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World J Gastroenterol. Sep 28, 2022; 28(36): 5300-5312
Published online Sep 28, 2022. doi: 10.3748/wjg.v28.i36.5300
Histopathological assessment of the microscopic activity in inflammatory bowel diseases: What are we looking for?
Ondrej Fabian, Lukas Bajer
Ondrej Fabian, Clinical and Transplant Pathology Centre, Institute for Clinical and Experimental Medicine, Prague 14021, Czech Republic
Ondrej Fabian, Department of Pathology and Molecular Medicine, 3rd Faculty of Medicine, Charles University and Thomayer Hospital, Prague 14059, Czech Republic
Lukas Bajer, Hepatogastroenterology Department, Institute for Clinical and Experimental Medicine, Prague 14021, Czech Republic
Lukas Bajer, Institute of Microbiology, Czech Academy of Sciences, Prague 14220, Czech Republic
Author contributions: Fabian O collected the data, performed the data analysis and wrote the paper; Bajer L participated in the data analysis and wrote the paper.
Supported by Ministry of Health of the Czech Republic, No. NV18-09-00493 and No. NU21J-06-00027.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
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: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Ondrej Fabian, MD, PhD, Assistant Professor, Postdoc, Clinical and Transplant Pathology Centre, Institute for Clinical and Experimental Medicine, Videnska 1958/9, Prague 14021, Czech Republic. ondrej.fabian@ikem.cz
Received: July 1, 2022
Peer-review started: July 1, 2022
First decision: August 1, 2022
Revised: August 11, 2022
Accepted: September 8, 2022
Article in press: September 8, 2022
Published online: September 28, 2022
Abstract

Advances in diagnostics of inflammatory bowel diseases (IBD) and improved treatment strategies allowed the establishment of new therapeutic endpoints. Currently, it is desirable not only to cease clinical symptoms, but mainly to achieve endoscopic remission, a macroscopic normalization of the bowel mucosa. However, up to one-third of IBD patients in remission exhibit persisting microscopic activity of the disease. The evidence suggests a better predictive value of histology for the development of clinical complications such as clinical relapse, surgical intervention, need for therapy escalation, or development of colorectal cancer. The proper assessment of microscopic inflammatory activity thus became an important part of the overall histopathological evaluation of colonic biopsies and many histopathological scoring indices have been established. Nonetheless, a majority of them have not been validated and no scoring index became a part of the routine bioptic practice. This review summarizes a predictive value of microscopic disease activity assessment for the subsequent clinical course of IBD, describes the most commonly used scoring indices for Crohn's disease and ulcerative colitis, and comments on current limitations and unresolved issues.

Keywords: Crohn’s disease, Microscopy, Predictor, Score, Ulcerative colitis

Core Tip: Approximately one third of the patients with inflammatory bowel diseases in endoscopic remission show persisting signs of microscopic disease activity. Histology seems to have a predictive value for development of severe clinical complications. Proper assessment of the microscopic activity of the disease using respective scoring indices is thus necessary. This review summarizes the most widely used histological scoring indices, discusses their advantages and limitations and comments persisting unresolved issues from the perspective of gastrointestinal pathologists.