Title: CLINICAL DIAGNOSTIC CRITERIA OF AUTOIMMUNE PANCREATITIS
Abstract: The "clinical diagnostic criteria of autoimmune pancreatitis: revised proposal, 2006" are, (1) histological diagnosis with a tiny biopsy specimen and (2) no use of special stains other than routine ones. The histology of autoimmune pancreatitis in Japan corresponds to so-called "lymphoplasmacytic sclerosing pancreatitis": periductal lymphoplasmacytic infiltration, inter/intra lobular fibrosis (storiform fibrosis), IgG4-positive plasma cells (IgG-P), and obliterative phlebitis. The diagnostic criteria of autoimmune pancreatitis in Mayo Clinic are different from ours in that immunostaining for IgG4 is often required as well as a larger biopsy specimen. Korean criteria are similar to ours, but the biopsy procedures are different. A big challenge for pancreatic biopsy must be how to get a diagnostic, representative specimen of the entire histology. Many IgG4-Ps in storiform fibrosis are "diagnostic" and even a tiny specimen can be diagnostic if it includes an adequate amount of lesion.