Autoimmune pancreatitis: pathological findings.

In recent years, autoimmune pancreatitis has been established as a special type of chronic pancreatitis. It is characterized by its histopathological and immunological features. The morphological hallmarks are periductal infiltration by lymphocytes and plasma cells and granulocytic epithelial lesions with consequent destruction of the duct epithelium and venulitis. Autoimmune pancreatitis has therefore also been called lymphoplasmacytic sclerosing pancreatitis, duct-destructive chronic pancreatitis, or sclerosing pancreatitis. Autoimmune pancreatitis most commonly involves the head of the pancreas and the distal bile duct. Occasionally, masses are formed and it has been described as an inflammatory myofibroblastic tumor.