How could pathologists improve the initial diagnosis of colitis? Evidence from an international workshop

Rapid Endoscopic Diagnosis of Benign Ulcerative Colorectal Diseases With an Artificial Intelligence Contextual Framework

BACKGROUND & AIMS

Benign ulcerative colorectal diseases (UCDs) such as ulcerative colitis, Crohn's disease, ischemic colitis, and intestinal tuberculosis share similar phenotypes with different etiologies and treatment strategies. To accurately diagnose closely related diseases like UCDs, we hypothesize that contextual learning is critical in enhancing the ability of the artificial intelligence models to differentiate the subtle differences in lesions amidst the vastly divergent spatial contexts.

METHODS

White-light colonoscopy datasets of patients with confirmed UCDs and healthy controls were retrospectively collected. We developed a Multiclass Contextual Classification (MCC) model that can differentiate among the mentioned UCDs and healthy controls by incorporating the tissue object contexts surrounding the individual lesion region in a scene and spatial information from other endoscopic frames (video-level) into a unified framework. Internal and external datasets were used to validate the model's performance.

RESULTS

Training datasets included 762 patients, and the internal and external testing cohorts included 257 patients and 293 patients, respectively. Our MCC model provided a rapid reference diagnosis on internal test sets with a high averaged area under the receiver operating characteristic curve (image-level: 0.950 and video-level: 0.973) and balanced accuracy (image-level: 76.1% and video-level: 80.8%), which was superior to junior endoscopists (accuracy: 71.8%, P < .0001) and similar to experts (accuracy: 79.7%, P = .732). The MCC model achieved an area under the receiver operating characteristic curve of 0.988 and balanced accuracy of 85.8% using external testing datasets.

CONCLUSIONS

These results enable this model to fit in the routine endoscopic workflow, and the contextual framework to be adopted for diagnosing other closely related diseases.

Duodenal Crohn's disease: Case report and systematic review

BACKGROUND

Inflammatory bowel disease, including ulcerative colitis, microscopic colitis, and Crohn's disease (CD), has a global impact. This review focuses on duodenal CD (DCD), a rare subtype affecting the duodenum. DCD's rarity and asymptomatic nature create diagnostic challenges, impacting prognosis and patient well-being. Delayed diagnosis can worsen DCD outcomes.

AIM

To report a rare case of DCD and to discuss the diagnostic challenges and its implications on prognosis.

METHODS

A systematic literature search, following the PRISMA statement, was conducted. Relevant studies were identified and analysed using specific Medical Subject Terms (MeSH) from PubMed/MEDLINE, American Journal of Gastroenterology, and the University of South Wales database. Data collection included information from radiology scans, endoscopy procedures, biopsies, and histopathology results.

RESULTS

The review considered 8 case reports and 1 observational study, involving 44 participants diagnosed with DCD, some of whom developed complications due to delayed diagnosis. Various diagnostic methods were employed, as there is no gold standard workup for DCD. Radiology scans [magnetic resonance imaging (MRI), computed tomography (CT), and upper gastrointestinal X-ray], endoscopy procedures (colonoscopy and esophagogastroduodenoscopy), biopsies, and clinical suspicions were utilized.

CONCLUSION

This review discusses DCD diagnosis challenges and the roles of CT, MRI, and fluoroscopy. It notes their limitations and compares findings with endoscopy and histopathology studies. Further research is needed to improve diagnosis, emphasizing scan interpretation, endoscopy procedures, and biopsies, especially in high-risk patients during routine endoscopy.

