DALM, rest in peace: a pathologist's perspective on dysplasia in inflammatory bowel disease in the post-DALM era

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.

Focal Cancer in Colitis

Colorectal cancer (CRC) is a known complication of inflammatory bowel disease (IBD). Widely accepted guidelines recommend that patients with ulcerative colitis diagnosed with CRC undergo total proctocolectomy with or without ileal pouch-anal anastomosis, and that patients with Crohn's disease and CRC undergo either total colectomy or proctocolectomy. These approaches are ideal for preventing synchronous and metachronous cancer, minimizing risk of refractory colitis requiring reoperation, and is the appropriate treatment for the vast majority of patients with IBD who are diagnosed with CRC and require surgical intervention. Segmental colectomy, however, may be considered in select patients with IBD and CRC, specifically in elderly patients with short disease duration, in patients with mild colitis identified preoperatively, in patients with high operative risk and prohibitive comorbidities, and in patients whose CRC appears to be sporadic as opposed to colitis-associated. Patients undergoing segmental resection must be closely surveilled postoperatively for dysplasia, recurrent cancer, and refractory colitis.

MYC overexpression in inflammatory bowel disease-associated conventional dysplasia and association of subsequent low-grade dysplasia in follow-up biopsies

OBJECTIVE

Diagnosis of inflammatory bowel disease (IBD)-associated dysplastic lesions can be challenging. This study aims to evaluate MYC immunohistochemistry (IHC) as a potential biomarker for IBD-associated dysplasia and compare its effectiveness with p53 IHC.

METHODS

The study cohort included resections from 12 IBD patients with carcinoma and concurrent conventional low-grade dysplasia (LGD), as well as biopsies from 21 patients with visible conventional LGD, which were followed up for 2 years with subsequent endoscopic examination. MYC and p53 IHC and MYC-FISH analysis were performed.

RESULTS

Sensitivity for LGD detection was 67% (8/12) and 50% (6/12) for MYC and p53, respectively, but the difference was not statistically significant (p = 0.2207). MYC and p53 overexpression were not always mutually exclusive, nor were they always present simultaneously. Patients who presented dysplasia in subsequent biopsies (7/21) were found to be more likely present with multiple LGD polyps and MYC-overexpressed LGD in the initial biopsies, compared to those without subsequent dysplasia (p < 0.05). These dysplastic lesions were commonly associated with chronic colitis (p = 0.0614). The distribution of LGD sites did not show a significant difference between patients with and without subsequent LGD. In MYC overexpressed cases, homogeneously strong nuclear expression was not identified in all dysplastic epithelial cells, and no MYC amplification was found in these cases by FISH.

CONCLUSION

MYC IHC can complement p53 IHC as an adjunct biomarker for diagnosing IBD-associated conventional LGD and can be used for the prediction of subsequent LGD in the follow-up biopsies combined with endoscopic features.

Molecular characterization of visible low-grade dysplastic lesions in patients with inflammatory bowel disease

We studied pathogenic gene mutations and tumor mutation burden (TMB) in visible low-grade dysplastic lesions in patients with inflammatory bowel disease (IBD). The dysplastic lesions with histologically normal mucosa in the background (group 1) were compared with dysplastic lesions occurring either in a background of chronic active colitis (group 2) or associated with synchronous carcinomas regardless of the status of the background mucosa (group 3). The TMB in group 3 was consistently higher in comparison to the group 1 and group 2 lesions, although the difference was not statistically significant. There also seem to be different mutation profiles between the groups, indicating different pathways of tumor pathogenesis. More frequent APC mutations were seen in group 1 as compared to other groups and TP53 mutations were seen in groups 2 and 3, but none in group 1. Molecular characterization could potentially be used as an ancillary prognostic marker in challenging cases to guide the further management of IBD patients with visible dysplastic lesions.

Endoscopic Management of Colitis-Associated Neoplasia

This article reviews the latest data concerning the use of advanced therapeutic techniques for endoscopically treating colitis-associated neoplastic lesions and discusses factors associated with improved outcomes.

