Review ArticlesThe Differential Diagnosis of Intrahepatic Ductular Reaction in Medical Liver BiopsyJain, Richa MD; Clark, Ian MDAuthor Information Department of Pathology, Memphis Pathology Group, University of Tennessee Health Sciences Center, Methodist University Hospital, Memphis, TN The authors have no funding or conflicts of interest to disclose. Reprints: Richa Jain, MD, Methodist University Hospital, 6th floor Sherard wing, 1265 Union Avenue, Memphis, TN 38104 (e-mail: [email protected]). All figures can be viewed online in color at www.anatomicpathology.com. Advances In Anatomic Pathology: March 2021 - Volume 28 - Issue 2 - p 72-80 doi: 10.1097/PAP.0000000000000294 Buy Metrics Abstract Intrahepatic ductular reaction is a pathologic proliferation of phenotypical biliary channels. Ductular reactions aim to restore compromised physiological function after liver injury and are one of the archetypal responses of the liver to a wide variety of etiologies, among them are parenchymal loss, biliary tract disease, neoplasms, after liver transplantation, and several pediatric liver diseases. The types and extent of ductular reactions can vary, according to the etiological insult. In this review, the authors will first consider the different mechanisms for ductular reactions and their relevance for liver regeneration. After, the authors will discuss our approach to differential diagnosis for ductular reactions in different patient groups, taking into account clinical history and potential pitfalls. The authors provide an algorithmic approach for practicing pathologists and trainees when confronted by a ductular reaction in a liver biopsy. Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.