OralEpitheliumDB: A Dataset for Oral Epithelial Dysplasia Image Segmentation and Classification

Early diagnosis of potentially malignant disorders, such as oral epithelial dysplasia, is the most reliable way to prevent oral cancer. Computational algorithms have been used as an auxiliary tool to aid specialists in this process. Usually, experiments are performed on private data, making it difficult to reproduce the results. There are several public datasets of histological images, but studies focused on oral dysplasia images use inaccessible datasets. This prevents the improvement of algorithms aimed at this lesion. This study introduces an annotated public dataset of oral epithelial dysplasia tissue images. The dataset includes 456 images acquired from 30 mouse tongues. The images were categorized among the lesion grades, with nuclear structures manually marked by a trained specialist and validated by a pathologist. Also, experiments were carried out in order to illustrate the potential of the proposed dataset in classification and segmentation processes commonly explored in the literature. Convolutional neural network (CNN) models for semantic and instance segmentation were employed on the images, which were pre-processed with stain normalization methods. Then, the segmented and non-segmented images were classified with CNN architectures and machine learning algorithms. The data obtained through these processes is available in the dataset. The segmentation stage showed the F1-score value of 0.83, obtained with the U-Net model using the ResNet-50 as a backbone. At the classification stage, the most expressive result was achieved with the Random Forest method, with an accuracy value of 94.22%. The results show that the segmentation contributed to the classification results, but studies are needed for the improvement of these stages of automated diagnosis. The original, gold standard, normalized, and segmented images are publicly available and may be used for the improvement of clinical applications of CAD methods on oral epithelial dysplasia tissue images.

The Histology-Driven Differential Diagnosis in Bowel Inflammatory Conditions Is Not All That Obvious: Evidence from a Survey Based on Digital Slides

(1) Background: when the pathologist faces histologic slides from colonoscopies in daily practice, given the large number of entities and etiologies under inflammatory bowel conditions, in-depth definition of the histological spectrum and the recommendations of current guidelines are often not enough to conclusively define a diagnostic framework. Histological patterns should be organized hierarchically in flowcharts that consider the correlation with clinical data. We conducted an online survey asking a group of gastroenteropathologists to apply a pattern classification based on the most significant lesions in colitis differential diagnosis: crypt distortion and activity. (2) Methods: digital slides from 20 endoscopy samples were analyzed by twenty pathologists and classified according to the occurrence of crypt distortion (nondestructive-destructive colitis) and subsequently to the evidence of activity (ND1-2-3, D1-2). (3) Results: in 8 out of 20 (40%) cases, the participants reached a full agreement regarding the evaluation of crypt distortion (5 cases: nondestructive colitis; 3 cases: destructive colitis). The calculated agreement was k = 0.432. In the second-level quiz (ND1-2-3 and D1-2), full agreement between participants was achieved for 7 of the 28 (25%) possible classifications, with k = 0.229. (4) Conclusions: The findings from this survey are indicative of an unexpectedly low consensus, even among dedicated pathologists, about the recognition of histological changes that are commonly considered critical lesions in the histologic identification of bowel non-neoplastic diseases. In our opinion, these divergences imply a significant risk of misdiagnosis of bowel inflammatory conditions, hampering the usefulness of histological assessment.

Therapeutic Effects of Aloe saponaria against Ulcerative Colitis Induced by Dextran Sulfate Sodium

Aloe vera (A. vera) has been studied as a treatment option for ulcerative colitis (UC), but there is a lack of scientific evidence showing whether treatment with Aloe saponaria (A. saponaria) can also be beneficial. To investigate the therapeutic potential of A. saponaria as a treatment for UC, clinical symptoms, histopathological characteristics of the colon, inflammatory response, and toxicity were analyzed in dextran sulfate sodium (DSS)-induced UC mice after administration of aqueous extracts of A. saponaria (AAS) for 7 days. The total polyphenol and tannin content of AAS was 272 µg/g and 163 µg/g, respectively. AAS exhibited significant antioxidant activity. Several clinical symptoms, including body weight, colon length, and hematochezia, remarkably improved in the DSS+AAS treated group compared to the DSS+Vehicle-treated group. In addition, similar improvements were detected in the histopathological characteristics and mucin-secreting ability in the colon of DSS-induced UC mice after the administration of AAS. The levels of infiltrated inflammatory cells and cytokine expression were significantly decreased in a dose-dependent manner in the colon of the DSS+AAS-treated group. These alterations in inflammatory response were accompanied by a significant recovery of the protein kinase C/extracellular signal-regulated kinase (PKC/ERK) and phosphatidylinositol-3-kinase/serine-threonine protein kinase (PI3K/Akt) signaling pathways. However, the levels of key markers for hepatotoxicity and nephrotoxicity consistently remained between those of the DSS+AAS-treated and the No groups. Therefore, the results of the present study provide novel evidence that AAS may improve the clinical symptoms and attenuate the inflammatory response in DSS-induced UC mice and does not have any significant hepatotoxicity or nephrotoxicity.

