Retrospective Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Nov 14, 2021; 27(42): 7376-7386
Published online Nov 14, 2021. doi: 10.3748/wjg.v27.i42.7376
Endoscopic ultrasound features of autoimmune pancreatitis: The typical findings and chronic pancreatitis changes
Sheng-Yu Zhang, Yun-Lu Feng, Long Zou, Xi Wu, Tao Guo, Qing-Wei Jiang, Qiang Wang, Ya-Min Lai, Shou-Jiang Tang, Ai-Ming Yang
Sheng-Yu Zhang, Yun-Lu Feng, Long Zou, Xi Wu, Tao Guo, Qing-Wei Jiang, Qiang Wang, Ya-Min Lai, Ai-Ming Yang, Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China
Shou-Jiang Tang, Division of Digestive Disease, Department of Medicine, University of Mississippi Medical Center, Jackson, MS 39216, United States
Author contributions: Zhang SY and Feng YL contributed equally to this work and should be considered as co-first authors; Zhang SY, Wu X, Guo T, Tang SJ and Yang AM designed the study; Zhang SY and Feng YL collected and analyzed the data; Zou L and Lai YM collected the clinical information; Zou L collected the endoscopic images; Wu X, Guo T, Jiang QW and Wang Q collected the images; Zhang SY, Feng YL, Wang Q and Tang SJ analyzed the images; Zhang SY wrote the manuscript; Feng YL and Tang SJ revised the manuscript; Yang AM approved the final version of the manuscript.
Supported by Beijing Science and Technology Program, No. Z181100001618013; Peking Union Medical College Education Reform Program, No. 2019zlgc0116.
Institutional review board statement: The study was reviewed and approved by the Ethics Committee of Peking Union Medical College Hospital (approval number S-K1613).
Conflict-of-interest statement: The authors declare no conflicts of interest for this article.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Ai-Ming Yang, MD, Director, Professor, Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, No. 9 Dongdan Santiao, Dongcheng District, Beijing 100730, China. yangam2020@126.com
Received: June 13, 2021
Peer-review started: June 13, 2021
First decision: July 14, 2021
Revised: July 27, 2021
Accepted: October 25, 2021
Article in press: October 25, 2021
Published online: November 14, 2021
Processing time: 149 Days and 18.9 Hours
ARTICLE HIGHLIGHTS
Research background

Few studies have fully described the endoscopic ultrasound (EUS) features of newly diagnosed autoimmune pancreatitis (AIP) involving both typical findings and chronic pancreatitis (CP) features. The typical EUS findings are prevalent in diffuse AIP but may not be as common for the focal type, and the differences between diffuse and focal AIP need to be specified. The EUS typical features of AIP (especially the cholangiopathy-like features) can help to differentiate diffuse AIP from classic CP and differentiate focal AIP from pancreatic cancer.

Research motivation

This is the largest single center retrospective study demonstrating EUS features in newly diagnosed type 1 AIP patients that not only describes the typical findings and the CP features of AIP but also figures out the difference between the diffuse and focal types.

Research objectives

The authors conducted this single center retrospective study for a detailed description of the EUS features of newly diagnosed AIP patients and demonstration of the difference between diffuse and focal AIP, and we tried to compare the CP change level in both groups via the Rosemont criteria based on all CP features.

Research methods

This retrospective single center study included 285 patients of newly diagnosed type 1 AIP following the international consensus diagnostic criteria, with the EUS procedures accomplished before corticosteroid initiation. We explored the EUS features and compared the typical AIP and CP features between the diffuse and focal AIP cases. The Rosemont criteria were employed for CP features definition and CP change level comparison.

Research results

For the typical AIP features, there were significantly more patients in the diffuse group with bile duct wall thickening and peripancreatic hypoechoic margin. In the multivariate regression analysis for diffuse AIP, we demonstrated the predictors of diffuse AIP: the DHA, bile duct wall thickening and peripancreatic hypoechoic margin (all P < 0.001), which are all typical EUS findings of AIP rather than CP features. For the CP features, there were significantly more patients in the focal group with main pancreatic duct dilation. The cholangitis-like changes were more prevalent in the focal cases with pancreatic head involvement. The CP change level was relatively limited for newly diagnosed AIP cases in the diffuse and focal groups.

Research conclusions

This study demonstrated the EUS features of newly diagnosed AIP and the difference in the typical AIP features and CP features between the diffuse and focal AIP cases on the basis of the largest number of cases. It indicated the relatively limited CP change in newly diagnosed AIP cases via the Rosemont criteria.

Research perspectives

EUS can detect the early parenchymal fibrosis of CP in AIP cases, which changes dynamically after corticosteroid therapy. As the tool for accessing the fibrosis degree of the pancreas, the EUS findings of CP may be used for predicting pancreatic atrophy and diabetes exacerbation, which needs further investigation.