Inflammatory bowel disease-related colorectal cancer: Past, present and future perspectives

Inflammatory bowel disease-related colorectal cancer (IBD-CRC) is one of the most serious complications of IBD contributing to significant mortality in this cohort of patients. IBD is often associated with diet and lifestyle-related gut microbial dysbiosis, the interaction of genetic and environmental factors, leading to chronic gut inflammation. According to the “common ground hypothesis”, microbial dysbiosis and intestinal barrier impairment are at the core of the chronic inflammatory process associated with IBD-CRC. Among the many underlying factors known to increase the risk of IBD-CRC, perhaps the most important factor is chronic persistent inflammation. The persistent inflammation in the colon results in increased proliferation of cells necessary for repair but this also increases the risk of dysplastic changes due to chromosomal and microsatellite instability. Multiple pathways have been identified, regulated by many positive and negative factors involved in the development of cancer, which in this case follows the ‘inflammation-dysplasia-carcinoma’ sequence. Strategies to lower this risk are extremely important to reduce morbidity and mortality due to IBD-CRC, among which colonoscopic surveillance is the most widely accepted and implemented modality, forming part of many national and international guidelines. However, the effectiveness of surveillance in IBD has been a topic of much debate in recent years for multiple reasons — cost-benefit to health systems, resource requirements, and also because of studies showing conflicting long-term data. Our review provides a comprehensive overview of past, present, and future perspectives of IBD-CRC. We explore and analyse evidence from studies over decades and current best practices followed globally. In the future directions section, we cover emerging novel endoscopic techniques and artificial intelligence that could play an important role in managing the risk of IBD-CRC.

The Role of the Immune System in IBD-Associated Colorectal Cancer: From Pro to Anti-Tumorigenic Mechanisms

Patients with inflammatory bowel disease (IBD) have increased incidence of colorectal cancer (CRC). IBD-associated cancer follows a well-characterized sequence of intestinal epithelial changes, in which genetic mutations and molecular aberrations play a key role. IBD-associated cancer develops against a background of chronic inflammation and pro-inflammatory immune cells, and their products contribute to cancer development and progression. In recent years, the effect of the immunosuppressive microenvironment in cancer development and progression has gained more attention, mainly because of the unprecedented anti-tumor effects of immune checkpoint inhibitors in selected groups of patients. Even though IBD-associated cancer develops in the background of chronic inflammation which is associated with activation of endogenous anti-inflammatory or suppressive mechanisms, the potential role of an immunosuppressive microenvironment in these cancers is largely unknown. In this review, we outline the role of the immune system in promoting cancer development in chronic inflammatory diseases such as IBD, with a specific focus on the anti-inflammatory mechanisms and suppressive immune cells that may play a role in IBD-associated tumorigenesis.

The Fate of Unifocal Versus Multifocal Low-Grade Dysplasia at the Time of Colonoscopy in Patients With IBD

BACKGROUND

Recommendations regarding management of colorectal dysplasia in the setting of IBD continue to evolve.

OBJECTIVE

This study aimed to determine the rate of progression from dysplasia to adenocarcinoma, specifically focusing on the differences in unifocal and multifocal low-grade dysplasia and dysplasia found on random biopsy versus targeted biopsies.

DESIGN

This is a retrospective review.

SETTING

This study was conducted at an IBD referral center.

PATIENTS

All adult patients (≥18 years of age) with a known diagnosis of either ulcerative colitis or Crohn's disease, who underwent a surveillance colonoscopy between January 1, 2010 and January 1, 2019, were selected.

MAIN OUTCOMES MEASURES

The primary outcomes measured were the progression of dysplasia and the risk factors for progression.