The Role of Magnetic Resonance Enterography in Crohn’s Disease: A Review of Recent Literature

Inflammatory bowel disease (IBD) is the term used to identify a form of chronic inflammation of the gastrointestinal tract that primarily contemplates two major entities: ulcerative colitis (UC) and Crohn’s disease (CD). The classic signs are abdominal pain and diarrhoea that correlate with the localization of gastro-enteric disease, although in this pathology extraintestinal symptoms may coexist. The diagnosis of CD relies on a synergistic combination of clinical, laboratory (stool and biochemical), cross-sectional imaging evaluation, as well as endoscopic and histologic assessments. The purpose of this paper is to prove the role of imaging in the diagnosis and follow-up of patients with CD with particular focus on recent innovations of magnetic resonance enterography (MRE) as a pivotal diagnostic tool, analysing the MRE study protocol and imaging features during the various phases of disease activity and its complications.

Sampling and Reporting of Inflammatory Bowel Disease

Pathologists have an important and expanding role in the diagnosis and management of inflammatory bowel disease. This role includes the initial diagnosis of the disease, assessment of the response to treatment and the identification of short-term complications such as cytomegalovirus infection and long-term complications such as dysplasia. Furthermore, the assessment of resection specimens for complication of disease is important to determining the risk of subsequent disease or inflammation within an ileal pouch. Adequate sampling of the disease at endoscopy and from the surgical resection specimen is vital to determining the ultimate information that can be provided by the pathologist. This sampling is determined by the clinical scenario. Similarly, a standardized approach to reporting and synthesizing the histologic findings will improve patient management. This is best exemplified by the increasing interest in histologic activity indices, such as the Nancy index in ulcerative colitis, and in the standardized reporting for inflammatory bowel disease dysplasia recommended by the SCENIC international consensus.

Inflammatory bowel disease position statement of the Italian Society of Colorectal Surgery (SICCR): Crohn's disease

The Italian Society of Colorectal Surgery (SICCR) promoted the project reported here, which consists of a position statement of Italian colorectal surgeons to address the surgical aspects of Crohn's disease management. Members of the society were invited to express their opinions on several items proposed by the writing committee, based on evidence available in the literature. The results are presented, focusing on relevant points. The present paper is not an alternative to available guidelines; rather, it offers a snapshot of the attitudes of SICCR surgeons about the surgical treatment of Crohn's disease. The committee was able to identify some points of major disagreement and suggested strategies to improve quality of available data and acceptance of guidelines.

The role of small bowel endoscopy for Crohn's disease

PURPOSE OF REVIEW

The review discusses the roles of small bowel capsule endoscopy and deep enteroscopy in patients with Crohn's disease. It highlights recent advances in the field and identifies areas where evidence is lacking.

RECENT FINDINGS

Small bowel capsule endoscopy has an important role in the follow-up of patients with Crohn's disease after escalation of therapy and in the postoperative assessment period following surgical resection. Device-assisted enteroscopy offers the therapeutic advantage of small bowel dilatation, which may result in a reduction in the number of surgical resections required, thus avoiding long-term complications, such as short bowel syndrome and malabsorption.

SUMMARY

Capsule endoscopy has an established role in the diagnosis and management of small bowel Crohn's disease. It is used in the setting of suspected Crohn's disease when ileocolonoscopy is negative and for the assessment of extent of small bowel disease in established Crohn's disease. It is relatively well tolerated because of the provision of patency capsule endoscopy to minimize the risk of inadvertent capsule retention. Device-assisted enteroscopy aids with the diagnosis of Crohn's disease as it enables histology to be taken from inflamed areas within the small bowel. Therapeutic procedures can be carried out during device-assisted enteroscopy including dilatation of Crohn's disease-related strictures and retrieval of retained capsules.

