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.

Coexisting Th1 and Th2 cytokines in patients with collagenous gastritis and implications for its pathogenesis

OBJECTIVES

Collagenous gastritis (CG) is a rare cause of refractory dyspepsia and anemia that frequently affects children and young adults and whose histological hallmark is chronic mucosal inflammation with a subepithelial collagen band. The etiology remains obscure, and no established treatments exist. We investigated the pathogenesis of CG by determining the expression profiles of genes related to immunity and inflammation in index biopsies.

METHODS

Gastric biopsies from 10 newly diagnosed patients with CG were evaluated using the NanoString nCounter assay. Gastric biopsies from 14 normal individuals served as controls. The gene expression ratios for CG versus controls were determined in pooled samples and confirmed in individual samples by quantitative reverse transcription polymerase chain reaction. The results were compared with previously reported expression data from a cohort of patients with collagenous colitis, a colonic disorder with similar morphology, including subepithelial collagen band.

RESULTS

CG biopsies featured enhanced expression of key genes encoding both Th1 (IFNγ, TNF-α, IL-2, IL-10, IL-12A, IL-12B, and IL-18) and Th2 cytokines (IL-3, IL-4, IL-5, IL-6, and IL-13). In contrast, biopsies from patients with CC exhibited upregulated Th1 cytokines only.

CONCLUSIONS

We show in this first published gene expression profiling study that CG involves simultaneous upregulation of Th1 and Th2 cytokines. This finding is unique, contrasting with other types of chronic gastritis as well as with collagenous colitis, which shares the presence of a collagen band. Involvement of Th2 immunity in CG would support further investigation of potential dietary, environmental, or allergic factors to guide future therapeutic trials.

Effects of Mirikizumab on Histologic Resolution of Crohn's Disease in a Randomized Controlled Phase 2 Trial

BACKGROUND & AIMS

Histologic evaluation of mucosal healing in Crohn's disease is an evolving treatment target. We evaluated histologic outcomes for mirikizumab efficacy and associations with endoscopic and 1-year outcomes.

METHODS

Biopsy specimens from 1 ileal and 4 colonic segments were evaluated at weeks 0, 12, and 52 from each of the 170 SERENITY participants. Criteria for the weeks 12 and 52 histologic response were no epithelial neutrophils or epithelial damage, or >50% decrease in either the Robarts Histopathology Index or the active Global Histologic Disease Activity Score, and remission (no mucosal neutrophils and no epithelial damage) had to be met in all biopsy specimens. Agreement was evaluated between histologic and endoscopic end points. Associations between 1-year outcomes and week 12 histologic and endoscopic response were evaluated.

RESULTS

At week 12, 1000 mg mirikizumab resulted in greater rates of histologic response (66% vs 27%; P < .001) and remission (26% vs 6%; P < .01) than placebo. Rates were numerically similar at 1 year (mirikizumab pooled response, 46%-69%; remission, 13%-31%). Agreement between week 12 histologic and endoscopic response was 69% (Cohen's kappa coefficient [κ] = 0.40) and remission was 83% (κ = 0.38) in all pooled arms, including placebo. At 1 year, the percentage of participants who received any dose of mirikizumab and achieved endoscopic remission differed by their week 12 response: histologic (20%), endoscopic (25%), combined histology-endoscopy (45%), or neither (4%) (P = .003).

CONCLUSIONS

In a post hoc analysis of phase 2 data, mirikizumab induced and sustained histologic response and remission in Crohn's disease over 52 weeks. Early combined histologic-endoscopic response was associated with endoscopic remission after 1 year of treatment with mirikizumab (ClinicalTrials.gov NCT02891226).

Density of Biopsy Sampling Required to Ensure Accurate Histological Assessment of Inflammation in Active Ulcerative Colitis

BACKGROUND

Histological response to treatment is an important outcome in patients with ulcerative colitis (UC). The accuracy of biopsy-based measurements of inflammation may be limited by error imposed by natural microscopic heterogeneity on the scale of individual biopsies. We determined the magnitude of this error, its histological correlates, and the density of biopsy sampling within mucosal regions of interest required to meet specified benchmarks for accuracy.

METHODS

A total of 994 sequential 1-mm digital microscopic images (virtual biopsies) from consecutive colectomies from patients with clinically severe UC were scored by 2 pathologists. Agreement statistics for Geboes subscores and Nancy (NHI) and Robarts Histological Indices (RHI) between random samples from 1 to 10 biopsies and a reference mean score across a 2-cm region of mucosa were calculated using bootstrapping with 2500 iterations.

RESULTS

The agreement statistics improved across all indices as the biopsy density increased, with the largest proportional gains occurring with addition of the second and third biopsies. One biopsy achieved moderate to good agreement with 95% confidence for NHI and RHI corresponding to scale-specific errors of 0.40 (0.25-0.66) and 3.02 (2.08-5.36), respectively; and 3 biopsies achieved good agreement with 95% confidence corresponding to scale-specific errors of 0.22 (0.14-0.39) and 1.87 (1.19-3.25), respectively. Of the individual histological features, erosions and ulcers had the greatest impact on the agreement statistics.

CONCLUSIONS

In the setting of active colitis, up to 3 biopsy samples per region of interest may be required to overcome microscopic heterogeneity and ensure accurate histological grading.

Molecular mechanisms in colitis-associated colorectal cancer

Sustained chronic inflammation of the large intestine leads to tissue damage and repair, which is associated with an increased incidence of colitis-associated colorectal cancer (CAC). The genetic makeup of CAC is somewhat similar to sporadic colorectal carcinoma (sCRC), but there are differences in the sequence and timing of alterations in the carcinogenesis process. Several models have been developed to explain the development of CAC, particularly the "field cancerization" model, which proposes that chronic inflammation accelerates mutagenesis and selects for the clonal expansion of phenotypically normal, pro-tumorigenic cells. In contrast, the "Big Bang" model posits that tumorigenic clones with multiple driver gene mutations emerge spontaneously. The details of CAC tumorigenesis-and how they differ from sCRC-are not yet fully understood. In this Review, we discuss recent genetic, epigenetic, and environmental findings related to CAC pathogenesis in the past five years, with a focus on unbiased, high-resolution genetic profiling of non-dysplastic field cancerization in the context of inflammatory bowel disease (IBD).

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

The clinical management of patients with dysplasia in chronic inflammatory bowel disease (IBD) is currently guided by Riddell et al.'s grading system (negative, indefinite, low grade, high grade) from 1983 which was based primarily on nuclear cytoarchitectural characteristics. Although most dysplasia in IBD resembles sporadic adenomas morphologically, other distinctive potential cancer precursors in IBD have been described over time. Recognizing the need for a updated comprehensive classification for IBD-associated dysplasia, an international working group of pathologists with extensive clinical and research experience in IBD devised a new classification system and assessed its reproducibility by having each participant assess test cases selected randomly from a repository of electronic images of potential cancer precursor lesions. The new classification system now encompasses three broad categories and nine sub-categories: 1) intestinal dysplasia (tubular/villous adenoma-like, goblet cell deficient, crypt cell, traditional serrated adenoma-like, sessile serrated lesion-like and serrated NOS), 2) gastric dysplasia (tubular/villous and serrated), and 3) mixed intestinal-gastric dysplasia. In the interobserver analysis, 67% of the diagnoses were considered definitive and achieved substantial inter-rater agreement. The key distinctions between intestinal and gastric lesions and between serrated and non-serrated lesions achieved substantial and moderate inter-rater agreement overall, respectively, however, the distinctions among certain serrated sub-categories achieved only fair agreement. Based on the Riddell grading system, definite dysplasia accounted for 86% of the collective responses (75% low grade, 11% high grade). Based on these results, this new classification of dysplasia in IBD can provide a sound foundation for future clinical and basic IBD research.

