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Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Oncol. Aug 15, 2020; 12(8): 833-849
Published online Aug 15, 2020. doi: 10.4251/wjgo.v12.i8.833
One size does not fit all for pancreatic cancers: A review on rare histologies and therapeutic approaches
Monica Niger, Michele Prisciandaro, Maria Antista, Melissa Anna Teresa Monica, Laura Cattaneo, Natalie Prinzi, Sara Manglaviti, Federico Nichetti, Marta Brambilla, Martina Torchio, Francesca Corti, Sara Pusceddu, Jorgelina Coppa, Vincenzo Mazzaferro, Filippo de Braud, Maria Di Bartolomeo
Monica Niger, Michele Prisciandaro, Maria Antista, Natalie Prinzi, Sara Manglaviti, Federico Nichetti, Marta Brambilla, Martina Torchio, Francesca Corti, Sara Pusceddu, Filippo de Braud, Maria Di Bartolomeo, Medical Oncology Department, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan 20133, Italy
Melissa Anna Teresa Monica, Laura Cattaneo, First Pathology Division, Department of Pathology and Laboratory Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan 20133, Italy
Jorgelina Coppa, Vincenzo Mazzaferro, Hepato-biliary-pancreatic Surgery and Liver Transplantation Department, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan 20133, Italy
Vincenzo Mazzaferro, Filippo de Braud, Università degli studi di Milano, Milan 20133, Italy
Author contributions: Niger M designed and wrote the final version of the manuscript; Antista M, Prisciandaro M, Niger M, Monica MAT, and Cattaneo L were critical for the acquisition of data and drafting the manuscript; Prinzi N, Manglaviti S, Coppa J, Brambilla M, Torchio M, Corti F, Nichetti F, and Pusceddu S contributed to the analysis and interpretation of the literature; Mazzaferro V, de Braud F, and Di Bartolomeo M made critical revisions to the design and gave final approval for the article to be submitted.
Conflict-of-interest statement: The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript.
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: Maria Di Bartolomeo, MD, Doctor, Medical Oncology Department, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Giacomo Venezian 1, Milan 20133, Italy. maria.dibartolomeo@istitutotumori.mi.it
Received: January 31, 2020
Peer-review started: January 31, 2020
First decision: April 18, 2020
Revised: May 1, 2020
Accepted: May 19, 2020
Article in press: May 19, 2020
Published online: August 15, 2020
Processing time: 193 Days and 10.1 Hours
Abstract

Exocrine pancreatic neoplasms represent up to 95% of pancreatic cancers (PCs) and are widely recognized among the most lethal solid cancers, with a very poor 5-year survival rate of 5%-10%. The remaining < 5% of PCs are neuroendocrine tumors that are usually characterized by a better prognosis, with a median overall survival of 3.6 years. The most common type of PC is pancreatic ductal adenocarcinoma (PDAC), which accounts for roughly 85% of all exocrine PCs. However up to 10% of exocrine PCs have rare histotypes, which are still poorly understood. These subtypes can be distinguished from PDAC in terms of pathology, imaging, clinical presentation and prognosis. Additionally, due to their rarity, any knowledge regarding these specific histotypes is mostly based on case reports and a small series of retrospective analyses. Therefore, treatment strategies are generally deduced from those used for PDAC, even if these patients are often excluded or not clearly represented in clinical trials for PDAC. For these reasons, it is essential to collect as much information as possible on the management of PC, as assimilating it with PDAC may lead to the potential mistreatment of these patients. Here, we report the most significant literature regarding the epidemiology, typical presentation, possible treatment strategies, and prognosis of the most relevant histotypes among rare PCs.

Keywords: Rare pancreatic cancers; Pancreatic acinar cell cancer; Pancreatic adenosquamous cancer; Undifferentiated pancreatic cancer; Pancreatoblastoma; Pseudopapillary pancreatic cancer

Core tip: Due to their rarity and lack of consistent literature, rare subtypes of exocrine pancreatic cancer are often assimilated with the more frequent pancreatic ductal adenocarcinoma, even if they have peculiarities in their presentation and treatment strategy. The aim of this review is to summarize the most relevant literature regarding these rare subtypes of pancreatic cancers.