Colorectal dysplasia in chronic inflammatory bowel disease: a contemporary consensus classification and interobserver study

Inflammatory bowel disease-associated serrated lesions with dysplasia are frequently associated with advanced neoplasia: supporting a unified classification approach

AIMS

Inflammatory bowel disease (IBD)-associated serrated lesions are categorized into three distinct subtypes: traditional serrated adenoma (TSA)-like lesion, sessile serrated lesion (SSL)-like lesion, and serrated lesion, not otherwise specified (NOS). Although the risk of neoplastic progression of serrated lesions without dysplasia has not been shown to exceed that of sporadic cases, the clinicopathologic features of the three serrated subtypes with dysplasia remain poorly understood in the context of IBD.

METHODS AND RESULTS

We analysed 87 serrated lesions with dysplasia (collectively referred to as serrated dysplasia) identified endoscopically in 58 IBD patients, including 51 (59%) TSA-like dysplasia, 24 (28%) SSL-like dysplasia, and 12 (14%) serrated dysplasia NOS. Inclusion criteria required all three serrated subtypes to show morphologic evidence of dysplasia and to be located within areas of colitis. We also compared the clinicopathologic features of serrated dysplasia with those of 239 conventional (adenomatous) dysplastic lesions from 149 IBD patients. The cohort included 39 (67%) men and 19 (33%) women, with a mean age of 54 years and a mean IBD duration of 20 years. Most patients had ulcerative colitis (n = 41; 71%) and pancolitis (n = 48; 83%). The majority of serrated lesions with dysplasia had a polypoid or visible endoscopic appearance (n = 73; 84%), with a mean size of 1.4 cm, and were found in the left colon (n = 66; 76%). Most lesions (n = 73; 84%) demonstrated low-grade dysplasia at the time of biopsy diagnosis, whereas high-grade dysplasia (HGD) was identified in the remaining 14 (16%) lesions. SSL-like dysplasia was more frequently associated with ulcerative colitis (94%) compared to TSA-like dysplasia (67%) and serrated dysplasia NOS (56%) (P = 0.042). Although only seven (12%) patients had a concurrent history of primary sclerosing cholangitis, it was exclusively identified in the TSA-like dysplasia group (19% versus 0% in both the SSL-like dysplasia group and the serrated dysplasia NOS group; P = 0.017). Serrated dysplasia NOS more commonly demonstrated HGD at the time of biopsy diagnosis (42%) compared to TSA-like dysplasia (12%) and SSL-like dysplasia (13%) (P = 0.022). Serrated dysplasia NOS was also more frequently associated with synchronous and/or metachronous nonconventional dysplasia (60%) compared to TSA-like dysplasia (16%) and SSL-like dysplasia (9%) (P = 0.037). Serrated dysplasia, regardless of subtype, was associated with high rates of advanced neoplasia (HGD or colorectal cancer) at the previous biopsy site or in the same colonic segment during follow-up. Within a mean follow-up time of 13 months, advanced neoplasia was detected in 50% of the TSA-like dysplasia group, 67% of the SSL-like dysplasia group, and 100% of the serrated dysplasia NOS group (P = 0.622). Moreover, at least one-third of patients in each group (58% in the TSA-like dysplasia group, 44% in the SSL-like dysplasia group, and 33% in the serrated dysplasia NOS group; P = 0.332) developed synchronous/metachronous dysplasia, with at least 50% of these lesions progressing to advanced neoplasia within a mean follow-up time of 11 months (P = 1.000). The serrated dysplasia group showed nearly six times the incidence of advanced neoplasia upon follow-up (59%) compared to the conventional dysplasia group (10%) (P < 0.001).

CONCLUSION

TSA-like dysplasia, SSL-like dysplasia, and serrated dysplasia NOS show distinct clinicopathologic features. However, all three serrated subtypes were associated with high rates of advanced neoplasia (50%-100%) during follow-up, suggesting that these lesions could potentially be combined into one diagnostic category, such as serrated dysplasia.

