Retrospective Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jul 21, 2021; 27(27): 4429-4440
Published online Jul 21, 2021. doi: 10.3748/wjg.v27.i27.4429
Multifocal autoimmune pancreatitis: A retrospective study in a single tertiary center of 26 patients with a 20-year literature review
Xin-Ming Huang, Zhen-Shan Shi, Cheng-Le Ma
Xin-Ming Huang, Zhen-Shan Shi, Cheng-Le Ma, Department of Radiology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian Province, China
Xin-Ming Huang, Department of Radiology, Fujian Medical University Union Hospital, Fuzhou 350005, Fujian Province, China
Author contributions: Huang XM did the imaging analysis and supervised all the procedures of this study; Shi ZS designed this study, wrote the main manuscript, revised the manuscript, and did statistical analysis; Shi ZS and Ma CL performed dynamic contrast enhanced-computed tomography scanning; Huang XM and Ma CL contributed equally.
Supported by the Science and Technology Committee of Fujian Province, No. 2016Y0039; and the Subsidizing Provincial Universities Project of Educational Commission of Fujian Province, No. JK2017019.
Institutional review board statement: This retrospective study was reviewed and approved by the Institutional Review Board of the First Affiliated Hospital of Fujian Medical University (Fuzhou, China), and written informed consent from patients was waived.
Informed consent statement: The study has obtained after each patient agreed to treatment by written consent.
Conflict-of-interest statement: There are no conflicts of interest related to this study.
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:
Corresponding author: Zhen-Shan Shi, MD, Chief Doctor, Department of Radiology, The First Affiliated Hospital of Fujian Medical University, No. 20 Cha-Zhong Road, Fuzhou 350005, Fujian Province, China.
Received: January 28, 2021
Peer-review started: January 28, 2021
First decision: February 24, 2021
Revised: February 28, 2021
Accepted: April 25, 2021
Article in press: April 25, 2021
Published online: July 21, 2021
Research background

Multifocal-type autoimmune pancreatitis (AIP), sometimes forming multiple pancreatic masses, is frequently misdiagnosed as pancreatic malignancy in routine clinical practice. It is critical to know the imaging features of multifocal-type AIP to prevent misdiagnosis and unnecessary surgery. To the best of our knowledge, there have been no studies evaluating the value of diffusionweighted imaging (DWI), axial fat-suppressed T1 weighted image (T1WI), and dynamic contrast enhanced-computed tomography (DCE-CT) in detecting the lesions of multifocal-type AIP.

Research motivation

The key issue is whether CT and magnetic resonance imaging features of multifocal-type AIP can help definitively distinguish from pancreatic ductal adenocarcinoma (PDA) and whether there is an optimal modality to identify pancreatic lesions as correctly as possible. The results will provide important information on the diagnostic performances of DWI, axial fat-suppressed T1WI, and DCE-CT and the key imaging features for differentiating multifocal-type AIP from PDA.

Research objectives

We aimed to clarify the exact prevalence and radiological findings of multifocal AIP in our cohorts and compare the sensitivity of DWI, axial fat-suppressed T1WI, and DCE-CT for detecting AIP lesions. We also compared radiological features between multifocal AIP and PDA with several key imaging landmarks.

Research methods

Twenty-six patients with proven multifocal AIP were retrospectively included. Two blinded independent radiologists rated their confidence level in detecting the lesions on a 5-point scale and assessed the diagnostic performance of DWI, axial fat-suppressed T1WI, and DCE-CT. CT and magnetic resonance images of multifocal AIP were systematically reviewed for typical imaging findings and compared with the key imaging features of PDA.

Research results

Among 118 patients with AIP, 26 (22.0%) had multiple lesions (56 lesions). Ulcerative colitis was associated with multifocal AIP in 7.7% (2/26) of patients, and Crohn’s disease was associated in 15.3% (4/26) of patients. In multifocal AIP, multiple lesions, delayed homogeneous enhancement, multifocal strictures of main pancreatic duct, capsule-like rim, lower apparent diffusion coefficient values, and elevated serum Ig4 Level were observed significantly more frequently than in PDA, whereas the presence of capsule-like rim in multifocal-type AIP was lower in frequency than total AIP. Of these lesions of multifocal AIP, DWI detected 89.3% (50/56) and 82.1% (46/56) by the senior and junior radiologist, respectively.

Research conclusions

Multifocal AIP is not as rare as previously thought and was seen in 22% of our patients. The diagnostic performance of DWI for detecting multifocal AIP was best followed by axial fat-suppressed T1WI and DCE-CT.

Research perspectives

Larger and longer term prospective studies to investigate the important radiological findings for differential diagnosis between multifocal AIP and PDA should be performed in future studies.