RESULTS

A total of 23,751 surveillance colonoscopies were performed among 12,289 patients between January 1, 2010 and January 1, 2019. The mean age at colonoscopy was 52.1 years (SD 16.9 years), 307 patients (2.5%) had a history of primary sclerosing cholangitis, and 3887 (3.15%) had a family history of colorectal cancer. There was a total of 668 patients (5.4%) with low-grade dysplasia, 76 patients (0.62%) with high-grade dysplasia, and 68 patients (0.55%) with adenocarcinoma in the series. The 1-, 2-, and 5-year cumulative incidence rate of progressing from low-grade dysplasia to high-grade dysplasia were 1.6%, 4.8%, and 7.8%. The 1- and 2-year cumulative incidence rates of progressing from low-grade dysplasia to adenocarcinoma were 0.7% and 1.6%. There were no significant differences in unifocal and multifocal progression. Primary sclerosing cholangitis, ulcerative colitis, male sex, and advanced age were all found to be significant risk factors for neoplasia on multivariable analysis.

LIMITATIONS

A retrospective database was a source of information.

CONCLUSION

Progression of low-grade dysplasia to adenocarcinoma, regardless of its being unifocal or multifocal, remains very low in the setting of adequate surveillance and medical management. The presence of multifocal low-grade dysplasia should not change the decision making to pursue ongoing endoscopic surveillance versus proctocolectomy. Patients who had primary sclerosing cholangitis with dysplasia found on random biopsies may be at highest risk for dysplasia progression. See Video Abstract at http://links.lww.com/DCR/A649.

EL DESENLACE DE LA DISPLASIA DE BAJO GRADO UNIFOCAL VERSUS MULTIFOCAL DURANTE LA COLONOSCOPIA EN PACIENTES CON ENFERMEDAD INFLAMATORIA INTESTINAL

ANTECEDENTES:Las recomendaciones para el tratamiento de la displasia colorrectal en el contexto de la enfermedad inflamatoria intestinal siguen evolucionando.OBJETIVO:Determinar la tasa de progresión de displasia a adenocarcinoma, centrándose específicamente en las diferencias en displasia de bajo grado unifocal y multifocal, y displasia encontradas en biopsias aleatorias versus biopsias dirigidas.DISEÑO:Revisión retrospectiva.ÁMBITO:Centro de referencia de EII.PACIENTES:Todos los pacientes adultos (> 18 años) con un diagnóstico comprobado de colitis ulcerosa o enfermedad de Crohn que se sometieron a una colonoscopia de vigilancia entre el 1 de enero de 2010 y el 1 de enero de 2019.PRINCIPALES VARIABLES ANALIZADAS:Progresión de la displasia y factores de riesgo de progresión.RESULTADOS:Se realizaron un total de 23.751 colonoscopias de vigilancia en 12.289 pacientes entre el 1/1/2010 y el 1/1/2019. La edad media en el momento de la colonoscopia fue de 52,1 años (DE 16,9 años), 307 pacientes (2,5%) tenían antecedentes de colangitis esclerosante primaria y 3887 (3,15%) tenían antecedentes familiares de cáncer colorrectal. Hubo un total de 668 pacientes (5,4%) con displasia de bajo grado, 76 pacientes (0,62%) con displasia de alto grado y 68 pacientes (0,55%) con adenocarcinoma en la serie. La tasa de incidencia acumulada de 1, 2, 5 años de progresión de displasia de bajo grado a displasia de alto grado fue del 1,6%, 4,8% y 7,8%. Las tasas de incidencia acumulada de 1 y 2 años de progresión de displasia de bajo grado a adenocarcinoma fueron 0,7% y 1,6%, respectivamente. No hubo diferencias significativas en la progresión unifocal y multifocal. Se encontró que la colangitis esclerosante primaria, la colitis ulcerosa, el sexo masculino y la edad avanzada eran factores de riesgo significativos de neoplasia en el análisis multivariable.LIMITACIONES:Base de datos retrospectiva.CONCLUSIÓN:La progresión de la displasia de bajo grado a adenocarcinoma, independientemente de que sea unifocal o multifocal, sigue siendo muy baja en el contexto de una vigilancia y un tratamiento médico adecuados. La presencia de displasia multifocal de bajo grado no debería cambiar la toma de decisión para continuar con vigilancia endoscópica continua o realizar la proctocolectomía. Los pacientes con colangitis esclerosante primaria y displasia encontrada en biopsias aleatorias pueden tener una mayor progresión de la displasia. Consulte Video Resumen en http://links.lww.com/DCR/A649.