"Artificial histology" in colonic Neoplasia: A critical approach

BACKGROUND

The histological assessment of colorectal precancer and cancer lesions is challenging and primarily impacts the clinical strategies of secondary colon cancer prevention. Artificial intelligence (AI) models may potentially assist in the histological diagnosis of this spectrum of phenotypical changes.

OBJECTIVES

To provide a current overview of the evidence on AI-based methods for histologically assessing colonic precancer and cancer lesions.

METHODS

Based on the available studies, this review focuses on the reliability of AI-driven models in ranking the histological phenotypes included in colonic oncogenesis.

RESULTS

This review acknowledges the efforts to shift from subjective pathologists-based to more objective AI-based histological phenotyping. However, it also points out significant limitations and areas that require improvement.

CONCLUSIONS

Current AI-driven methods have not yet achieved the expected level of clinical effectiveness, and there are still significant ethical concerns that need careful consideration. The integration of "artificial histology" into diagnostic practice requires further efforts to combine advancements in engineering techniques with the expertise of pathologists.

Dysplasia in Pediatric Patients with Inflammatory Bowel Disease Shows Distinct Clinicopathologic Features Compared to that in Adult Patients

Due to its rarity, there is limited information on the clinicopathologic features of dysplasia in pediatric patients with inflammatory bowel disease (IBD). The existing surveillance guidelines for these patients do not include dysplasia as a potential risk factor for colorectal cancer (CRC), and there is no clear guidance on the optimal strategy for detecting dysplasia. As such, we analyzed the clinicopathologic features of 20 IBD patients who developed at least one instance of dysplasia (n = 56) before the age of 21 years. The results were then compared with data from a previously published adult cohort, which included 315 dysplastic lesions from 167 consecutive adult IBD patients. The study group consisted of 11 males and 9 females, with a mean age of 11 years at the time of IBD diagnosis. The mean age at the time of the first dysplasia diagnosis was 18 years for the study group compared to 54 years for the adult group. The study group had a lower incidence of ulcerative colitis (65% vs. 92% in the adult group, p < 0.001), but the proportion of patients with concurrent primary sclerosing cholangitis (PSC) was nearly double that of the adult group (25% vs. 13%, p = 0.129). Dysplasia in the study group was more likely to be nonconventional (38%, p = 0.047) and invisible or flat (50%, p < 0.001) compared to the adult group (25% and 24%, respectively). High-risk nonconventional dysplastic subtypes, including crypt dysplasia (13%, p = 0.016), goblet cell-deficient dysplasia (11%, p = 0.010), and hypermucinous dysplasia (9%, p = 0.009), were more common in the study group compared to the adult group (4%, 3%, and 2%, respectively). The mean duration from IBD diagnosis to the first dysplasia diagnosis was significantly shorter in the study group (8 years) than in the adult group (16 years) (p = 0.005). While dysplastic lesions in the adult group were more likely to present as high-grade dysplasia (HGD) at initial diagnosis (17% vs. 4% in the study group, p = 0.008), the rate of advanced neoplasia (HGD or CRC) on follow-up was similar between the two groups (26% in the adult group vs. 22% in the study group, p = 1.000). In conclusion, dysplasia in pediatric IBD patients is often associated with nonconventional features (including the high-risk subtypes), an invisible/flat appearance, concurrent PSC, and early development (within 8 years of IBD diagnosis).

Nonconventional dysplasia in patients with inflammatory bowel disease and colorectal adenocarcinoma: a case-cohort study

BACKGROUND AND AIMS

Patients with inflammatory bowel disease (IBD) face increased risk of colorectal cancer (CRC). While the natural history of conventional dysplastic precursor lesions has been well-studied, the neoplastic potential of recently described nonconventional (NC) IBD-associated colonic mucosal lesions is unclear. We aimed to assess the incidence of antecedent NC lesions in patients with IBD who developed CRC.

METHODS

A case-cohort study was performed to include patients with a diagnosis of IBD with or without CRC who underwent at least 2 surveillance endoscopic procedures at our institution between 1/1/2007 and 5/31/2023. NC lesions included serrated change and indefinite for dysplasia. Detection rates pre- and post-introduction of high-definition (HD) surveillance colonoscopy were compared.