Aberrant p53 expression is associated with neoplastic progression in Barrett oesophagus diagnosed as indefinite for dysplasia

The aim of this study was to investigate the role of immunohistochemical (IHC) expression of p53 and other potential clinical parameters as prognostic markers for predicting neoplastic progression in Barrett oesophagus (BE) patients diagnosed as indefinite for dysplasia (IND). The study included patients with established BE of any extent who had a diagnosis of IND accompanied by concurrent p53 immunohistochemistry (IHC) stain at the index endoscopic procedure and at least one follow-up examination between 2000 and 2021. Correlation between disease progression from IND to higher-grade dysplasia [low-grade dysplasia (LGD), high-grade dysplasia (HGD) and oesophageal adenocarcinoma (EAC)] and clinicopathological parameters were analysed. A total of 149 patients (99 males; mean age 63.3 ± 10.0 years, range = 35-89) were included in the final analysis. Median follow-up was 37.1 months [interquartile range (IQR) = 20.5-59.1 months]. Progression rates from IND to LGD and HGD were 12.1% (18 of 149) and 2.7% (four of 149), respectively. On multivariate analysis, the number of IND diagnoses was significantly associated with progression to both LGD and HGD (P = 0.016 and P < 0.001, respectively). Cox regression analysis showed that aberrant p53 expression was significantly associated with progression to LGD [hazard ratio (HR) = 4.87, 95% confidence interval (CI) = 1.91-12.45, P = 0.001] and HGD (HR = 21.81, 95% CI = 1.88-253.70, P = 0.014). Kaplan-Meier survival analysis also demonstrated that aberrant p53 expression was significantly associated with progression to LGD (P < 0.001) and HGD (P = 0.001). Our results suggest that frequency of IND diagnoses and status of p53 expression can help to stratify risk of neoplastic progression in BE patients with IND.

Colorectal Strictures in Patients With Inflammatory Bowel Disease Do Not Independently Predict Colorectal Neoplasia

BACKGROUND

Colorectal strictures have been considered independent risk factors for neoplasia in patients with inflammatory bowel disease (IBD). We examined the association between colorectal stricture and subsequent risk of colorectal neoplasia (CRN) in patients with IBD colitis undergoing colonoscopic surveillance.

METHODS

We conducted a retrospective cohort analysis of patients with IBD colitis enrolled in colonoscopic surveillance for CRN at an academic medical center between 2005 and 2017. Inclusion criteria were IBD involving the colon for ≥8 years (or any duration with primary sclerosing cholangitis [PSC]) undergoing surveillance. Exclusion criteria were advanced CRN (ACRN; colorectal cancer [CRC] or high-grade dysplasia [HGD]) prior to or at enrollment, prior colectomy, or limited (<30%) disease extent or proctitis. Multivariable logistic and Cox regression analysis estimated the association between colorectal stricture on the index colonoscopy and ACRN, CRN (indefinite dysplasia, low-grade dysplasia, HGD, CRC), or colectomy.

RESULTS

Among 789 patients with IBD undergoing CRC surveillance, 72 (9%; 70 with Crohn's colitis) had a colorectal stricture on index colonoscopy. There was no significant difference in the frequency of ACRN or requirement for colectomy between patients with vs without a colorectal stricture (P > .05). Colorectal stricture was not associated with subsequent ACRN (adjusted odds ratio [aOR], 1.41; 95% CI, 0.49-4.07), CRN (aOR, 1.15; 95% CI, 0.51-2.58), or colectomy (aOR, 1.10; 95% CI, 0.65-1.84).

CONCLUSIONS

In this analysis of patients with IBD colitis undergoing CRN surveillance, the presence of a colorectal stricture was not independently associated with risk of ACRN or colectomy. Multicenter, prospective studies are needed to confirm these findings, particularly in patients with ulcerative colitis-associated colorectal stricture.

Constrictive and Hypertrophic Strictures in Ileal Crohn's Disease

BACKGROUND & AIMS

Strictures in Crohn's disease (CD) are classically attributed to fibromuscular hypertrophy of the intestinal wall. We have identified and characterized CD-related ileal strictures that result instead from mural constriction (ie, reduced external circumference).

METHODS

Twenty-four strictures and internal controls from 17 adults with obstructive CD were analyzed by cross-sectional morphometry.

RESULTS

The stricture-to-control circumference ratios (CRs) ranged from 0.53 to 1.7. Six strictures with CR ≥1.0, designated hypertrophic, had concentrically thickened walls, mean 3-fold increases in cross-sectional area and stainable fibromucular tissue, and high transmural inflammation scores. In contrast, 18 strictures with CR <1.0, designated constrictive, had thin, pliant walls, cross-sectional areas and stainable fibromuscular tissue comparable with control values, and low transmural inflammation scores. Eight mildly constrictive strictures also showed mild fibromuscular mural expansion that fell short of statistical significance. Twelve of 18 constrictive strictures (67%) occurred multiply (2-4 strictures per specimen) in contrast with hypertrophic strictures, all of which occurred singly (P = .01). Constriction correlated quantitatively with circumferential serosal fat wrapping (P = .003) and was associated with myenteric lymphocytic plexitis (P = .02). Disease duration was shortest among subjects with constrictive strictures and correlated with increasing circumference (CR ≤0.8, 6.3 ± 6.2 years; CR >0.8, 8.7 ± 6.4 years; and CR ≥1.00, 13.7 ± 5.0 years, respectively; P = .03).

CONCLUSIONS

Constrictive ileal strictures in CD differ pathologically and clinically from hypertrophic strictures, featuring little or no fibromuscular mural expansion, frequent multiplicity, and earlier onset. Mesenteric fat wrapping and myenteric plexitis may contribute to their pathogenesis. Pathologic manifestations of constriction and hypertrophy can coexist, suggesting that stricture heterogeneity may be shaped in part by the dynamics of constrictive and hypertrophic processes.

Baseline Histological Findings Do Not Predict the Risk of Subsequent Extension in Patients with Limited Ulcerative Colitis

BACKGROUND

Among patients with limited ulcerative colitis (UC), 30% ultimately extend to pancolitis and are at increased risk of adverse clinical outcomes. Risk of endoscopic extension has been found to correlate with clinical features such as early age of onset.

AIMS

We sought to determine whether histologic features correlate with disease extension.

METHODS

The study population consisted of 40 patients with UC from two large academic centers diagnosed between 2006 and 2017. Eligible cases had a diagnosis of endoscopically limited UC (Montreal E1 or E2) at baseline and ≥ 2 subsequent endoscopic examinations with biopsies. Severity of inflammation was scored using both the Mount Sinai Activity Index and Nancy Histological Index.

RESULTS

Patients were divided into two cohorts: those who progressed to pancolitis (Montreal E3) were defined as "Extenders" (n = 21), whereas "Non-extenders" (n = 19) were cases without progression in the follow-up period. The median follow-up time was 58.4 months. The histologic scores in the endoscopically involved mucosa of the index biopsies were not associated with subsequent extension of disease, overall. However, among extender cohort, the index histology scores correlated with biopsy scores at extension (r = 0.455, P = 0.044) and index severity was associated with a shorter time to extension (r =  - 0.611, P = 0.003). Furthermore, female patients had a shorter time to extension (P = 0.013).

CONCLUSIONS

Histological severity of limited UC is not an independent predictor of extension in UC. However, among patients who subsequently extend, severe inflammation at baseline correlates with shorter progression time and severe inflammation when extension occurs. Patients with limited UC but severe histologic inflammation may warrant more frequent endoscopic surveillance.

International consensus to standardise histopathological scoring for small bowel strictures in Crohn's disease

OBJECTIVE

Effective medical therapy and validated trial outcomes are lacking for small bowel Crohn's disease (CD) strictures. Histopathology of surgically resected specimens is the gold standard for correlation with imaging techniques. However, no validated histopathological scoring systems are currently available for small bowel stricturing disease. We convened an expert panel to evaluate the appropriateness of histopathology scoring systems and items generated based on panel opinion.

DESIGN

Modified RAND/University of California Los Angeles methodology was used to determine the appropriateness of 313 candidate items related to assessment of CD small bowel strictures.

RESULTS

In this exercise, diagnosis of naïve and anastomotic strictures required increased bowel wall thickness, decreased luminal diameter or internal circumference, and fibrosis of the submucosa. Specific definitions for stricture features and technical sampling parameters were also identified. Histopathologically, a stricture was defined as increased thickness of all layers of the bowel wall, fibrosis of the submucosa and bowel wall, and muscularisation of the submucosa. Active mucosal inflammatory disease was defined as neutrophilic inflammation in the lamina propria and any crypt or intact surface epithelium, erosion, ulcer and fistula. Chronic mucosal inflammatory disease was defined as crypt architectural distortion and loss, pyloric gland metaplasia, Paneth cell hyperplasia, basal lymphoplasmacytosis, plasmacytosis and fibrosis, or prominent lymphoid aggregates at the mucosa/submucosa interface. None of the scoring systems used to assess CD strictures were considered appropriate for clinical trials.

CONCLUSION

Standardised assessment of gross pathology and histopathology of CD small bowel strictures will improve clinical trial efficiency and aid drug development.

