Question: A 68 year old female is hospitalized with a sclerosing cholangitis like illness and was found to have involvement in the pancreas (narrow pancreatic duct, enlarged head with questionable mass). You of course know to order an IgG4 level and sure enough it is dramatically elevated. She is started on a course of steroids. You are asked what other organs can become involved with IgG4 depositional disease if it goes untreated.
A. facial skin
Answer: Autoimmune pancreatitis is a bit of a misnomer for IgG4-related sclerosing disease. Many other organs can be involved as the immunoglobulin is deposited systemically. In this case, the intrahepatic biliary tree presented like PSC; its strictures should resolve with steroids. Any pancreatic endocrine or exocrine dysfunction may also resolve. Whenever entertaining (or making) a diagnosis of PSC, IgG4 disease should be ruled out because the treatment is different and very effective!
Other organs commonly involved with this disease include lymph nodes, salivary glands and kidneys. Retroperitoneal fibrosis occurs in nearly 10% of cases, according to the study below (click on link). The tongue, heart and facial skin are not thought to be involved with this disease.