Reporting Colonic Biopsies in Patients With Inflammatory Bowel Disease; a Practical Approach

Crohn's disease (CD) and ulcerative colitis (UC) are common diseases; for convenience, we lump them together as inflammatory bowel disease (IBD). Colonic biopsies are essential for establishing a diagnosis, monitoring treatment, and/or identifying complications. This article attempts to detail the histological criteria of UC and CD and also informs on a lifelong approach of reporting colonic biopsies from patients with IBD. Often the clinical information on the accompanying request form is not available to the pathologist. In these cases, the author has initiated a reproducible system of pattern-based reporting with a differential diagnosis. This type of report offers a working diagnosis for the clinician before the final diagnosis, which is recommended to be undertaken in a setting of combined clinico-pathological conference (CPC). This system carries objective parameters and standardizes reporting to significantly minimize the interobserver variations among reporting pathologists. If a CPC facility is not available, we offer an alternative evidence-based arrangement. We discourage the use the term "nonspecific colitis" as we have shown that it has no clinical value or agreed-upon and recognized histopathological features. As the paper addresses mucosal biopsies, the entity of indeterminate colitis will not be included in this article as this diagnosis is strictly based on colonic resectate. 10.1093/ibd/izy288_video1 izy288.video1 5839278247001.

A comprehensive review and update on ulcerative colitis. Dis Mon 2019;65:100851. [PMID: 30837080 DOI: 10.1016/j.disamonth.2019.02.004]

Ulcerative colitis (UC) is a chronic idiopathic inflammatory bowel disorder of the colon that causes continuous mucosal inflammation extending from the rectum to the more proximal colon, with variable extents. UC is characterized by a relapsing and remitting course. UC was first described by Samuel Wilks in 1859 and it is more common than Crohn's disease worldwide. The overall incidence and prevalence of UC is reported to be 1.2-20.3 and 7.6-245 cases per 100,000 persons/year respectively. UC has a bimodal age distribution with an incidence peak in the 2nd or 3rd decades and followed by second peak between 50 and 80 years of age. The key risk factors for UC include genetics, environmental factors, autoimmunity and gut microbiota. The classic presentation of UC include bloody diarrhea with or without mucus, rectal urgency, tenesmus, and variable degrees of abdominal pain that is often relieved by defecation. UC is diagnosed based on the combination of clinical presentation, endoscopic findings, histology, and the absence of alternative diagnoses. In addition to confirming the diagnosis of UC, it is also important to define the extent and severity of inflammation, which aids in the selection of appropriate treatment and for predicting the patient's prognosis. Ileocolonoscopy with biopsy is the only way to make a definitive diagnosis of UC. A pathognomonic finding of UC is the presence of continuous colonic inflammation characterized by erythema, loss of normal vascular pattern, granularity, erosions, friability, bleeding, and ulcerations, with distinct demarcation between inflamed and non-inflamed bowel. Histopathology is the definitive tool in diagnosing UC, assessing the disease severity and identifying intraepithelial neoplasia (dysplasia) or cancer. The classical histological changes in UC include decreased crypt density, crypt architectural distortion, irregular mucosal surface and heavy diffuse transmucosal inflammation, in the absence of genuine granulomas. Abdominal computed tomographic (CT) scanning is the preferred initial radiographic imaging study in UC patients with acute abdominal symptoms. The hallmark CT finding of UC is mural thickening with a mean wall thickness of 8 mm, as opposed to a 2-3 mm mean wall thickness of the normal colon. The Mayo scoring system is a commonly used index to assess disease severity and monitor patients during therapy. The goals of treatment in UC are three fold-improve quality of life, achieve steroid free remission and minimize the risk of cancer. The choice of treatment depends on disease extent, severity and the course of the disease. For proctitis, topical 5-aminosalicylic acid (5-ASA) drugs are used as the first line agents. UC patients with more extensive or severe disease should be treated with a combination of oral and topical 5-ASA drugs +/- corticosteroids to induce remission. Patients with severe UC need to be hospitalized for treatment. The options in these patients include intravenous steroids and if refractory, calcineurin inhibitors (cyclosporine, tacrolimus) or tumor necrosis factor-α antibodies (infliximab) are utilized. Once remission is induced, patients are then continued on appropriate medications to maintain remission. Indications for emergency surgery include refractory toxic megacolon, colonic perforation, or severe colorectal bleeding.