Whole Slide Imaging for Teleconsultation: The Mount Sinai Hospital, Labcorp Dianon, and Philips Collaborative Experience

Background:

With the emergence of whole slide imaging (WSI) and widespread access to high-speed Internet, pathology labs are now poised to implement digital pathology as a way to access diagnostic pathology expertise. This paper describes a collaborative partnership between a high-volume reference diagnostic laboratory (Labcorp) and an academic pathology department (Mount Sinai Hospital) in the transition from a traditional glass slide service to a digital platform. Using the standard framework of implementation science, we evaluate the consistency and quality of the Philips IntelliSite Pathology Solution (PIPS) in delivering save and efficient diagnostic services.

Materials and Methods:

Digital and glass slide diagnoses of all consult cases were documented over a 12-month period. The Proctor guideline was used to quantitatively and qualitatively measure (e.g., focus group studies, field notes, and administrative data) implementation success. Lean techniques (e.g., value stream mapping) were applied to measure changes in efficiency with the transition to a digital platform.

Results:

Our study supports the acceptability, high adoption, appropriateness, feasibility, fidelity, and sustainability of the digital pathology platform. The digital portal also improved the quality of patient care by increasing efficiency, effectiveness, safety, and timeliness. The intraobserver concordance rate was 100%. The digital transition resulted in a reduction in turnaround time from 86 h to an average 35 min and a 20-fold increase in efficiency of the consultation process.

Conclusion:

As the pathology community contemplates digital pathology as a transformational tool in providing broad access to diagnostic expertise across time and space, our study provides an implementation strategy along with evidence that the digital platform is safe, effective, and efficient.

The association between pre-colectomy thiopurine use and risk of neoplasia after ileal pouch anal anastomosis in patients with ulcerative colitis or indeterminate colitis: a propensity score analysis

BACKGROUND

The risk of neoplasia of the pouch or residual rectum in patients with ulcerative colitis (UC) who undergo total proctocolectomy (TPC) with ileal pouch anal anastomosis (IPAA) is incompletely investigated. Thiopurine use is associated with a reduced risk of colorectal neoplasia in patients with UC. We tested the hypothesis that thiopurine use prior to TPC may be associated with a reduced risk of primary neoplasia after IPAA.

METHODS

We conducted a retrospective cohort analysis of patients from a tertiary referral center from January 2008 to December 2017. Eligible patients with UC or IC underwent TPC with IPAA and had at least two pouchoscopies with biopsies ≥ 6 months after surgery. Propensity score analysis was conducted to match thiopurine exposed vs unexposed groups based on clinical covariates. Multivariable Cox regression analysis estimated the risk of neoplasia.

RESULTS

A total of 284 patients with UC or IC (57.4% male, median age 35.6 years) were analyzed. Ninety-seven patients (34.2%) were confirmed to have thiopurine exposure ≥ 12 weeks immediately prior to TPC ("exposed") and 187 (65.8%) were confirmed to have no thiopurine exposure for at least 365 days prior to TPC ("non-exposed"). Compared to non-exposed patients, patients with thiopurine exposure less often had dysplasia (7.2% vs 23.0%, p = 0.001) and had lower grades of dysplasia before colectomy. After IPAA, patients with neoplasia were older (44.0 vs 34.8 years, p = 0.03), more likely to have had dysplasia as colectomy indication (44.4% vs 15.4%, p = 0.007), and more likely to require pouch excision (55.6% vs 10.2%, p < 0.0001), compared to patients without neoplasia. On propensity-matched cohort analysis, no factors were significantly associated with risk of primary neoplasia.

CONCLUSION

Thiopurine exposure for at least the 12 weeks prior to TPC in patients with UC or IC does not appear to be independently associated with risk of primary neoplasia following IPAA.

Impact of pathological response after neoadjuvant chemotherapy on adjuvant therapy decisions and patient outcomes in gastrointestinal cancers

BACKGROUND

Neoadjuvant chemotherapy (NAC) is frequently used in gastrointestinal cancers (GIC), and pathological, radiological, and tumor marker responses are assessed during and after NAC.

AIM

To evaluate the relationship between pathologic, radiologic, tumor marker responses and recurrence-free survival (RFS), overall survival (OS), adjuvant chemotherapy (AC) decisions, and the impact of changing to a different AC regimen after poor response to NAC.

METHODS AND RESULTS

Medical records of GIC patients treated with NAC at Mount Sinai between 1/2012 and 12/2018 were reviewed. One hundred fifty-six patients (58.3% male, mean age 63 years) were identified. Primary tumor sites were: 43 (27.7%) pancreas, 62 (39.7%) gastroesophageal, and 51 (32.7%) colorectal. After NAC, 31 (19.9%) patients had favorable pathologic response (FPR; defined as College of American Pathologists [CAP] score 0-1). Of 107 patients with radiological data, 59 (55.1%) had an objective response, and of 113 patients with tumor marker data, 61 (54.0%) had a ≥50% reduction post NAC. FPR, but not radiographic or serological responses, was associated with improved RFS (HR 0.28; 95% CI 0.11-0.72) and OS (HR 0.13; 95% CI 0.2-0.94). Changing to a different AC regimen from initial NAC, among all patients and specifically among those with unfavorable pathological response (UPR; defined as CAP score 2-3) after NAC, was not associated with improved RFS or OS.

CONCLUSIONS

GIC patients with FPR after NAC experienced significant improvements in RFS and OS. Patients with UPR did not benefit from changing AC. Prospective studies to better understand the role of pathological response in AC decisions and outcomes in GIC patients are needed.

Molecular Characterization of Limited Ulcerative Colitis Reveals Novel Biology and Predictors of Disease Extension

BACKGROUND AND AIMS

Disease extent varies in ulcerative colitis (UC) from proctitis to left-sided colitis to pancolitis and is a major prognostic factor. When the extent of UC is limited there is often a sharp demarcation between macroscopically involved and uninvolved areas and what defines this or subsequent extension is unknown. We characterized the demarcation site molecularly and determined genes associated with subsequent disease extension.

METHODS

We performed RNA sequence analysis of biopsy specimens from UC patients with endoscopically and histologically confirmed limited disease, of which a subset later extended. Biopsy specimens were obtained from the endoscopically inflamed upper (proximal) limit of disease, immediately adjacent to the uninvolved colon, as well as at more proximal, endoscopically uninflamed colonic segments.

RESULTS

Differentially expressed genes were identified in the endoscopically inflamed biopsy specimens taken at each patient's most proximal diseased site relative to healthy controls. Expression of these genes in the more proximal biopsy specimens transitioned back to control levels abruptly or gradually, the latter pattern supporting the concept that disease exists beyond the endoscopic disease demarcation site. The gradually transitioning genes were associated with inflammation, angiogenesis, glucuronidation, and homeodomain pathways. A subset of these genes in inflamed biopsy specimens was found to predict disease extension better than clinical features and were responsive to biologic therapies. Network analysis revealed critical roles for interferon signaling in UC inflammation and poly(ADP-ribose) polymerase 14 (PARP14) was a predicted key driver gene of extension. Higher PARP14 protein levels were found in inflamed biopsy specimens of patients with limited UC that subsequently extended.

CONCLUSION

Molecular predictors of disease extension reveal novel strategies for disease prognostication and potential therapeutic targeting.

Luminal Narrowing Alone Allows an Accurate Diagnosis of Crohn's Disease Small Bowel Strictures at Cross-Sectional Imaging

BACKGROUND AND AIMS

Current consensus recommendations define small bowel strictures [SBS] in Crohn's disease [CD] on imaging as luminal narrowing with unequivocal upstream bowel dilation. The aim of this study was to [1] evaluate the performance of cross-sectional imaging for SBS diagnosis in CD using luminal narrowing with upstream SB dilation and luminal narrowing with or without upstream dilation, and [2] compare the diagnostic performance of computed tomography [CT] and magnetic resonance enterography [MRE] for SBS diagnosis.

METHODS

In total, 111 CD patients [81 with pathologically confirmed SBS, 30 controls] who underwent CT and/or MRE were assessed. Two radiologists [R1, R2] blinded to pathology findings independently assessed the presence of luminal narrowing and upstream SB dilation. Statistical analysis was performed for [1] luminal narrowing with or without SB upstream dilation ['possible SBS'], and [2] luminal narrowing with upstream SB dilation ≥3 cm ['definite SBS'].

RESULTS

Sensitivity for detecting SBS was significantly higher using 'possible SBS' [R1, 82.1%; R2, 77.9%] compared to 'definite SBS' [R1, 62.1%; R2, 65.3%; p < 0.0001] with equivalent specificity [R1, 96.7%; R2, 93.3%; p > 0.9]. Using the criterion 'possible SBS', sensitivity/specificity were equivalent between CT [R1, 87.3%/93.3%; R2, 83.6%/86.7%] and MRE [R1, 75.0%/100%; R2: 70.0%/100%]. Using the criterion 'definite SBS', CT showed significantly higher sensitivity [78.2%] compared to MRE [40.0%] for R1 but not R2 with similar specificities [CT, 86.7-93.3%; MRE, 100%].

