[Inflammatory bowel diseases: Scoring and pathological reports optimization]. / Maladies inflammatoires chroniques intestinales : scores et optimisation des comptes rendus anatomopathologiques.

The two main forms of inflammatory bowel disease (IBD) are ulcerative colitis (UC) and Crohn's disease (CD). Both diseases have inflammatory flare-ups that alternate with periods of remission. The pathologist may examine biopsies of the digestive tract from IBD patients in different contexts: at the time of the initial diagnosis, in the event of a disease flare-up in order to differentiate a flare of the disease from another cause, particularly an infectious one, and during the long term follow-up of the disease in order to detect the occurrence of dysplastic lesions. Pathologists are increasingly involved in the evaluation of inflammatory activity during the follow-up of IBD patients. The therapeutic management of IBD has evolved significantly and the emergence of new treatments allows a global approach targeting endoscopic mucosal healing. However, mucosal healing is not always correlated with histological healing. Numerous studies have shown the value of histological evaluation during follow-up. A higher score for histological activity in ulcerative colitis predicts a higher likelihood of neoplasia. Histological activity is a better predictor than endoscopic inflammation of the risk. In UC, histological remission may be a long-term therapeutic goal but its role in CD remains unclear. Different scores have been developed to quantify the inflammatory activity of IBD patients and the response to treatment. The aim of this review is to present the main activity scores used in the follow-up of IBD, their interest, their evaluation and their limitations.

Histological scores in inflammatory bowel disease.

The role of histology in inflammatory bowel disease (IBD) has not yet been well defined. Endoscopic mucosal healing has been proposed as a predictor of the clinical course of IBD and it is indeed considered one of the main therapeutic targets. However, it does not necessarily imply histological healing. Histological remission has been reported to be associated with a better clinical outcome than endoscopic remission only in IBD patients. These observations support the view that histology plays a role as a potential therapeutic target in Crohn's disease and ulcerative colitis. Histological scores being able to quantify the degree of microscopic activity are needed for this purpose. In the era of biologics, indication for proper treatment may benefit from the assessment of clinical and endoscopic activity, as well as histological scores. Such scores may allow us to quantify the microscopic mucosal response to treatment and to define complete healing in IBD. A validated histological score in IBD may lead to the definition of microscopic activity in clinical practice, trials and investigational settings. Several attempts to develop such scores have been reported, but few are currently used and none is applied worldwide in clinical practice. The present review summarizes the main histological scores currently used for assessing IBD activity.