RESULTS

In total, 87 patients with IBD and CRC and 200 patients with IBD without CRC were identified. Of the cases, a majority had ulcerative colitis (n = 52, 60%), most commonly with extensive involvement (n = 46, 89%). Conventional (hazard ratio [HR] 2.18, 95% confidence interval [CI] 1.34-3.52) and NC (HR 2.28, 95% CI 1.59-3.26) lesions were associated with increased risk of CRC. Conventional lesions in the post-HD era appeared to have a stronger association with CRC (HR 2.79, 95% CI 1.62-4.77) than NC lesions (HR 1.62, 95% CI 0.86-3.06).

CONCLUSIONS

Both conventional and NC lesions seem to be associated with increased risk of CRC. Conventional lesions are more strongly associated with CRC than NC lesions in the post-HD era, but misclassifications in the pre-HD era may have resulted in a biased increased risk estimate for NC lesions.

Examination of non-conventional dysplasias adjacent to colorectal adenocarcinoma in patients with IBD

Objective

Recently, several non-conventional variants of IBD-associated dysplasia have been described; however, their prevalence in Central-Eastern Europe is unknown. We aimed to perform a retrospective pilot study by re-evaluating several IBD-associated adenocarcinoma cases to survey the incidence of adjacent non-conventional dysplasia and validate that recent North American findings may apply to a European population.

Methods

Retrospectively, 28 randomly chosen cases of IBD-associated adenocarcinomas diagnosed between 2010 and 2022 were re-evaluated. The patient's sex, age (at the diagnosis of IBD and neoplasia), type of IBD, type of specimen [biopsy (n = 8)/surgical specimen (n = 20)], histological type, grade, localisation, stage, disease-free (DFS) and overall survival (OS) were obtained. Statistical analyses were carried out by using Mann-Whitney (continuous variables), Fisher's exact (categorical variables), Kaplan-Meier (DFS/OS curves), and logrank test (survival curves).

Results

Exclusively, conventional dysplasia was observed in 11, and non-conventional dysplasia in 8 patients. Combined conventional and non-conventional dysplasia was detected in 9 patients. Non-conventional dysplasia showing a combination of multiple subtypes was noted in 10 cases. Altogether, 25 non-conventional dysplastic foci were identified, which were diagnosed as hypermucinous (n = 9), goblet cell-deficient (n = 6), serrated not otherwise specified (NOS) (n = 6), and traditional serrated adenoma-like (n = 4). The majority of non-conventional dysplasias were associated with ulcerative colitis (n = 12). Mucinous adenocarcinoma was exclusively associated with non-conventional dysplasia, while medullary carcinoma was only with conventional dysplasias (p = 0.014 and 0.041).

Conclusion

Based on our results, non-conventional dysplasia is common (60%) adjacent to IBD-associated adenocarcinomas in a Central-Eastern European population and may be detected in biopsies. As multiple recent publications reported evidence of a worse prognosis and more common flat morphology compared to conventional dysplasias, their recognition is of great importance, and stricter follow-up with random biopsy samples may be considered.

Heterogeneity of definition of upper gastrointestinal tract in different guidelines of Crohn's disease: A scoping review

Crohn's Disease (CD) can affect any part of the gastrointestinal (GI) tract, including the upper GI tract (UGIT). However, the definitions and classifications of upper GI CD (UGICD) vary. We conducted a scoping review to explore how UGIT and UGICD are defined and to assess the heterogeneity of these definitions in published CD guidelines, aiming to inform future initiatives for harmonizing definitions. We conducted a search of MEDLINE and Embase for English-language guidelines on CD that mentioned upper GI-related terms in the titles, abstracts, or keywords from inception until 26 July 2024. Definitions of UGIT and UGICD were summarized descriptively. Of 1132 citations, only 19 records met our inclusion criteria. Only eight were identified as CD guidelines. None of them focuses on UGICD. Among these, five diagnostic guidelines explicitly mentioned "upper GI" in their abstracts. Only the joint European Crohn's and Colitis Organisation and European Society of Gastrointestinal and Abdominal Radiology guidelines clearly defined the UGIT. Most guidelines mentioned UGI terms related to upper endoscopy or biopsy only. It was unclear whether these guidelines typically included the esophagus, stomach, and duodenum in the definition of UGICD while excluding the distal small intestine. Although the latest guideline related to pediatric-onset IBD cited the 2011 Paris classification, none of the three guidelines published after that explicitly mentioned the proposed subdivided location of the upper disease. There is a lack of consistent reporting in defining UGICD according to disease location. It is unclear whether there is a consensus on excluding the small intestine beyond the duodenum. Additionally, there is no indication that the subdivided location of UGIT was considered in CD guideline development. Greater consistency in definitions would aid in diagnosis, clinical care, epidemiological research and inclusion into clinical trials. These findings underscore the need for developing a framework to standardize the classification of UGICD, especially for clinical trials.