Management of Dysplasia in Ulcerative Colitis

Surveillance colonoscopies for patients with ulcerative colitis (UC) are necessary to monitor for the development of cancer and its precursor, dysplasia. The management of dysplasia in the setting of UC has been evolving over the past two decades. This is in large part due to higher resolution colonoscopes and development of advanced endoscopic techniques, such as chromoendoscopy, endoscopic mucosal resection, and endoscopic submucosal dissection. Mucosal evaluation, as well as identification and removal of dysplastic tissue, has improved markedly, such that the majority of dysplasia is now considered visible. Whereas previously random biopsies were deemed necessary for surveillance, currently their value is uncertain. Surveillance with high-definition colonoscopes is recommended and consideration of chromoendoscopy is suggested. During colonoscopy, if visible dysplasia is identified and removed completely, continued surveillance is appropriate. If dysplasia is unresectable or there are other high-risk factors such as primary sclerosing cholangitis or multifocality, patients should undergo colectomy. If random biopsies are taken and high-grade dysplasia is identified, that is, invisible dysplasia, patients should similarly consider colectomy. Surgical options include total proctocolectomy with end ileostomy versus ileal pouch-anal anastomosis. Patients undergoing pouch surgery must continue surveillance for dysplasia of the rectal cuff and the pouch. Although surgical management remains an important option for dysplasia in the setting of UC, endoscopic surveillance and resection have improved tremendously, leading to a shift in the overall management strategies for these patients.

Histopathology of IBD Colitis. A practical approach from the pathologists of the Italian Group for the study of the gastrointestinal tract (GIPAD)

Inflammatory bowel diseases (IBDs) are lifelong disorders in which an interaction between genetic and environmental factors is involved. IBDs include two entities: Crohn's disease (CD) and ulcerative colitis (UC); these can be adequately diagnosed and distinguished with a correct methodological approach based on communicating exhaustive clinical, endoscopic and laboratory information to the pathologist and performing adequate bioptic sampling and precise morphological signs including crypt architecture, distribution of inflammation and granulomas, when present. IBD needs to be distinguished from non-IBD colitis, mostly at its onset. Moreover, IBDs are associated with an increased risk of developing colorectal adenocarcinoma. In daily pathological practice, correct diagnosis of IBD and its subclassification as well as a correct detection of dysplasia is imperative to establish the best therapeutic approach.

The 2019 World Health Organization Classification of appendiceal, colorectal and anal canal tumours: an update and critical assessment

The recently published 5th edition 2019 World Health Organization (WHO) Classification of Tumours of the Digestive System brings significant changes from the 2010 4th edition. An emphasis on uniformity in nomenclature and grading for tumours across all organ systems is a particular feature of the 5th edition blue book series that is reflected in the gastrointestinal tract (GIT) classification. For example, simplified two tiered grading is reinforced for preinvasive lesions throughout the GIT, with dysplasia at all sites now being considered either low or high grade. Similarly, a uniform approach to classification and grading of GIT neuroendocrine neoplasms has been consolidated, with an emphasis on distinguishing grade 3 neuroendocrine tumours from neuroendocrine carcinomas. In this review, we discuss and critically assess the important and sometimes controversial changes made to the classification of tumours of the lower GIT, comprising the colorectum, vermiform appendix and anal canal. The particularly controversial decision to endorse the term 'sessile serrated lesion' for lesions previously termed 'sessile serrated polyp/adenoma' is explored. The morphological, molecular, and clinical insights behind the substitution of the term 'goblet cell adenocarcinoma' for 'goblet cell carcinoid' are assessed. The evolution of the classification of appendiceal mucinous neoplasms is considered. Inflammatory bowel disease related dysplasia and its evolving subtypes, with major implications for pathologists in routine practice, is explained.

