Case Report
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Mar 7, 2015; 21(9): 2820-2825
Published online Mar 7, 2015. doi: 10.3748/wjg.v21.i9.2820
Pancreatic intraductal papillary mucinous neoplasm in a patient with Lynch syndrome
Meghan R Flanagan, Arjun Jayaraj, Wei Xiong, Matthew M Yeh, Wendy H Raskind, Venu G Pillarisetty
Meghan R Flanagan, Arjun Jayaraj, Venu G Pillarisetty, Department of Surgery, University of Washington Medical Center, University of Washington, Seattle, WA 98195, United States
Wei Xiong, Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Vancouver, BC V6Z 1Y6, Canada
Matthew M Yeh, Department of Pathology, University of Washington Medical Center, University of Washington, Seattle, WA 98195, United States
Wendy H Raskind, Departments of Medicine/Medical Genetics and Pyschiatry and Behavioral Sciences, University of Washington Medical Center, University of Washington, Seattle, WA 98195, United States
Author contributions: Xiong W and Yeh MM carried out molecular genetic studies; Flanagan MR, Jayaraj A and Pillarisetty VG conceived of the study and drafted the manuscript; Raskind WH was involved in literature review and critical revision of the manuscript; all authors read and approved the final manuscript.
Supported by University of Washington Department of Surgery, Seattle, WA.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (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/
Correspondence to: Venu G Pillarisetty, MD, Assistant Professor, Department of Surgery, University of Washington Medical Center, University of Washington, 1959 NE Pacific St. Box 356410, Seattle, WA 98195, United States. vgp@uw.edu
Telephone: +1-206-6164924 Fax: +1-206-6168136
Received: August 5, 2014
Peer-review started: August 6, 2014
First decision: September 15, 2014
Revised: October 18, 2014
Accepted: December 1, 2014
Article in press: December 1, 2014
Published online: March 7, 2015
Abstract

Intraductal papillary mucinous neoplasm (IPMN) is a mucin-producing epithelial neoplasm that carries a risk of progression to invasive pancreatic ductal adenocarcinoma. Lynch syndrome is an autosomal dominant condition caused by germline mutations in mismatch repair genes such as MSH2 that lead to microsatellite instability and increased risk of tumor formation. Although families with Lynch syndrome have an increased risk of pancreatic cancer, a clear connection between Lynch syndrome and IPMN has not been drawn. We present a report of a 58 year-old Caucasian woman with multiple cancers and a germline mutation of MSH2 consistent with Lynch syndrome. A screening abdominal computed tomography scan revealed a dilated main pancreatic duct and cystic ductular structure in the uncinate process that were consistent with IPMN of the main pancreatic duct on excision. Immunohistochemistry and polymerase chain reaction of the patient’s pancreas specimen did not reveal microsatellite instability or mismatch repair gene loss of expression or function. Our findings may be explained by the fact that loss of mismatch repair function and microsatellite instability is a late event in neoplastic transformation. Given the relative rarity of main duct IPMN, its appearance in the setting of somatic MSH2 mutation suggests that IPMN may fit into the constellation of Lynch syndrome related malignancies.

Keywords: Intraductal papillary mucinous neoplasm, Pancreatic cancer, Hereditary nonpolyposis colorectal cancer, Lynch syndrome, MSH2, Microsatellite instability

Core tip: Intraductal papillary mucinous neoplasms (IPMN) are now recognized as important precursor lesions to pancreatic cancer. Although there have been reports linking pancreatic cancer and familial cancer syndromes, only one previous case report has described IPMN in a patient with Lynch syndrome. Our case is a main duct IPMN that contained only low-grade dysplasia and no microsatellite instability despite the presence of a germline MSH2 mutation. Mismatch repair (MMR) gene mutations may be involved in the neoplastic changes that drive the development of IPMN; however, changes in MMR function may not be detectable in the setting of low-grade neoplasia.