Gastric-like (pseudopyloric and pseudofoveolar) metaplasia and Paneth cell hyperplasia-neglected histological features of chronic ileal inflammation

Architectural distortion and basal plasmacytosis are the most widely recognized histologic features of chronic ileal inflammation. However, these features might be difficult to assess in small, poorly oriented, or superficial biopsies. Additional features of chronic mucosal damage, including pseudopyloric or pseudofoveolar metaplasia and Paneth cell hyperplasia, have been less commonly reported, and their broader appreciation could facilitate the diagnosis of chronic ileal inflammatory conditions. The prevalence of gastric-like (pseudopyloric and pseudofoveolar) metaplasia and Paneth cell hyperplasia was evaluated in 102 ileal biopsies obtained from patients with Crohn's disease (n = 47), ulcerative colitis with endoscopically normal ileum (n = 20) or with backwash ileitis (n = 20), and nonsteroidal anti-inflammatory drugs- (NSAIDs-) induced ileitis (n = 15). Gastric-like metaplasia was identified in 23% of CD and 13% of NSAID-induced ileitis cases, whereas it was absent among all ulcerative colitis cases. Pseudopyloric metaplasia, pseudofoveolar metaplasia, or a combination of both was documented in 13%, 2%, and 9% of Crohn's disease cases, respectively. NSAID-associated cases showed only pseudopyloric metaplasia. Paneth cell hyperplasia was detected in 43% of Crohn's disease cases, 13% of NSAID-induced ileitis cases, and 5% of backwash ileitis cases. Accordingly, pseudofoveolar metaplasia, pseudopyloric metaplasia, and Paneth cell hyperplasia are not uncommon in conditions causing chronic ileal inflammation. They are most frequently detected in Crohn's disease, but may also be present in NSAID-induced ileitis, whereas they are significantly less common in backwash ileitis and absent in normal ileum. Given the surface localization of pseudofoveolar metaplasia, its identification can be particularly helpful when dealing with poorly oriented or superficial samples.

Dye-based chromoendoscopy detects more neoplasia than white light endoscopy in patients with primary sclerosing cholangitis and IBD

Background and study aims Patients with primary sclerosing cholangitis and inflammatory bowel disease (IBD) have a high risk of colorectal cancer. There is no agreement on the best technique for surveillance for colorectal neoplasia. We aimed to assess whether chromoendoscopy and/or high-definition endoscopy is associated with increased detection of neoplasia in patients with primary sclerosing cholangitis undergoing surveillance compared with when they were not used. Patients and methods This was a single-center, retrospective, observational study designed to analyze differences in the detection of neoplasia (adenomatous and serrated) among patients with primary sclerosing cholangitis and IBD who underwent annual surveillance between 2010 and 2020. Multilevel logistic regression was used to adjust for confounders. Results Ninety-one patients were identified, resulting in 359 colonoscopies with 360 person-years of follow up. Over the study period, 22 of 91 patients (24%) had at least one neoplastic lesion identified; however, the mean neoplastic lesion rate was 0.87 (54/63) for the primary sclerosing cholangitis-ulcerative colitis subgroup compared with 0.24 (4/17) for the primary sclerosing cholangitis-Crohn's disease subgroup. Chromoendoscopy was associated with a significantly higher detection rate for neoplasia (odds ratio [OR] 5.58, 95% confidence interval [CI] 2.08-14.9, P =0.001), and this association remained after adjusting for confounders, including high-definition endoscopy. High-definition endoscopes had a higher rate of neoplasia detection, but the significance was lost after adjustment for confounders, including chromoendoscopy (OR 1.93, 95% CI 0.69-5.40, P =0.21). Conclusions Chromoendoscopy is associated with a higher detection rate for neoplasia in patients with primary sclerosing cholangitis and IBD even with high-definition colonoscopes.