Dysplastic Progression to Adenocarcinoma is Equivalent in Ulcerative Colitis and Crohn's Disease

BACKGROUND

We sought to determine the rate of progression from dysplasia to adenocarcinoma in ulcerative colitis [UC] vs Crohn's diseases [CD] and describe the risk factors unique to each.

METHODS

All adult patients [≥18 years] with a known diagnosis of either UC or CD who underwent a surveillance colonoscopy between January 1, 2010 and January 1, 2020 were included.

RESULTS

A total of 23 751 surveillance colonoscopies were performed among 12 289 patients between January 1, 2010 and January 1, 2020; 6909 [56.2%] had a diagnosis of CD and 5380 [43.8%] had a diagnosis of UC. There were a total of 668 patients [5.4%] with low-grade dysplasia [LGD], 76 patients [0.62%] with high-grade dysplasia [HGD], and 68 patients [0.55%] with adenocarcinoma in the series; the majority of the dysplastic events were located in the right colon. Significantly more UC patients had a dysplastic event, but the rate of LGD and HGD dysplasia progression to adenocarcinoma was not significantly different in CD or UC [p = 0.682 and p = 1.0, respectively]. There was no significant difference in the rate of progression from LGD/HGD to adenocarcinoma based on random biopsies vs targeted biopsies of visible lesions [p = 0.37]. However, the rate of progression from LGD vs HGD to adenocarcinoma was significantly greater for HGD [p < 0.001].

CONCLUSION

While more UC patients were found to have neoplasia on colonoscopy, the rate of progression from LGD and HGD to adenocarcinoma was equivalent in UC and CD, suggesting that endoscopic surveillance strategies can remain consistent for all IBD patients.

Revisiting the distinct histomorphologic features of inflammatory bowel disease-associated neoplastic precursor lesions in the SCENIC and post-DALM Era

Distinct histomorphologic features of colitis-associated dysplasia (CAD) or neoplastic precursors in inflammatory bowel disease (IBD) have never been clearly identified. In this study, we tried to further explore the differentiating morphologic features of CAD by retrospectively reviewing the lesions that were clearly associated with carcinomas (carcinoma-related lesions) and by comparing between endoscopically nonpolypoid (non-adenoma-like) lesions and polypoid (adenoma-like) lesions and sporadic conventional adenomas found in the noncolitic mucosa and in patients without IBD. Our study results have revealed that (1) precursor lesions related to IBD-associated colorectal carcinomas were almost always nonpolypoid in macroscopic/endoscopic appearance; (2) nearly half of the carcinoma-related lesions and nonpolypoid lesions were similarly nonadenomatous (nonconventional) lesions, largely serrated type, with no or only mild/focal adenomatous dysplasia, and commonly had mixed adenomatous and nonadenomatous features; (3) carcinoma-related and nonpolypoid adenomatous dysplastic lesions frequently showed some peculiar histocytologic features that we observed and described for the first time, including mixed features of inflammatory pseudopolyps or granulation tissue, pleomorphic and disarrayed nuclei, micropapillary or hobnailing surface epithelial cells, and microvesicular or bubbling cytoplasm of dysplastic cells; and (4) polypoid lesions in the colitic mucosa were identical to sporadic adenomas in the noninflamed mucosa and in patients without IBD, and they lacked the aforementioned features. The seemingly distinctive morphologic characteristics that we proposed here, although still not absolutely specific or unique, can be used as the features of inclusion for identifying CAD on endoscopic biopsies when the endoscopy images are not readily available to pathologists and thus to alert clinicians for a closer follow-up.

Histological and molecular diversity and heterogeneity of precancerous lesions associated with inflammatory bowel diseases

AIMS

Inflammatory bowel disease (IBD)-associated precancerous lesions may be adenomatous or non-adenomatous with various histomorphologies. We aim to validate the newly proposed classification, to explore the neoplastic nature of the non-adenomatous lesions and to elucidate the molecular mechanisms underlying the different histomorphologies.

