General Principles

• Chronic pancreatitis represents inflammation, fibrosis, and atrophy of acinar cells resulting from recurrent acute or chronic inflammation of the pancreas.
• Most commonly seen with chronic alcohol abuse, it can also result from dyslipidemia, hypercalcemia, autoimmune disease, and exposure to various toxins. An inherited form (hereditary pancreatitis) is rarely seen; this can be associated with mutations in genes encoding cationic trypsinogen (PRSS1) or pancreatic secretory trypsin inhibitor (SPINK1) (Gastroenterology 2007;132:1557  [PMID:17466744]).
• Autoimmune pancreatitis (AIP) represents an increasingly recognized subtype of chronic pancreatitis characterized by infiltration of IgG4-positive plasma cells in a classically sausage-shaped pancreas. AIP can be difficult to distinguish from pancreatic cancer on CT, but typically features diffuse narrowing of the main pancreatic duct without dilation. Initial treatment has traditionally been with high-dose steroids, although low-dose steroids may be similarly effective (Pancreas 2014;43:261  [PMID:24518506]). Relapses may occur in the pancreas or biliary tree, although retreatment with steroids is effective at inducing remission (Gut 2013;62:1771  [PMID:23232048]).