Mutational analysis differentiating sporadic carcinomas from colitis-associated colorectal carcinomas

BACKGROUND

Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) that is associated with increased risk of developing colitis-associated carcinoma (CAC). The genetic profile of CACs is fairly similar to the sporadic colorectal carcinomas (sCRCs), although showing certain differences in the timing and sequence of alterations that contribute to carcinogenesis. Also, both cancer types typically show a strong histological resemblance, which complicates the pathologists' diagnosis. Due to the different clinical consequences, it is of utmost importance to categorize the corresponding cancer type correctly.

METHODS

In this study, we determined the mutation profiles of 64 CACs and sCRCs in the hotspot regions of 50 cancer-associated genes and compared them to 29 controls to identify genetic gene variants that can facilitate the pathologists' diagnosis. Pearson Chi-Square or Fisher's exact tests were used for statistical analyses.

RESULTS

We found that sCRCs tend to mutate more frequently in APC and PIK3CA genes than CACs and that mainly males were affected. Our CAC cohort identified the KRAS G12D mutation as group-specific variant that was not detected in the sCRCs. When separating conventional from non-conventional CACs, it was discovered that the conventional type shows significantly more mutations for ATM.

CONCLUSIONS

Taken together, our data highlights genetic differences between sCRC and CAC and enables the possibility to utilize specific gene alterations to support the pathologist's diagnosis.

Dysplasia Detected in Patients With Serrated Epithelial Change Is Frequently Associated With an Invisible or Flat Endoscopic Appearance, Nonconventional Dysplastic Features, and Advanced Neoplasia

The significance of serrated epithelial change (SEC), defined as endoscopically invisible hyperplastic polyp (HP)-like mucosal change identified in patients with inflammatory bowel disease (IBD), remains unclear. Although some studies reported an increased risk of synchronous and/or metachronous colorectal neoplasia in patients with SEC, including advanced neoplasia (high-grade dysplasia or colorectal cancer), the development of SEC is not significantly associated with increased colonic inflammation. This contrasts with the reported positive correlation between increased colonic inflammation and the risk of colorectal neoplasia in ulcerative colitis, arguing against the notion that SEC may represent a form of dysplasia. As such, this study aimed to characterize the features of synchronous and metachronous dysplasia detected in patients with SEC to identify factors contributing to the increased risk of colorectal neoplasia, including advanced neoplasia, observed in a subset of these patients. Clinicopathologic features of 46 IBD patients with SEC (n=109) and synchronous and/or metachronous dysplasia (n=153) were analyzed. All dysplastic lesions were subtyped as either conventional or nonconventional dysplasia. As controls, 45 IBD patients with endoscopically visible or polypoid HP (n=75) and synchronous and/or metachronous dysplasia (n=87) were analyzed. The SEC group included 28 (61%) men and 18 (39%) women with a mean age of 58 years and a long history of IBD (mean duration: 23 years). The majority of patients (n=34; 74%) had ulcerative colitis, and 12 (26%) had Crohn's disease. Thirty-nine (85%) patients had a history of pancolitis, and 2 (4%) had concomitant primary sclerosing cholangitis. Twenty-seven (59%) patients had multifocal SEC. SEC was predominantly found in the left colon (n=52; 48%) and rectum (n=34; 31%). Dysplasia in the SEC group was often endoscopically invisible or flat (n=42; 27%) and demonstrated nonconventional dysplastic features (n=49; 32%). Six nonconventional subtypes were identified in the SEC group, including 17 (11%) dysplasia with increased Paneth cell differentiation, 12 (8%) hypermucinous dysplasia, 8 (5%) crypt cell dysplasia, 7 (5%) goblet cell deficient dysplasia, 3 (2%) sessile serrated lesion-like dysplasia, and 2 (1%) traditional serrated adenoma-like dysplasia. Advanced neoplasia was detected in 11 (24%) patients. The SEC group was more likely to have nonconventional dysplasia (32%, P <0.001), invisible/flat dysplasia (27%, P <0.001), and advanced neoplasia (24%, P <0.001) than the control group (7%, 2%, and 0%, respectively). High-risk nonconventional subtypes (ie, hypermucinous, crypt cell, and goblet cell deficient dysplasias) accounted for 18% of all dysplastic lesions in the SEC group, which were not seen in the control group ( P <0.001). The SEC group (n=35; 76%) also had a higher rate of concordance between the location of SEC and the area of synchronous/metachronous dysplasia than the control group (n=22; 49%) ( P =0.007). In conclusion, dysplasia detected in patients with SEC is often endoscopically invisible/flat (27%), nonconventional (32%, including the high-risk subtypes), and found in the same colonic segment as SEC (76%), which may in part explain why some patients with SEC are associated with an increased risk of colorectal neoplasia, including advanced neoplasia. The finding of SEC may warrant a careful follow-up colonoscopy with increased random biopsy sampling, especially in the segment of colon with SEC.