METHODS

44 background precursor lesions identified in 53 cases of surgically resected IBD-associated colorectal and ileal carcinomas were reviewed for the histomorphological features (classified into adenomatous, mucinous, sessile serrated adenoma (SSA)-like, traditional serrated adenoma-like, differentiated, eosinophilic and serrated not otherwise specified (NOS)) and analysed for a key panel of colonic cancer-related molecular markers.

RESULTS

Approximately 60% of the lesions were adenomatous, of which some had mixed serrated, mucinous or eosinophilic changes. The remaining non-adenomatous lesions, including all other types except SSA-like type, mostly showed mixed features and focal adenomatous dysplasia. KRAS mutation and p53 mutant-type expression were found in about half cases across all types, while PIK3CA mutation only in some of adenomatous and eosinophilic lesions and MLH1/PMS2 loss in a subset of adenomatous, mucinous and eosinophilic but not in differentiated and serrated lesions. SAT-B2 or PTEN loss and IMP3 overexpression were seen in a small subset of lesions. No BRAF, NRAS or EGFR gene mutation was detected in any type. Certain molecular-morphological correlations were demonstrated; however, no single or combined molecular alteration(s) was specific to any particular morphological type.

CONCLUSIONS

IBD-associated precancerous lesions are heterogeneous both histologically and molecularly. True colitis-associated adenomatous lesions are unlikely conventional adenomas. Non-adenomatous lesions without frank cytologic dysplasia should also be regarded as neoplastic.

Inflammatory bowel disease- and Barrett's esophagus-associated neoplasia: the old, the new, and the persistent struggles

Early diagnosis of and adequate therapy for premalignant lesions in patients with inflammatory bowel disease (IBD) and Barrett's esophagus (BE) has been shown to decrease mortality. Endoscopic examination with histologic evaluation of random and targeted biopsies remains the gold standard for early detection and adequate treatment of neoplasia in both these diseases. Although eventual patient management (including surveillance and treatment) depends upon a precise histologic assessment of the initial biopsy, accurately diagnosing and grading IBD- and BE-associated dysplasia is still considered challenging by many general as well as subspecialized pathologists. Additionally, there are continuing updates in the literature regarding the diagnosis, surveillance, and treatment of these disease entities. This comprehensive review discusses the cancer risk, detailed histopathological features, diagnostic challenges, and updates as well as the latest surveillance and treatment recommendations in IBD- and BE-associated dysplasia.

Clinicopathological and Molecular Specificities of Inflammatory Bowel Disease-Related Colorectal Neoplastic Lesions: The Role of Inflammation

Compared with the general population, patients with inflammatory bowel disease [IBD] have an increased risk of developing colorectal cancer. Molecular mechanisms underlying colorectal carcinogenesis in the setting of IBD are not well understood. However, modern molecular investigative tools have facilitated the identification of features that help distinguish IBD-related carcinoma from sporadic carcinoma. Moreover, with advances in endoscopic technology and improved understanding of the natural history, the management of colorectal neoplastic lesions in IBD patients has evolved. This review discusses the clinicopathological and molecular features of colorectal neoplastic lesions complicating IBD. Chronic inflammation is believed to promote the development of neoplasia, partly by producing reactive oxygen and nitrogen species [ROS and NOS], which may interact with genes involved in carcinogenetic pathways. Furthermore, alterations in microbiota and in the innate and adaptive immune responses might contribute to this process, particularly by initiating, regulating, and sustaining chronic inflammation. Earlier detection and better characterization of neoplastic colorectal lesions complicating IBD and a better knowledge of the molecular mechanisms underlying carcinogenesis in this setting should facilitate improvements in the risk stratification of patients with longstanding IBD and in the management of dysplastic and malignant colorectal lesions that arise in this setting.