Prevalence of Mycobacterium avium subspecies paratuberculosis IS 900 DNA in biopsy tissues from patients with Crohn's disease: histopathological and molecular comparison with Johne's disease in Fars province of Iran

BACKGROUND

Crohn's disease is a chronic enteritis of humans that affects the gastrointestinal tract, especially the terminal ileum, cecum and colon. The etiology of this disease is still unknown but seems to be multifactorial. There are reports about the potential link between Crohn's disease in humans and the causative agent of Johne's disease in ruminants. Because of the prevalence of Johne's disease in the Fars Province of Iran, the aim of this study was to investigate the prevalence of MAP in the biopsy tissues of patients affected by Crohn's disease in this area.

METHODS

The study was performed from April 2015 to June 2017 at Namazi Hospital, Shiraz University of Medical Sciences, and School of Veterinary Medicine, Shiraz University, Shiraz, Iran. Intestinal biopsies of 30 patients (12 male and 18 female; mean age, 34 years; range 4-77 years) with the confirmed diagnosis of Crohn's disease and 30 patients diagnosed as non-inflammatory bowel disease (19 male and 11 female; mean age, 38 years; range 13-68 years) were studied by molecular, histopathological and histochemical methods. Also, similar numbers of adult goats affected by Johne's disease were studied, comparatively. DNA extractions of tissue specimens were subjected to PCR to amplify a 413-bp sequence of the IS900 gene.

RESULTS

Using IS900-PCR, the overall prevalence of MAP in patients affected by Crohn's disease and non-inflammatory bowel disease were 47 and 13%, respectively. In addition, the prevalence of MAP in goats affected by Johne's disease was 70%. Using acid-fast histochemical staining, only 7% of Crohn's disease patients were weakly positive as paucibacillary and 43% of Johne's disease cases were moderate to strongly positive as multibacillary. Histopathologically, granulomatous enteritis (83 and 90%), lymphoplasmacytic enteritis (17 and 14%), edema and lymphangiectasia (67 and 96%), and vasculitis (20 and 73%) were common findings in Crohn's and Johne's diseases, respectively.

CONCLUSION

Our findings demonstrate a remarkable association between MAP and CD in this population, and support an etiologic relationship between MAP infection in humans and the development of CD. MAP infection in human tissue may display species-specific pathologic findings, as occurs with other zoonotic pathogens.

THE IMPORTANCE OF COLONOSCOPY IN INFLAMMATORY BOWEL DISEASES

INTRODUCTION

Endoscopic evaluation, particularly the macroscopic mucosal and histological results of ileocolic biopsies, is essential for the management of inflammatory bowel disease. Endoscopic appearance is not always sufficient to differentiate Crohn's disease and ulcerative colitis, but there are some characteristics that favor one or another diagnosis. Both diseases have an increased incidence of colorectal carcinoma; so, surveillance colonoscopy is important for detecting early neoplastic lesions.

OBJECTIVE

To update the importance of endoscopy in the evaluation, diagnosis and prognosis of inflammatory bowel disease.

METHOD

Search was done in the scientific literature of the TRIP database, chosen from clinical questions (PICO) with the following descriptors: "inflammatory bowel disease", "endoscopy/colonoscopy", "Crohn's disease", "ulcerative colitis" and "diagnosis/treatment".

RESULTS

Endoscopic investigation in patients with chronic colitis is quite accurate for the differential diagnosis between ulcerative colitis and Crohn's disease. Endoscopy is indicated for ulcerative colitis during severe crisis due to its prognostic value. Another accepted indication for endoscopy in inflammatory bowel disease is its use in the screening for dysplastic lesion.

