Histopathologic characteristics of autoimmune pancreatitis based on comparison with chronic pancreatitis.

OBJECTIVES

To clarify the histopathologic characteristics of autoimmune pancreatitis (AIP), based on comparison with both chronic alcoholic pancreatitis (CAP) and chronic obstructive pancreatitis (COP).

METHODS

Three AIP patients, 17 CAP patients, and 19 COP patients were studied histopathologically.

RESULTS

There was a dense lymphoplasmacytic infiltrate, especially within and around the pancreatic ducts, and fibrosis associated with AIP, while there was fibrosis accompanied by mild inflammatory infiltration in both CAP and COP. Inter- and intralobular fibrosis admixed with acinar atrophy was observed in both AIP and COP, while interlobular fibrosis combined with a "cirrhosis-like" appearance was found in CAP. Obliterative phlebitis was found in AIP, while thrombosis of the splenic vein was exhibited in CAP.

CONCLUSION

Autoimmune pancreatitis was histologically characterized by dense lymphoplasmacytic infiltrate combined with fibrosis, acinar atrophy, obliterative phlebitis, and ductal involvement.