CONCLUSION

SBS can be diagnosed using luminal narrowing alone without the need for upstream dilation. CT and MRE show similar diagnostic performance for SBS diagnosis using luminal narrowing with or without upstream dilation.

An International Consensus to Standardize Integration of Histopathology in Ulcerative Colitis Clinical Trials

BACKGROUND & AIMS

Histopathology is an emerging treatment target in ulcerative colitis (UC) clinical trials. Our aim was to provide guidance on standardizing biopsy collection protocols, identifying optimal evaluative indices, and defining thresholds for histologic response and remission after treatment.

METHODS

An international, interdisciplinary expert panel of 19 gastroenterologists and gastrointestinal pathologists was assembled. A modified RAND/University of California, Los Angeles appropriateness methodology was used to address relevant issues. A total of 138 statements were derived from a systematic review of the literature and expert opinion. Each statement was anonymously rated as appropriate, uncertain, or inappropriate using a 9-point scale. Survey results were reviewed and discussed before a second round of voting.

RESULTS

Histologic measurements collected using a uniform biopsy strategy are important for assessing disease activity and determining therapeutic efficacy in UC clinical trials. Multiple biopsy strategies were deemed acceptable, including segmental biopsies collected according to the endoscopic appearance. Biopsies should be scored for architectural change, lamina propria chronic inflammation, basal plasmacytosis, lamina propria and epithelial neutrophils, epithelial damage, and erosions/ulcerations. The Geboes score, Robarts Histopathology Index, and Nancy Index were considered appropriate for assessing histologic activity; use of the modified Riley score and Harpaz Index were uncertain. Histologic activity at baseline should be required for enrollment, recognizing this carries operational implications. Achievement of histologic improvement or remission was considered an appropriate and realistic therapeutic target. Current histologic indices require validation for pediatric populations.

CONCLUSIONS

These recommendations provide a framework for standardized implementation of histopathology in UC trials. Additional work is required to address operational considerations and areas of uncertainty.

Intestinal Host Response to SARS-CoV-2 Infection and COVID-19 Outcomes in Patients With Gastrointestinal Symptoms

BACKGROUND & AIMS

Given that gastrointestinal (GI) symptoms are a prominent extrapulmonary manifestation of COVID-19, we investigated intestinal infection with SARS-CoV-2, its effect on pathogenesis, and clinical significance.

METHODS

Human intestinal biopsy tissues were obtained from patients with COVID-19 (n = 19) and uninfected control individuals (n = 10) for microscopic examination, cytometry by time of flight analyses, and RNA sequencing. Additionally, disease severity and mortality were examined in patients with and without GI symptoms in 2 large, independent cohorts of hospitalized patients in the United States (N = 634) and Europe (N = 287) using multivariate logistic regressions.

RESULTS

COVID-19 case patients and control individuals in the biopsy cohort were comparable for age, sex, rates of hospitalization, and relevant comorbid conditions. SARS-CoV-2 was detected in small intestinal epithelial cells by immunofluorescence staining or electron microscopy in 15 of 17 patients studied. High-dimensional analyses of GI tissues showed low levels of inflammation, including down-regulation of key inflammatory genes including IFNG, CXCL8, CXCL2, and IL1B and reduced frequencies of proinflammatory dendritic cells compared with control individuals. Consistent with these findings, we found a significant reduction in disease severity and mortality in patients presenting with GI symptoms that was independent of sex, age, and comorbid illnesses and despite similar nasopharyngeal SARS-CoV-2 viral loads. Furthermore, there was reduced levels of key inflammatory proteins in circulation in patients with GI symptoms.

CONCLUSIONS

These data highlight the absence of a proinflammatory response in the GI tract despite detection of SARS-CoV-2. In parallel, reduced mortality in patients with COVID-19 presenting with GI symptoms was observed. A potential role of the GI tract in attenuating SARS-CoV-2-associated inflammation needs to be further examined.

Intestinal Inflammation Modulates the Expression of ACE2 and TMPRSS2 and Potentially Overlaps With the Pathogenesis of SARS-CoV-2-related Disease

BACKGROUND AND AIMS

The presence of gastrointestinal symptoms and high levels of viral RNA in the stool suggest active severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication within enterocytes.

METHODS

Here, in multiple, large cohorts of patients with inflammatory bowel disease (IBD), we have studied the intersections between Coronavirus Disease 2019 (COVID-19), intestinal inflammation, and IBD treatment.

RESULTS

A striking expression of ACE2 on the small bowel enterocyte brush border supports intestinal infectivity by SARS-CoV-2. Commonly used IBD medications, both biologic and nonbiologic, do not significantly impact ACE2 and TMPRSS2 receptor expression in the uninflamed intestines. In addition, we have defined molecular responses to COVID-19 infection that are also enriched in IBD, pointing to shared molecular networks between COVID-19 and IBD.

CONCLUSIONS

These data generate a novel appreciation of the confluence of COVID-19- and IBD-associated inflammation and provide mechanistic insights supporting further investigation of specific IBD drugs in the treatment of COVID-19. Preprint doi: https://doi.org/10.1101/2020.05.21.109124.

Gastrointestinal involvement attenuates COVID-19 severity and mortality

Given that gastrointestinal (GI) symptoms are a prominent extrapulmonary manifestation of coronavirus disease 2019 (COVID-19), we investigated intestinal infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and its effect on disease pathogenesis. SARS-CoV-2 was detected in small intestinal enterocytes by immunofluorescence staining or electron microscopy, in 13 of 15 patients studied. High dimensional analyses of GI tissues revealed low levels of inflammation in general, including active downregulation of key inflammatory genes such as IFNG, CXCL8, CXCL2 and IL1B and reduced frequencies of proinflammatory dendritic cell subsets. To evaluate the clinical significance of these findings, examination of two large, independent cohorts of hospitalized patients in the United States and Europe revealed a significant reduction in disease severity and mortality that was independent of gender, age, and examined co-morbid illnesses. The observed mortality reduction in COVID-19 patients with GI symptoms was associated with reduced levels of key inflammatory proteins including IL-6, CXCL8, IL-17A and CCL28 in circulation but was not associated with significant differences in nasopharyngeal viral loads. These data draw attention to organ-level heterogeneity in disease pathogenesis and highlight the role of the GI tract in attenuating SARS-CoV-2-associated inflammation with related mortality benefit.

One Sentence Summary

Intestinal infection with SARS-CoV-2 is associated with a mild inflammatory response and improved clinical outcomes.

Upper Gastrointestinal Manifestations of Inflammatory Bowel Disease

Although the features of lower gastrointestinal tract inflammation associated with ulcerative colitis and Crohn disease are generally familiar to pathologists, there is less awareness of and familiarity with the manifestations of inflammatory bowel disease in the esophagus, stomach, and duodenum. Nonetheless, their diagnosis has therapeutic and possibly prognostic implications, potentially foretelling severe complications. The recognition that ulcerative colitis can affect gastrointestinal organs proximal to the large intestine and terminal ileum represents a revision of concepts ingrained among generations of physicians. This article reviews the pathologic features and clinical significance of esophagitis, gastritis, and duodenitis associated with inflammatory bowel disease.

Collagenous Colitis Is Associated With HLA Signature and Shares Genetic Risks With Other Immune-Mediated Diseases

BACKGROUND & AIMS

Collagenous colitis (CC) is an inflammatory bowel disorder with unknown etiopathogenesis involving HLA-related immune-mediated responses and environmental and genetic risk factors. We carried out an array-based genetic association study in a cohort of patients with CC and investigated the common genetic basis between CC and Crohn's disease (CD), ulcerative colitis (UC), and celiac disease.

METHODS

DNA from 804 CC formalin-fixed, paraffin-embedded tissue samples was genotyped with Illumina Immunochip. Matching genotype data on control samples and CD, UC, and celiac disease cases were provided by the respective consortia. A discovery association study followed by meta-analysis with an independent cohort, polygenic risk score calculation, and cross-phenotype analyses were performed. Enrichment of regulatory expression quantitative trait loci among the CC variants was assessed in hemopoietic and intestinal cells.

RESULTS

Three HLA alleles (HLA-B∗08:01, HLA-DRB1∗03:01, and HLA-DQB1∗02:01), related to the ancestral haplotype 8.1, were significantly associated with increased CC risk. We also identified an independent protective effect of HLA-DRB1∗04:01 on CC risk. Polygenic risk score quantifying the risk across multiple susceptibility loci was strongly associated with CC risk. An enrichment of expression quantitative trait loci was detected among the CC-susceptibility variants in various cell types. The cross-phenotype analysis identified a complex pattern of polygenic pleiotropy between CC and other immune-mediated diseases.