Clinicopathologic and Molecular Characterization of Inflammatory Bowel Disease-Associated Neuroendocrine Carcinomas and Mixed Neuroendocrine-Non-Neuroendocrine Neoplasms

The pathogenesis of neuroendocrine carcinomas (NECs) and mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) in the gastrointestinal tract remains poorly understood. This study aims to characterize the clinicopathologic and molecular features of NEC/MiNEN in patients with inflammatory bowel disease (IBD). Eighteen surgically resected IBD-associated intestinal carcinomas with a minimum of 30% neuroendocrine component were collected from 6 academic centers and compared with a control group of 12 IBD-associated carcinomas lacking neuroendocrine differentiation. Both groups exhibited a male predominance and similar age distribution. The NEC/MiNEN group was more likely to have a higher percentage of Crohn disease (9/18 vs 1/12; P = .024), occur in the rectum (9/18 vs 3/12) and small intestine (4/18 vs 0/12) (P < .01), be diagnosed on resection without a preceding biopsy (6/18 vs 0/12; P = .057), and have unidentifiable precursor lesions (10/18 vs 1/12; P = .018) than the control group. Synchronous carcinoma, advanced tumor stage (pT3 and pT4), and lymph node metastasis occurred at similar rates; however, the NEC/MiNEN group had a higher incidence of angiovascular invasion (14/18 vs 4/12; P = .024), distant metastasis (8/18 vs 1/12; P = .049), mortality (8/18 vs 2/12; P = .058), and worse survival (Kaplan-Meier; P = .023) than the control group. All tested cases were mismatch repair proficient. A Ki-67 proliferation index ranged from 25% to 100%. Next-generation sequencing in 11 NEC/MiNEN cases revealed low tumor mutational burdens but complex genetic abnormalities commonly involving TP53 (9/11; 82%), FBXW7 (4/11; 36%), and APC (3/11; 27%) genes, with the other genetic alterations randomly occurring in 1 or 2 cases. The neuroendocrine component, which shared similar molecular alterations as the nonneuroendocrine component, was subcategorized into intermediate (G3a) and high grade (G3b); the higher grade correlated with more genetic alterations. In conclusion, IBD-associated NEC/MiNEN shows diverse histologic features, variable precursor lesions, intricate genetic abnormalities, and aggressive biologic behavior. The classification and grading of gastrointestinal NEC/MiNEN may be refined for better clinical management.

