargement with a featureless rim and a nondilated pancreatic duct), increased serum IgG4 level, and extrapancreatic organ involvement (sclerosing cholangitis or IgG4-associated cholangitis). Almost all patients (>90%) enter clinical remission in response to glucocorticoids, but relapse is common.

There are no data to support antioxidant treatment for AIP; however, some patients may develop nutritional deficiencies, which warrant treatment.

A biliary metal stent is generally reserved for long-term palliation of malignant biliary strictures and is not required for IgG4-associated cholangitis. IgG4-associated cholangitis typically responds to glucocorticoids, but it may not resolve completely and can relapse. Temporary plastic biliary stents may be required in patients presenting with jaundice who have a dominant stricture, which is not present in this patient.

Surgery is not indicated in this patient but should be considered when the diagnosis is uncertain and pancreatic cancer cannot be excluded.