CONCLUSIONS

In this largest genetic study of CC to date with histologically confirmed diagnosis, we strongly implicated the HLA locus and proposed potential non-HLA mechanisms in disease pathogenesis. We also detected a shared genetic risk between CC, celiac disease, CD, and UC, which supports clinical observations of comorbidity.

Ileocolic anastomotic inflammation after resection for Crohn's disease indicates disease recurrence: a histopathologic study

Objectives: We performed a pathological pilot study to characterize the inflammation at the ileocolic anastomosis as Crohn's disease or ischemia.Methods and materials: Subjects were selected at random from a retrospective database of patients with Crohn's disease and who had undergone an ileocolic resection with subsequent endoscopic assessment of the anastomosis and neo-terminal ileum. Pathology slides from the anastomotic mucosa, either from targeted biopsies or subsequent ileocolic resections, were re-assessed histologically for features of ischemia and of Crohn's disease.Results: Twenty-nine specimens from 8 patients were reviewed, including 12 ileocolic resection specimens and 17 sets of endoscopic biopsies. Twenty-seven of the 29 specimens, accounting for all of the patients, had evidence of CD-like features. In contrast, only 2 specimens, accounting for 2 of 8 patients, had histologic features of ischemia, and both specimens also had Crohn's-like features.Conclusion: To our knowledge this is the first study to specifically evaluate the pathology of ileocolic anastomoses in Crohn's disease. It suggests that anastomotic inflammation is predominantly a manifestation of recurrent Crohn's disease rather than of postoperative ischemia.

Association Between Indefinite Dysplasia and Advanced Neoplasia in Patients With Inflammatory Bowel Diseases Undergoing Surveillance

BACKGROUND & AIMS

Little is known about the clinical significance of indefinite dysplasia (IND) in patients with inflammatory bowel diseases (IBD) undergoing colonoscopic surveillance for colorectal neoplasia.

METHODS

We conducted a retrospective cohort analysis of 492 patients with colonic IBD for 8 or more years or concomitant primary sclerosing cholangitis, with no history of advanced colorectal neoplasia (high-grade dysplasia or colorectal cancer) or colectomy, undergoing colorectal neoplasia surveillance at a tertiary IBD referral center from 2001 through 2017. Subjects received consistent histopathologic grading of dysplasia. We collected data on time to development of (advanced) colorectal neoplasia or colectomy using Kaplan Meier methods. We identified factors independently associated with (advanced) colorectal neoplasia with multivariable Cox regression analysis.

RESULTS

After 2149 person-years of follow-up, 53 patients (10.8%) received a diagnosis of IND without prior or synchronous low-grade dysplasia (LGD). Compared to patients without dysplasia, patients with IND had a significantly higher risk of advanced colorectal neoplasia (adjusted hazard ratio, 6.85; 95% CI, 1.78-26.4) and colorectal neoplasia (adjusted hazard ratio, 3.25; 95% CI, 1.50-7.05), but not colectomy (P = .78). Compared to IND, LGD was associated with a significantly higher risk of advanced colorectal neoplasia (P = .05). Following a diagnosis of no dysplasia, IND only, or LGD, the incidence rates of advanced colorectal neoplasia were 0.4% per patient-year, 3.1% per patient-year, and 8.4% per patient-year, respectively.

CONCLUSIONS

In a retrospective analysis of patients with IBD undergoing colorectal neoplasia surveillance with consistent histopathologic grading of dysplasia, IND was independently associated with a significant increase in risk of advanced colorectal neoplasia. These findings require validation and if confirmed, a reappraisal of the colorectal neoplasia surveillance guidelines.

Clinicopathological and Molecular Characterisation of Crohn's Disease-associated Small Bowel Adenocarcinomas

BACKGROUND AND AIMS

Small bowel adenocarcinoma [SBA] is a recognised complication of Crohn's disease [CD], but its low absolute prevalence limits opportunities for clinicopathological characterisation.

METHODS

We compared the clinical, pathological, and molecular features of 48 SBA from patients with CD [CDSBA] and 29 SBAs from patients without CD [NSBA] who underwent treatment at our tertiary care centre between 2000 and 2018.

RESULTS

Patients with CDSBA were younger than those with NSBA [mean age, 56 vs 64; p = 0.02]. Males predominated in both groups. Most CDSBA [69%] occurred in the ileum, whereas most NSBA occurred in the duodenum [38%] and jejunum [31%; p < 0.001]. Stage I tumours were more prevalent in the CDSBA [33% vs 3%; p = 0.002], although the rates of Stage IV disease and disease-specific mortality were similar in both groups. CDSBA were less likely to present a discrete mass [35% vs 93%; p < 0.001] and were more often stricturing or fistulising [75% vs 10%, respectively, p < 0.001] than NSBA. Microscopically, CDSBA were relatively heterogeneous, exhibiting at least three distinct growth patterns in 39% compared with 1% of NSBA [p = 0.01]. Low-grade tubuloglandular adenocarcinoma was the predominant pattern in 19% of CDSBA compared with 0% of NSBA [p = 0.003]. CDSBA were more frequently DNA mismatch repair proficient [90% vs 62%; p = 0.04] and exhibited profiles of frequently mutated genes similar to those of NSBA, except for IDH1 [18%] and SMAD4 [12%] mutations that occurred uniquely in CDSBA.

CONCLUSIONS

These observations, based on the largest single-centre series described hitherto, establish that CDSBA is a distinct clinical, pathological, and molecular entity.

Histopathology Scoring Systems of Stenosis Associated With Small Bowel Crohn's Disease: A Systematic Review

BACKGROUND & AIMS

Stenosis is a common complication of Crohn's disease (CD) that has no effective medical therapy. Development of antifibrotic agents will require testing in randomized controlled trials. Computed tomography enterography- and magnetic resonance enterography-based technologies might be used to measure outcomes in these trials. These approaches have been validated in studies of patients with symptomatic strictures who underwent imaging evaluations followed by resection with histopathologic grading of the intestinal tissue for inflammation and/or fibrosis (the reference standard). Imaging findings have correlated with findings from quantitative or semiquantitative histologic evaluation of the degree of fibromuscular stenosis and/or inflammation on the resection specimen. However, it is not clear whether histologic findings are an accurate reference standard. We performed a systematic review of all published histologic scoring systems used to assess stenosing CD.

METHODS

We performed a comprehensive search of Embase and MEDLINE of studies through March 13, 2019, that used a histologic scoring system to characterize small bowel CD and assessed inflammatory and fibrotic alterations within the same adult individual. All scores fitting the criteria were included in our analysis, independent of the presence of stricturing disease, as long as inflammation and fibrosis were evaluated separately but in the same scoring system.

RESULTS

We observed substantial heterogeneity among the scoring systems, which were not derived from modern principles for evaluative index development. None had undergone formal validity or reliability testing. None of the existing indices had been constructed according to accepted methods for the development of evaluative indices. Basic knowledge regarding their operating properties were lacking. Specific indices for evaluating the important pathologic component of myofibroblast hypertrophy or hyperplasia have not been proposed.

CONCLUSIONS

In a systematic review of publications, we found a lack of validated histopathologic scoring systems for assessment of fibromuscular stenosis. Data that describe the operating properties of existing cross-sectional imaging techniques for stenosing CD should be questioned. Development and validation of a histopathology index is an important research priority.

Mutation profile of high-grade appendiceal mucinous neoplasm

AIMS

High-grade appendiceal mucinous neoplasm (HAMN) was recently proposed as a disease entity histologically analogous to low-grade appendiceal mucinous neoplasm (LAMN), but characterised by high-grade cytological atypia. The pathogenesis and clinical features of HAMN have not been fully elucidated.

METHODS AND RESULTS

Nine cases of HAMN, eight LAMN, 10 appendiceal mucinous adenocarcinomas (MACA) and five appendiceal serrated polyps resected between 2008 and 2017 contributed by three medical centres underwent targeted next-generation sequencing of 50 cancer-related genes. The patients in each category had similar profiles with respect to gender, age, tumour stage and follow-up intervals. Both LAMN and HAMN harboured mutations of KRAS [nine of nine and eight of eight (100%), respectively] and GNAS [five of eight (63%) and five of nine (56%), respectively] in significantly higher proportions than MACA [KRAS, seven of 10 (70%, P = 0.04); GNAS: one of 10 (10%, P = 0.02)] and serrated polyps [KRAS, one of five (20%, P = 0.0007); GNAS: none of five (0%, P = 0.04)]. Four cases of HAMN, but none of LAMN, harboured mutations of TP53 [four of nine (44%)] and/or ATM [two of nine (22%)]. Three cases of HAMN (33%) showed extra-appendiceal spread with retention of the same mutational profiles in the intra- and extra-appendiceal components. The 10 cases of MACA harboured a similar prevalence of TP53 mutations (n = 5, 50%) as HAMN but, unlike LAMN and HAMN, some harboured mutations in PIK3CA, APC, FBXW7, PTEN and SMAD4.

