Brief Article
Copyright ©2012 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. May 7, 2012; 18(17): 2099-2104
Published online May 7, 2012. doi: 10.3748/wjg.v18.i17.2099
Differences between diffuse and focal autoimmune pancreatitis
Taku Tabata, Terumi Kamisawa, Kensuke Takuma, Seiichi Hara, Sawako Kuruma, Yoshihiko Inaba
Taku Tabata, Terumi Kamisawa, Kensuke Takuma, Seiichi Hara, Sawako Kuruma, Yoshihiko Inaba, Department of Internal Medicine, Tokyo Metropolitan Komagome Hospital, 3-18-22 Honkomagome, Bunkyo-ku, Tokyo 113-8677, Japan
Author contributions: Tabata T and Kamisawa T contributed equally to this work, analyzed the data and wrote the manuscript; Takuma K, Hara S, Kuruma S and Inaba Y collected the data.
Supported by The Research Committee of Intractable Pancreatic Diseases (Principal investigator; Tooru Shimosegawa) provided by the Ministry of Health, Labour and Welfare of Japan
Correspondence to: Terumi Kamisawa, MD, PhD, Department of Internal Medicine, Tokyo Metropolitan Komagome Hospital, 3-18-22 Honkomagome, Bunkyo-ku, Tokyo 113-8677, Japan. kamisawa@cick.jp
Telephone: +81-3-38232101 Fax: +81-3-38241552
Received: May 31, 2011
Revised: August 19, 2011
Accepted: August 27, 2011
Published online: May 7, 2012
Abstract

AIM: To investigate differences in clinical features between diffuse- and focal-type autoimmune pancreatitis (AIP).

METHODS: Based on radiological findings by computed tomography and/or magnetic resonance imaging, we divided 67 AIP patients into diffuse type (D type) and focal type (F type). We further divided F type into head type (H type) and body and/or tail type (B/T type) according to the location of enlargement. Finally, we classified the 67 AIP patients into three groups: D type, H type and B/T type. We compared the three types of AIP in terms of clinical, laboratory, radiological, functional and histological findings and clinical course.

RESULTS: There were 34 patients with D-type, 19 with H-type and 14 with B/T-type AIP. Although obstructive jaundice was frequently detected in D-type patients (88%) and H-type patients (68%), no B/T-type patients showed jaundice as an initial symptom (P < 0.001). There were no differences in frequency of abdominal pain, but acute pancreatitis was associated more frequently in B/T-type patients (36%) than in D-type patients (3%) (P = 0.017). Serum immunoglobulin G (IgG)4 levels were significantly higher in D-type patients (median 309 mg/dL) than in B/T-type patients (133.5 mg/dL) (P = 0.042). Serum amylase levels in B/T-type patients (median: 114 IU/L) were significantly greater than in H-type patients (72 IU/L) (P = 0.049). Lymphoplasmacytic sclerosing pancreatitis (LPSP) was histologically confirmed in 6 D-type, 7 H-type and 4 B/T-type patients; idiopathic duct-centric pancreatitis was observed in no patients. Marked fibrosis and abundant infiltration of CD20-positive B lymphocytes with few IgG4-positive plasma cells were detected in 2 B/T-type patients. Steroid therapy was effective in all 50 patients (31 D type, 13 H type and 6 B/T type). Although AIP relapsed during tapering or after stopping steroids in 3 D-type and 3 H-type patients, no patients relapsed in B/T type. During follow-up, radiological features of 6 B/T-type patients were not changed and 1 B/T-type patient improved naturally.

CONCLUSION: Clinical features of H-type AIP were similar to those of D-type, but B/T-type differed from D and H types. B/T-type may involve diseases other than LPSP.

Keywords: Autoimmune pancreatitis, Immunoglobulin G 4, Lymphoplasmacytic sclerosing pancreatitis