Increased Active Inflammation in the Colon is Not a Reliable Predictor of an Elevated Risk of Dysplasia in Patients With Primary Sclerosing Cholangitis and Ulcerative Colitis

Although the increased risk of colorectal neoplasia in patients with both primary sclerosing cholangitis (PSC) and ulcerative colitis (UC; termed PSC-UC) is well documented, the mechanism through which concomitant PSC increases the risk of colorectal neoplasia remains unclear. Given that the risk of colorectal neoplasia in UC is positively correlated with increased histologic inflammation, this study sought to investigate whether increased histologic inflammation could be used to stratify the risk of dysplasia development in patients with PSC-UC. Twenty patients with PSC-UC and dysplasia were compared with 30 control patients with PSC-UC who had no history of neoplasia. For each patient, all surveillance biopsies were scored using a 4-point scoring system: (1) no epithelial neutrophils = 0, (2) cryptitis only = 1, (3) cryptitis plus crypt abscess in <50% of crypts = 2, and (4) crypt abscess in ≥50% of crypts, erosion, neutrophilic exudate, and/or ulceration = 3. A score was designated for each biopsy, and both mean and maximum inflammation scores were calculated from all biopsies taken during each colonoscopy. The inflammation burden score was calculated for each surveillance interval by multiplying the average maximum score between each pair of surveillance episodes by the length of the surveillance interval in years. The average scores derived from all colonoscopies for each patient were used to determine the patient's overall mean, maximum, and inflammation burden scores. In both the dysplasia and control groups, the 3 summative inflammation scores were calculated independently for the entire colon, right colon, and left colon. The dysplasia group consisted of 14 (70%) men and 6 (30%) women, with a mean age of 27 years at UC diagnosis and a long history of pancolitis (mean duration: 17 y). A total of 49 dysplastic lesions were detected in the dysplasia group, and 8 (40%) of the 20 patients had multifocal dysplasia. The majority of dysplastic lesions belonged to nonconventional subtypes (n = 28; 57%) and were located in the right colon (n = 37; 76%). Irrespective of the colon segment, there was no significant difference in the 3 summative inflammation scores between the dysplasia and control groups ( P > 0.05). However, in each group, the 3 summative inflammation scores were significantly higher in the right colon than in the left colon ( P < 0.05). In conclusion, patients with PSC-UC exhibit increased histologic inflammation in the right colon compared with the left colon, regardless of the presence of dysplasia. Although this may provide an explanation for the predominance of right-sided colorectal neoplasia in patients with PSC-UC, increased histologic inflammation does not reliably predict an elevated risk of dysplasia in patients with PSC-UC. These findings reinforce the current recommendation for annual endoscopic surveillance for all patients with PSC-UC, irrespective of the extent and severity of inflammation.

Molecular profiling of visible polypoid and invisible conventional intestinal-type low-grade dysplasia in patients with idiopathic inflammatory bowel disease

AIMS

Little is known about the molecular features of visible polyps with low-grade intestinal-type dysplasia in patients with inflammatory bowel disease (IBD). To better understand their origins and biological potential, we sought to genomically profile these lesions and compare them with invisible low-grade dysplasia and sporadic adenomas from non-IBD patients.

METHODS

22 polyps within areas of colitis, 13 polyps outside areas of colitis, 10 foci of invisible dysplasia from patients with IBD and 6 sporadic tubular adenomas from non-IBD patients were analysed using the OncoPanel assay.

RESULTS

Polyps arising in areas of colitis showed a greater spectrum of mutations, including APC, KRAS, FBXW7, TP53, ARID1A and TCF7L2. Polyps outside colitis and non-IBD sporadic adenomas showed a limited mutational profile, with APC and CTNNB1 mutations. Invisible dysplasia was characterised by TP53, CTNNB1 and KRAS alterations. Compared with dysplastic polyps, none of the invisible dysplastic foci showed APC alterations (73%-within colitis; p=0.0001, 92%-outside colitis; p<0.0001, 83%-sporadic adenomas; p=0.001). TP53 mutations were significantly higher in invisible dysplasia (50%) compared with polyps within colitis (9%; p=0.02) and outside colitis (8%; p=0.03).

