الفهرس 
Introduction and Aim of the WorkOnly 14 pages are availabe for public view
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Abstract
U
C is an autoimmune chronic IBD of unknown etiology that manifests as continuous inflammation that begins in the rectum and progressively affects the entire colon. The disease is characterized by periods of exacerbation and remission. Endoscopic features of inflammation include loss of vascular pattern, mucosal granularity and friability, erosions, and in severe cases, deep ulceration and spontaneous bleeding.
The ESGE Guideline recommends obtaining segmental biopsies from various segments of the colon in patients with clinical and endoscopic signs of colitis. These biopsies should be placed in separate specimen containers, including the ileum, cecum, ascending, transverse, descending, sigmoid colon, and rectum.
Furthermore, for patients with known UC and endoscopic signs of inflammation, the guideline suggests obtaining at least two biopsies from the most severely affected areas to assess disease activity or the presence of cytomegalovirus.
Histopathology plays a crucial role in determining disease activity and structural changes in UC. The histopathologic features of UC include inactive inflammation, active inflammation, structural changes, and epithelial cell abnormalities. Non-active inflammation is characterized by the presence of lymphocytes and plasma cells in the lamina propria, along with basal plasmacytosis and basal lymphoid aggregates.
Active inflammation is indicated by the presence of neutrophils in the lamina propria, crypts, or surface epithelium, which can lead to mucosal erosions, ulcerations, cryptitis, and crypt abscesses. Structural changes include crypt architectural distortion, decreased crypt density, and surface irregularity.
Epithelial cell abnormalities involve mucin depletion and Paneth cell metaplasia. It is important to note that eosinophils should not be solely relied upon as an indicator of histological activity in UC. The histological features of UC can vary over time and may be influenced by therapeutic interventions.
In the early stages of the disease, diagnosing UC may be challenging and not ruled out by preserved crypt architecture or absence of mucosal transmural inflammation. The earliest histological diagnostic feature to appear is focal basal plasmacytosis.
In longstanding disease, widespread distortion of crypt architecture and increased lamina propria make diagnosis easier. However, rectal sparing, cecal patch, and backwash ileitis may lead to misdiagnosis. During the course of treatment, the pattern of distribution in UC might switch from continuous to discontinuous pattern. In the quiescent phase (clinically inactive), neutrophils may not be seen, but the mucosa still shows structural abnormalities and reduced crypt density, indicating chronic mucosal injury.
Given the presence of numerous conditions that can mimic UC, it is advised that pathologists have access to comprehensive clinical, endoscopic, radiological, and microbiological information to ensure an accurate diagnosis. These mimickers include CD, IC, Infective colitis, Drug-induced colitis, SCAD, chronic ischemic colitis, Diversion colitis, Radiation colitis, and Microscopic colitis.
The Mayo Score is a comprehensive scale used to assess the severity of UC by combining endoscopic and clinical evaluations. It includes PROs (SF and RB), endoscopic appearance of the mucosa, and a PGA. The MES is used to assess the severity of UC based on endoscopic findings. A score of 0 indicates normal mucosa or inactive UC. A score of 1 represents mild disease with mild friability, reduced vascular pattern, and mucosal erythema. A score of 2 indicates moderate disease with friability, erosions, complete loss of vascular pattern, and significant erythema. Finally, a score of 3 indicates the presence of ulceration and spontaneous bleeding. In clinical studies, remission is defined as a MES of 0 or 1 and the absence of rectal bleeding. The pMayo Score includes assessments of SF, RB, and PGA, but does not include the ES. This allows for a more practical evaluation of disease activity in UC without the need for frequent endoscopic procedures.
The IBD-DCA score was developed during the International Consensus Conference on IBD in 2020. It consists of three main parameters: distribution (D), chronicity (C), and activity (A). The score is assessed in the same order.
Parameter D assesses the distribution of active or chronic changes in the colon biopsy, with D0 indicating normal mucosa, D1 indicating changes in less than 50% of tissue fragments, and D2 indicating changes in 50% or more of the tissue received.
Parameter C evaluates chronic injury features, with C0 indicating no chronic changes, C1 indicates mild elevation in lymphoplasmacytic cell count and/or crypt distortion, slightly exceeding normal levels. C2 indicates a marked increase in lymphoplasmacytic cell count in the lamina propria, regardless of the presence of additional crypt distortion. Notably, marked basal lymphoplasmacytosis is also considered C2.
Parameter A assesses activity features, with A0 indicating the absence of neutrophilic granulocytes, A1 indicates an increase of two or more neutrophils in the lamina propria or one or more neutrophils in the epithelium in one HPF, and A2 indicating the presence of crypt abscesses, erosion, or ulceration. The IBD-DCA score was validated and tested for reliability among pathologists from different centers and has shown potential value in routine diagnostics and clinical studies.
This retrospective study analyzed 50 cases of UC focusing on clinical, endoscopic, and histological data. Endoscopic activity was assessed using the MES, while clinical activity was determined by the pMayo score. Histological activity was evaluated using the IBD-DCA scoring system. To enable comparison between the two scores, both of them underwent conversions into a 3-tiered grading system.
The correlation analysis between the MES grade and the IBD-DCA grade as well as parameter A did not yield significant results. Conversely, there was a significant correlation between the MES grade and the IBD-DCA parameters D and C. All patients (100%) in endoscopic remission (MES 0 or 1) still exhibit histologic activity resulting in an insignificant relation between endoscopic remission using MES grade and the IBD-DCA grades. There was a highly significant correlation between the pMayo score and the IBD-DCA grade, as well as significant correlations between the pMayo score and the DCA parameters D, C, and A. Patients who were in clinical remission (pMayo ≤1) were graded by IBD-DCA grade 1 (57.1%) more than grade 2 (42.9%). Additionally, patients who were not in clinical remission (pMayo ≥2) were graded by IBD-DCA grade 2 (88.4%) more than grade 1 (11.6%). These results indicate a significant association between clinical remission based on the pMayo score and the IBD-DCA grades. However, it is important to note that all patients in clinical remission still exhibited histological activity. The relationship between the pMayo score and MES grade was examined, which revealed a highly significant. Furthermore, there was a highly significant correlation between the clinical remission using pMayo score and MES.
Our findings emphasize that combining histologic remission as a treatment target along with clinical and endoscopic remission may lead to better long-term outcomes for UC patients. Therefore, multidisciplinary care, and individualized treatment plans are essential in managing UC effectively.