CONCLUSIONS

HAMN and LAMN share high rates of KRAS and GNAS co-mutations supporting a common histogenesis and distinguishing them from MACA. Acquisition of TP53 or ATM mutations by HAMN may drive its progression to a more advanced phenotype.

Expression Profiling of Inflammatory and Immunological Genes in Collagenous Colitis

BACKGROUND

Collagenous colitis [CC] is a common idiopathic cause of chronic watery diarrhoea. We investigated its pathogenesis by means of gene expression analysis.

METHODS

We analysed the expression of genes implicated in immunological and inflammatory pathways in paired colonic biopsies of histologically involved and uninvolved mucosa from five patients with histologically patchy CC, in pooled colonic biopsies of eight other patients with diffuse CC, and in pooled biopsies of eight normal controls. Analyses were performed with the Nanostring nCounter system. Expression ratios were generated and confirmed by quantitative reverse transcription PCR.

RESULTS

CC mucosa was characterized by enhanced expression of nitric oxide synthase 2; of matrix metalloproteinases 3 and 9 and tissue inhibitor of metalloproteinase 1, but not transforming growth factor β1; of mediators of T-helper 1 immunity including interleukins 12A [IL12A], 12B, IL12 receptor B1 and interferon γ; of immune mediators of the leukocyte immunoglobulin-like receptor subfamily B; and of multiple T cell cytokines and their receptors. The mitogen-activated protein kinase signalling pathway was unchanged. There were no increases in IL22, IL22RA2 or tumour necrosis factor α, which are reportedly elevated in chronic inflammatory bowel disease. In four of five patients with patchy CC, similar gene expression profiles were observed in histologically involved and uninvolved mucosa.

CONCLUSIONS

CC is characterized by altered expression of a limited repertoire of genes involved in nitric oxide synthesis, extracellular matrix remodelling, T-helper 1 immunity and immune modulation. The abnormal gene expression in patchy CC may be expressed in mucosa with and without histological disease manifestations.

Clinicopathological characterization of SMAD4-mutated intestinal adenocarcinomas: A case-control study

The SMAD4 tumor suppressor gene product inhibits transforming growth factor-β-mediated signaling and is mutated in ~10% of colorectal carcinomas. The prognostic significance of SMAD4 mutations has been controversial. We studied the pathological and clinical characteristics of SMAD4-mutated intestinal adenocarcinomas using a retrospective case-control study design. Cases and controls were identified among 443 primary adenocarcinomas that had undergone next generation DNA sequencing (NGS) with the Ion AmpliSeq Cancer Hotspot Panel v2, which evaluates 50 cancer-related genes. Twenty-eight SMAD4-mutated (SMAD4m) patients were matched 1:2 with 56 consecutive SMAD4 wild-type (SMAD4wt) control patients from the same analysis stream. Compared with the SMAD4wt controls, the SMAD4m tumors were of higher stage (P = 0.026) and were more likely to feature mucinous differentiation (P = 0.0000), to occur in the setting of Crohn’s disease (P = 0.0041), and to harbor concurrent RAS mutations (P = 0.0178). Tumor mucin content was significantly correlated with mutations involving the MH2 domain of the SMAD4 protein (P = 0.0338). Correspondence between mutation sites and morphology was demonstrated directly in a mixed adenocarcinoma and neuroendocrine tumor where SMAD4 mutations involving different protein domains were found in histologically disparate tumor regions despite both containing identical KRAS and TP53 mutations.

Isolated Gastric Metastasis of Endometrial Adenocarcinoma: First Case Report and Review of Pertinent Literature

Upper gastrointestinal metastasis of endometrial carcinoma rarely occurs in the absence of locoregional disease and other distant metastases. We describe herein the unique case of an isolated gastric metastasis of a stage I endometrial adenocarcinoma. Because the metastatic tumor was initially misdiagnosed clinically and pathologically as a primary gastric carcinoma, we illustrate the histopathology and review the pertinent literature. A 42-year-old woman with Lynch syndrome underwent treatment of endometrial adenocarcinoma at an outside hospital comprising clinical and radiological staging including a positron emission tomography-computed tomography (PET-CT) scan followed by a total intra-abdominal hysterectomy, bilateral salpingoophorectomy and pelvic and paraaortic lymphadenectomy. The preoperative and pathology findings were consistent with a stage I tumor. Three months postoperatively, a PET-CT scan revealed a new 4.4 cm hypermetabolic lesion in the stomach. A biopsy of the lesion was interpreted pathologically as gastric adenocarcinoma with lymphoid stroma. Upon referral of the patient to our center for management, the biopsy was reviewed in consultation and the pathology materials from the hysterectomy procedure were retrieved for comparison. Based on the morphological and immunohistochemical similarities between the tumors the gastric tumor was diagnosed as metastatic endometrial adenocarcinoma. To our knowledge, this is the first documented case of an isolated gastric metastasis complicating stage I endometrial adenocarcinoma. Awareness of the potential for this occurrence and of the associated diagnostic pitfalls is crucial for accurate diagnosis and therapy.

SATB2 and Hep Par 1 Immunohistochemistry Is Helpful in Distinguishing Between Inflamed and Architecturally Altered Ileal Pouch and Rectal Cuff Mucosa

The management of patients with ulcerative colitis after proctocolectomy with ileal pouch-anal anastomosis includes independent histological assessments of inflammation in the ileal pouch and the rectal cuff. However, the distinction between pouchitis and cuffitis can be impeded both endoscopically and histologically by the combined effects of inflammation and regeneration. We investigated the use of 2 markers, hepatocyte paraffin 1 (Hep) and SATB2 (special AT-rich sequence-binding protein 2), which are expressed immunohistochemically in the small and large bowel epithelium, respectively, as ancillary methods to deal with this problem. Immunohistochemical staining was performed retrospectively on 20 consecutive pairs of post-ileal pouch-anal anastomosis biopsies with varying degrees of histological inflammation and architectural distortion, which had each been designated as "ileal pouch" or "rectal cuff" by the referring endoscopists. Expression was graded as focal (10% to 74% stained cells) or diffuse (75% to 100%). Among the ileal pouch biopsies, 20 (100%) expressed Hep either diffusely (75%) or focally (25%), whereas SATB2 staining was either negative in 15 (75%) or focal in 5 (25%), the latter group all expressing Hep diffusely. Among the rectal cuff biopsies, 14 expressed SATB2 diffusely. Of these, Hep was either negative in 11 (79%) or focally positive in 3 (21%), the latter group all expressing SATB2 diffusely. Six ostensibly rectal cuff biopsies (30%) expressed Hep diffusely and were negative for SATB2, suggesting endoscopic misidentification. None of the 40 biopsies expressed both markers diffusely. We conclude that in doubtful cases, diffuse expression of either Hep or SATB2 can be helpful in discriminating between ileal pouch and rectal cuff mucosa, respectively.

High Risk of Advanced Colorectal Neoplasia in Patients With Primary Sclerosing Cholangitis Associated With Inflammatory Bowel Disease

BACKGROUND & AIMS

Patients with inflammatory bowel disease (IBD) and primary sclerosing cholangitis (PSC, termed PSC-IBD) are at increased risk for colorectal cancer, but their risk following a diagnosis of low-grade dysplasia (LGD) is not well described. We aimed to determine the rate of advanced colorectal neoplasia (aCRN), defined as high-grade dysplasia and/or colorectal cancer, following a diagnosis of indefinite dysplasia or LGD in this population.

METHODS

We performed a retrospective, longitudinal study of 1911 patients with colonic IBD (293 with PSC and 1618 without PSC) who underwent more than 2 surveillance colonoscopies from 2000 through 2015 in The Netherlands or the United States (9265 patient-years of follow-up evaluation). We collected data on clinical and demographic features of patients, as well as data from each surveillance colonoscopy and histologic report. For each surveillance colonoscopy, the severity of active inflammation was documented. The primary outcome was a diagnosis of aCRN during follow-up evaluation. We also investigated factors associated with aCRN in patients with or without a prior diagnosis of indefinite dysplasia or LGD.