CONCLUSIONS

Molecular alterations in visible low-grade dysplastic polyps with conventional intestinal-type dysplasia from patients with IBD and sporadic adenomas from non-IBD patients overlap significantly. APC alterations appear to play a major role in the development of visible low-grade dysplastic lesions in patients with IBD, regardless of background colitis. As with IBD-associated colorectal cancers, TP53 mutations are an early event in the development of invisible, low-grade conventional intestinal-type dysplasia in patients with IBD.

Nonconventional Dysplasia is Frequently Associated With Goblet Cell Deficient and Serrated Variants of Colonic Adenocarcinoma in Inflammatory Bowel Disease

Various subtypes of nonconventional dysplasia have been recently described in inflammatory bowel disease (IBD). We hypothesized that goblet cell deficient dysplasia and serrated dysplasia may be the primary precursor lesions for goblet cell deficient (GCDAC) and serrated (SAC) variants of colonic adenocarcinoma, respectively. Clinicopathologic features of 23 GCDAC and 10 SAC colectomy cases were analyzed. All dysplastic lesions found adjacent to the colorectal cancers (n = 22 for GCDACs and n = 10 for SACs) were subtyped as conventional, nonconventional, or mixed-type dysplasia. As controls, 12 IBD colectomy cases with well to moderately differentiated adenocarcinoma that lacked any mucinous, signet ring cell, low-grade tubuloglandular, or serrated features while retaining goblet cells throughout the tumor (at least 50% of the tumor) were evaluated. The cohort consisted of 19 (58%) men and 14 (42%) women, with a mean age of 53 years and a long history of IBD (mean duration: 18 y). Twenty-seven (82%) patients had ulcerative colitis. GCDACs (57%) were more often flat or invisible than SACs (10%) and controls (25%; P = 0.023). The GCDAC and SAC groups were more likely to show lymphovascular invasion (GCDAC group: 52%, SAC group: 50%, control group: 0%, P = 0.001) and lymph node metastasis (GCDAC group: 39%, SAC group: 50%, control group: 0%, P = 0.009) than the control group. Notably, GCDACs and SACs were more frequently associated with nonconventional dysplasia than controls (GCDAC group: 77%, SAC group: 40%, control group: 0%, P < 0.001). Goblet cell deficient dysplasia (73%) was the most prevalent dysplastic subtype associated with GCDACs ( P = 0.049), whereas dysplasias featuring a serrated component (60%) were most often associated with SACs ( P = 0.001). The GCDAC group (75%) had a higher rate of macroscopically flat or invisible synchronous dysplasia compared with the SAC (20%) and control (33%) groups ( P = 0.045). Synchronous dysplasia demonstrated nonconventional dysplastic features more frequently in the GCDAC (69%) and SAC (40%) groups compared with the control group (0%; P = 0.016). In conclusion, goblet cell deficient dysplasia and dysplasias featuring a serrated component could potentially serve as high-risk markers for GCDACs and SACs, respectively.

Pathology and Clinical Significance of Inflammatory Bowel Disease-Associated Colorectal Dysplastic Lesions

Timely diagnosis and effective management of colorectal dysplasia play a vital role in preventing mortality from colorectal cancer in patients with chronic inflammatory bowel disease. This review provides a contemporary overview of the pathologic and endoscopic classification of dysplasia in inflammatory bowel disease, their roles in determining surveillance and management algorithms, and emerging diagnostic and therapeutic approaches that might further enhance patient management.

Recently described types of dysplasia associated with IBD: tips and clues for the practising pathologist

Longstanding inflammatory bowel disease (especially in patients with severely active disease or primary sclerosing cholangitis) is associated with an increased risk of developing dysplasia and adenocarcinoma. This review covers critical clinical aspects, such as risk factors and screening endoscopy basics, emphasising the SCENIC (Surveillance for Colorectal Endoscopic Neoplasia Detection in Inflammatory Bowel Disease International Consensus) guidelines. The histopathological and molecular features of both conventional (adenomatous) dysplasia and the non-conventional subtypes (hypermucinous dysplasia, goblet cell-deficient dysplasia, crypt cell dysplasia, serrated dysplasias) are discussed with an emphasis on challenging diagnostic areas and helpful tips to allow correct categorisation by the practising pathologist.