Autoimmune pancreatitis

Autoimmune Pancreatitis (AIP) is an increasingly recognized type of chronic pancreatitis that can be difficult to distinguish from pancreatic carcinoma but which responds to treatment with corticosteroids, particularly prednisone. Although autoimmune pancreatitis is quite rare, it constitutes an important clinical problem for both patients and their clinicians: the disease commonly presents itself as a tumorous mass which is diagnostically indistinguishable from pancreatic cancer, a disease that is much more common in addition to being very dangerous. Hence, some patients undergo pancreatic surgery, which is associated to substantial mortality and morbidity, out of the fear by patients and clinicians to undertreat a malignancy. However, surgery is not a good treatment for this condition as AIP responds well to immunosuppressive treatment. There are two categories of AIP: Type 1 and Type 2, each with distinct clinical profiles. Type 1 AIP is now regarded as a manifestation of IgG4-related disease, and those affected have tended to be older and to have a high relapse rate. Type 1 pancreatitis, is as such as manifestation of IgG4 disease, which may also affect bile ducts in the liver, salivary glands, kidneys and lymph nodes. Type 2 AIP seems to affect only the pancreas, although about one-third of people with type 2 AIP have associated inflammatory bowel disease. AIP occurring in association with an autoimmune disorder has been referred to as "secondary" or "syndromic" AIP. AIP does not affect long-term survival. Autoimmune pancreatitis may cause a variety of symptoms and signs, which include pancreatic and biliary (bile duct) manifestations, as well as systemic effects of the disease. Two-thirds of patients present with either painless jaundice due to bile duct obstruction or a "mass" in the head of the pancreas, mimicking carcinoma. As such, a thorough evaluation to rule out cancer is important in cases of suspected AIP. Type 1 AIP typically presents in a 60–70-year-old male with painless jaundice.