RESULTS

Patients with PSC-IBD had a 2-fold higher risk of developing aCRN than patients with non-PSC IBD. Mean inflammation scores did not differ significantly between patients with PSC-IBD (0.55) vs patients with non-PSC IBD (0.56) (P = .89), nor did proportions of patients with LGD (21% of patients with PSC-IBD vs 18% of patients with non-PSC IBD) differ significantly (P = .37). However, the rate of aCRN following a diagnosis of LGD was significantly higher in patients with PSC-IBD (8.4 per 100 patient-years) than patients with non-PSC IBD (3.0 per 100 patient-years; P = .01). PSC (adjusted hazard ratio [aHR], 2.01; 95% CI, 1.09-3.71), increasing age (aHR 1.03; 95% CI, 1.01-1.05), and active inflammation (aHR, 2.39; 95% CI, 1.63-3.49) were independent risk factors for aCRN. Dysplasia was more often endoscopically invisible in patients with PSC-IBD than in patients with non-PSC IBD.

CONCLUSIONS

In a longitudinal study of almost 2000 patients with colonic IBD, PSC remained a strong independent risk factor for aCRN. Once LGD is detected, aCRN develops at a higher rate in patients with PSC and is more often endoscopically invisible than in patients with only IBD. Our findings support recommendations for careful annual colonoscopic surveillance for patients with IBD and PSC, and consideration of colectomy once LGD is detected.

Magnetic Resonance Imaging Predicts Histopathological Composition of Ileal Crohn's Disease

BACKGROUND AND AIMS

Recently, smooth muscle hypertrophy has been suggested to be a contributor to small bowel lesions secondary to Crohn's disease [CD], in addition to inflammation and fibrosis. Here, we assess the value of magnetic resonance imaging [MRI] for the characterisation of histopathological tissue composition of small bowel CD, including inflammation, fibrosis, and smooth muscle hypertrophy.

METHODS

A total of 35 consecutive patients [male/female 17/18, mean age 33 years] with ileal CD, who underwent small bowel resection and a preoperative contrast-enhanced MRI examination within 1 month before surgery, were retrospectively included. Image assessment included qualitative [pattern/degree of enhancement, presence of ulcerations/fistulas/abscesses] and quantitative parameters [wall thickness on T2/T1-weighted images [WI], enhancement ratios, apparent diffusion coefficient [ADC], Clermont and Magnetic Resonance Index of Activity [MaRIA] scores). MRI parameters were compared with histopathological findings including active inflammation, collagen deposition, and muscle hypertrophy using chi square/Fisher or Mann-Whitney tests and univariate/multivariate logistic/linear regression analyses.

RESULTS

Forty ileal segments were analysed in 35 patients. Layered pattern at early-post-contrast phase was more prevalent (odds ratio [OR] = 8; p = 0.008), ADC was significantly lower [OR = 0.005; p = 0.022], and MaRIA score was significantly higher [OR = 1.125; p = 0.022] in inflammation grades 2-3 compared with grade 1. Wall thickness on T2WI was significantly increased [OR = 1.688; p = 0.043], and fistulas [OR = 14.5; p = 0.017] were more prevalent in segments with disproportionately increased muscle hypertrophy versus those with disproportionately increased fibrosis. MaRIA/Clermont scores, wall thickness on T1WI and T2WI, and ADC were all significantly correlated with degree of muscular hypertrophy.

CONCLUSIONS

MRI predicts the degree of inflammation, and can distinguish prominent muscle hypertrophy from prominent fibrosis in ileal CD with reasonable accuracy (area under receiver operating characteristic curve [AUROC] > 0.7).

Effect of Helicobacter pylori infection on outcomes in resected gastric and gastroesophageal junction cancer

BACKGROUND

Helicobacter pylori (H pylori) infection is a known risk factor for gastric cancer (GC) and has been linked with gastroesophageal junction (GEJ) cancer. Studies examining the relationship between H. pylori infection, GC characteristics and prognosis are limited and have yielded conflicting results. We report on the clinicopathologic characteristics and oncologic outcomes of gastric and GEJ cancer patients with and without a history of H. pylori treated at our institution.

METHODS

We retrospectively reviewed the medical records of patients over the age of 18 years who underwent curative resection for GEJ and GC at Mount Sinai Hospital between 2007 and 2012 who had histopathologic documentation of the presence or absence of H pylori infection. Demographic, clinical, pathologic, treatment characteristics and outcomes including recurrence-free survival (RFS) and overall survival (OS) were compared.

RESULTS

Ninety-five patients were identified. The majority of patients were male (61%), white (36%) or Asian (34%), with median age at diagnosis 64. Tumors were stage I (51%), stage II (23%), stage III (25%), and stage IV (1%). H pylori infection status was documented at the time of cancer diagnosis in 89 (94%) patients, and following cancer diagnosis and treatment in 6 (6%) patients. Younger age at diagnosis, Asian race and Lauren histologic classification were associated with H Pylori infection. H pylori positive patients exhibited higher 5-year OS and 5-year RFS compared to H pylori negative patients, though the difference was not statistically significant in either univariate or multivariate analyses.

CONCLUSIONS

In this retrospective series of predominantly early stage GC and GEJ cancers, H. pylori positive patients were significantly younger at cancer diagnosis and were more frequently Asian compared to H. pylori negative patients. Other demographic and histologic classifications except for Lauren histologic classification were similar between the two groups. H pylori positive patients appeared to have improved outcomes compared to H. pylori negative patients.

Chemotherapy Tolerance and Oncologic Outcomes in Patients With Colorectal Cancer With and Without Inflammatory Bowel Disease

BACKGROUND

Inflammatory bowel disease (IBD), comprising Crohn disease and ulcerative colitis, is a risk factor for colorectal cancer (CRC). Chemotherapy toxicity may exacerbate IBD symptoms and vice versa, but data are limited. We evaluated chemotherapy tolerance and oncologic outcomes in patients with CRC with and without IBD.

PATIENTS AND METHODS

Medical records of patients with CRC with and without IBD treated between 2008 and 2013 were reviewed. Where possible, patients were matched by age, sex, stage, and diagnosis year. Chemotherapy tolerance and survival outcomes were compared between patients with IBD and without IBD.

RESULTS

A total of 158 subjects with CRC were included: 80 patients had IBD and 78 matched control patients did not have IBD. Between cases and controls, there were no significant differences in demographic data, stage of CRC, and cancer treatments, with equivalent numbers of patients receiving surgery, radiation, and chemotherapy. Patients with IBD experienced more CRC treatment alterations than those without IBD (74% vs. 44%, P = .03), largely due to a higher frequency of treatment delays among patients with IBD. Differences in stage-specific 5-year overall survival (OS) and recurrence-free survival (RFS) in patients with and without IBD were not significant, except for stage IV patients with IBD who had significantly shorter OS than those without IBD. Patients with histologically active IBD did not require more chemotherapy alterations than patients with inactive IBD.

CONCLUSION

In this series, patients with CRC with IBD experienced more treatment alterations (mostly delays) than those without IBD. Patients with stage IV CRC with IBD had shorter survival than patients without IBD.

Gastrointestinal Autonomic Nerve Tumor of the Colon

Gastrointestinal autonomic nerve tumor (GANT) is an uncommon subtype of gastrointestinal stromal tumor that is morphologically similar to conventional stromal tumors but has ultrastructural features of neural differentiation. Of the approximately 58 cases of GANT reported to date, most have arisen in the small intestine or stomach, but none, to our knowledge, in the colon or rectum. Accordingly, we report the first case of colonic GANT and document its histologic, ultrastructural, and immunohistochemical characteristics. These were not unlike those of GANT arising elsewhere in the alimentary tract, including interlacing spindle cells, skenoid fibers, axonal cytoplasmic processes, dense core neurosecretory granules, and immunoreactivity to vimentin and NSE. The rarity of GANT in the large intestine should not preclude ultrastructural evaluation of colorectal stromal tumors for neural features.

Chromoendoscopy Is More Effective Than Standard Colonoscopy in Detecting Dysplasia During Long-term Surveillance of Patients With Colitis

BACKGROUND & AIMS

Patients with colitis have an increased risk of colorectal cancer, compared with persons without colitis. Many studies have shown chromoendoscopy (CE) to be superior to standard methods of detecting dysplasia in patients with colitis at index examination. We performed a prospective, longitudinal study to compare standard colonoscopy vs CE in detecting dysplasia in patients with inflammatory bowel diseases in a surveillance program.

METHODS

We analyzed data from 68 patients (44 men, 24 women) diagnosed with ulcerative colitis (n = 55) or Crohn's disease (n = 13) at Mount Sinai Medical Center from September 2005 through October 2011. The patients were followed from June 2006 through October 2011 (median, 27.8 months); each patient was analyzed by random biopsy, targeted white light examination (WLE), and CE. Specimens were reviewed by a single blinded pathologist. The 3 methods were compared by using the generalized estimating equations method, and the odds ratios (ORs) for detection of dysplasia were calculated (primary outcome). Time to colectomy was analyzed by using the Cox model.

RESULTS

In the 208 examinations conducted, 44 dysplastic lesions were identified in 24 patients; 6 were detected by random biopsy, 11 by WLE, and 27 by CE. Ten patients were referred for colectomy, and no carcinomas were found. At any time during the study period, CE (OR, 5.4; 95% confidence interval [CI], 2.9-9.9) and targeted WLE (OR, 2.3; 95% CI, 1.0-5.3) were more likely than random biopsy analysis to detect dysplasia. CE was superior to WLE (OR, 2.4; 95% CI, 1.4-4.0). Patients identified as positive for dysplasia were more likely to need colectomy (hazard ratio, 12.1; 95% CI, 3.2-46.2).

CONCLUSIONS

In a prospective study of 68 patients with inflammatory bowel diseases, CE was superior to random biopsy or WLE analyses in detecting dysplasia in patients with colitis during an almost 28-month period. A negative result from CE examination was the best indicator of a dysplasia-free outcome, whereas a positive result was associated with earlier referral for colectomy.

Overexpression of α1 chain of type XI collagen (COL11A1) aids in the diagnosis of invasive carcinoma in endoscopically removed malignant colorectal polyps

INTRODUCTION

The histologic distinction between benign misplaced adenomatous mucosa and invasive adenocarcinoma in colorectal polyps can be challenging. The α1 chain of type XI collagen (COL11A1) has been shown to be overexpressed in cancer-associated stromal fibroblasts. The aim of this study was to investigate the operating characteristics of COL11A1 immunostaining in benign and malignant colorectal polyps as a potential diagnostic aid.

MATERIALS AND METHODS

Sixty-six endoscopically-removed paraffin-embedded colorectal polyps were stained with anti-COL11A1 antibody. They comprised 50 malignant polyps (MPs) with invasive adenocarcinoma (including 5 with concurrent benign misplaced adenomatous mucosa) and 16 adenomas, 11 with and 5 without benign misplaced adenomatous mucosa.

RESULTS

COL11A1 was expressed either diffusely or focally in cancer-associated desmoplastic fibroblasts in 72.0% (36/50) of MPs. The rates of COL11A1 expression and the immunohistochemical staining patterns of the COL11A1 were positively correlated with the depth of cancer invasion in MPs. COL11A1 was expressed in all 9 (100%) MPs with a mucinous component and in 16/18 (88.9%) MPs associated with significant electrocautery effects. COL11A1 was not expressed adjacent to conventional adenomas or in the stroma adjacent to misplaced adenomatous mucosa.

CONCLUSIONS

COL11A1 antibody can assist in distinguishing the cancer-associated desmoplastic stroma from that associated with misplaced adenomatous mucosa. It is particularly helpful when electrocautery artifacts or mucin pools interfere with the diagnosis of invasive carcinoma. However, COL11A1 has limited value in diagnosing superfically invasive carcinomas with very little desmoplastic stroma due to its low positive rate and focal expression in some cases.

Reproducibility of histological assessments of disease activity in UC

OBJECTIVE

Histopathology is potentially an important outcome measure in UC. Multiple histological disease activity (HA) indices, including the Geboes score (GS) and modified Riley score (MRS), have been developed; however, the operating properties of these instruments are not clearly defined. We assessed the reproducibility of existing measures of HA.

DESIGN

Five experienced pathologists with GI pathology fellowship training and expertise in IBD evaluated, on three separate occasions at least two weeks apart, 49 UC colon biopsies and scored the GS, MRS and a global rating of histological severity using a 100 mm visual analogue scale (VAS). The reproducibility of each grading system and for individual instrument items was quantified by estimates of intraclass correlation coefficients (ICCs) based on two-way random effects models. Uncertainty of estimates was quantified by 95% two-sided CIs obtained using the non-parametric cluster bootstrap method. Biopsies responsible for the greatest disagreement based on the ICC estimates were identified. A consensus process was used to determine the most common sources of measurement disagreement. Recommendations for minimising disagreement were subsequently generated.

RESULTS

Intrarater ICCs (95% CIs) for the total GS, MRS and VAS scores were 0.82 (0.73 to 0.88), 0.71 (0.63 to 0.80) and 0.79 (0.72 to 0.85), respectively. Corresponding inter-rater ICCs were substantially lower: 0.56 (0.39 to 0.67), 0.48 (0.35 to 0.66) and 0.61 (0.47 to 0.72). Correlation between the GS and VAS was 0.62 and between the MRS and VAS was 0.61.

CONCLUSIONS

Although 'substantial' to 'almost perfect' ICCs for intrarater agreement were found in the assessment of HA in UC, ICCs for inter-rater agreement were considerably lower. According to the consensus process results, standardisation of item definitions and modification of the existing indices is required to create an optimal UC histological instrument.

Neurogenic polyps of the gastrointestinal tract: a clinicopathologic review with emphasis on differential diagnosis and syndromic associations

Primary neurogenic gastrointestinal polyps are encountered relatively frequently in routine pathology practice. They encompass a variety of neoplastic entities with clinical, morphologic, and molecular features that reflect the diversity of neural elements within the gastrointestinal system. Although most are benign and encountered incidentally, accurate diagnosis may have important clinical implications because of the associations of certain neurogenic polyps with familial syndromes or other conditions. We review the pathology of these polyps with an emphasis on the diagnostic challenges that they pose and on newly described subtypes.

IL-23 activates innate lymphoid cells to promote neonatal intestinal pathology

Interleukin-23 (IL-23) responsive group 3 innate lymphoid cells (ILC3s) have been implicated in immune homeostasis and pathogenesis in the adult, but little is known about their roles in the newborn. Here we show that IL-23 promotes conversion of embryonic intestinal Lin(-)IL-23R(+)Thy1(+) cells into IL-22-producing Thy1(+)Sca-1(hi) ILC3s in vitro. Gut-specific expression of IL-23 also activated and expanded Thy1(+)Sca-1(hi) ILC3s, which produced IL-22, IL-17, interferon gamma (IFN-γ), and granulocyte-macrophage colony-stimulating factor (GM-CSF) and were distinct from canonical CD4(+) lymphoid tissue inducer (LTi) cells. These ILC3s accumulated under the epithelium in intercellular adhesion molecule (ICAM)-1-positive cell aggregates together with neutrophils that disrupted the epithelium, leading to the formation of discrete intestinal erosions, bleeding, and neonatal death. Genetic and antibody depletion of ILC3s rescued the mice from neonatal death. Antibiotic treatment of pregnant mothers and offspring prolonged survival of IL-23 transgenic mice, suggesting a role for the commensal flora on ILC3-induced pathogenesis. Our results reveal a novel role for the IL-23-ILC3s axis in the pathogenesis of neonatal intestinal inflammation.

Prognostic significance of lymph node metastases in small intestinal neuroendocrine tumors

BACKGROUND/AIMS

Current staging guidelines for small intestinal neuroendocrine tumors (SI-NETs) differentiate between the presence (N1) and absence (N0) of lymph node (LN) metastases. However, the prognostic significance of the extent of LN involvement remains unknown. In this study, we used data from a population-based cancer registry to examine whether involvement of a higher number of LNs is associated with worse survival.

METHODS

We used the Surveillance, Epidemiology, and End Results (SEER) database to identify patients with histologically confirmed, surgically resected SI-NETS diagnosed between 1988 and 2010. Patients were classified into three groups by the LN ratio (number of positive LNs/number of total LNs examined, LNR): ≤0.2, >0.2-0.5, and >0.5. We used the Kaplan-Meier method and Cox models to assess NET cancer-specific survival differences (up to 10 years from diagnosis) according to LNR status.

RESULTS

We identified 2,984 surgically resected patients with stage IIIb (N1, M0) SI-NETs with detailed LN data. More than half of the NETs were located in the ileum. A higher LNR was significantly associated with worse NET cancer-specific survival (p < 0.0001). Ten-year NET-specific survival was 85, 77, and 74% for patients in the ≤0.2, >0.2-0.5, and >0.5 LNR groups, respectively. In stratified analyses, higher LNR groups had worse survival only in early tumor (T1, T2) disease (p < 0.0001).

CONCLUSIONS

The extent of LN involvement provides independent prognostic information on patients with LN-positive SI-NETs. This information may be used to identify patients at high risk of recurrence and inform decisions about the use of adjuvant therapy.