CONCLUSION

Ileocolonoscopy allows an accurate diagnosis of Crohn's disease or ulcerative colitis in up to 90% of cases. The healing of the mucosa assessed by endoscopy after treatments despite not being consensus is still the gold-standard in the evaluation of remission of the disease. Colonoscopy is essential for long-term cancer surveillance and in the future the implementation of Confocal Laser Endomicroscopy seems to be very promising in assessing the initial dysplasia.

How Secure Is the Diagnosis of Ulcerative Colitis in Children, Even After Colectomy?

OBJECTIVES

We reviewed all children who have undergone a colectomy for ulcerative colitis (UC) in our tertiary referral centre in a 12-year period to assess the rate of reclassification as Crohn disease (CD). In contrast to CD, a colectomy is considered to be definitive treatment for patients with UC. Distinguishing between the 2 can be challenging when disease is manifest only within the colon-even histological examination of a colectomy specimen may be inconclusive. Historically, the recognised "rediagnosis" rate (post-colectomy) was reported at approximately 3% to 7%. A recent study suggested that a higher rate of 13% should be expected in children. This has implications in terms of pre-operative counselling and surgical decision making.

METHODS

A retrospective case-note review of all patients who underwent a colectomy for UC between 2003 and 2014 in a single paediatric tertiary referral centre was performed.

RESULTS

Of the 570 children diagnosed with inflammatory bowel disease in this period, 190 were diagnosed as UC. Of these 190 cases, 29 underwent a colectomy. None of these was re-classified following histological examination of the colectomy sample. Seven out of the 29 patients (24%) were subsequently diagnosed with CD (median follow-up 7.6 years). This is significantly higher than previously reported rates (P = 0.003).

CONCLUSIONS

Our data suggest that later manifestation of CD is more common than previously thought (24%). Therefore, a diagnosis of UC in children should be regarded as provisional and a potential later diagnosis of CD taken into account when considering colectomy and J-pouch formation.

Recent advances in clinical practice: a systematic review of isolated colonic Crohn's disease: the third IBD?

The genetics of isolated colonic Crohn's disease place it approximately midway between Crohn's disease with small intestinal involvement and UC, making a case for considering it as a separate condition. We have therefore systematically reviewed its epidemiology, pathophysiology and treatment. Key findings include a higher incidence in females (65%) and older average age at presentation than Crohn's disease at other sites, a mucosa-associated microbiota between that found in ileal Crohn's disease and UC, no response to mesalazine, but possibly better response to antitumour necrosis factor than Crohn's disease at other sites. Diagnostic distinction from UC is often difficult and also needs to exclude other conditions including ischaemic colitis, segmental colitis associated with diverticular disease and tuberculosis. Future studies, particularly clinical trials, but also historical cohorts, should assess isolated colonic Crohn's disease separately.

Clinical utility of double-balloon enteroscopy in suspected Crohn's disease: a single-centre experience

BACKGROUND

Small bowel Crohn's disease has a heterogeneous presentation leading to a delay in diagnosis. Capsule endoscopy is now a well-established diagnostic tool; however, few studies have evaluated the role of double-balloon enteroscopy (DBE) in patients with suspected Crohn's disease. Histology obtained at DBE is useful in addition to clinical symptoms, blood parameters and capsule endoscopy findings to aid diagnosis and further management.

OBJECTIVE

The aim of this study was to evaluate the impact of DBE and histology on the management of patients with suspected small bowel Crohn's disease.

METHODS

DBE procedures including histology for suspected Crohn's disease from 2006 to 2014 were retrospectively reviewed. Follow-up data for all patients were collected.

RESULTS

In our series of 399 double-balloon enteroscopies, 122 procedures were performed in 100 patients for suspected Crohn's disease. Positive DBE findings were found in 60% of patients. Forty-five per cent of patients were treated as Crohn's disease on the basis of a combination of histology, endoscopic appearance, clinical symptoms and blood parameters. Histology was diagnostic of Crohn's disease in 8% and supportive of it in 15%. In 12%, an alternative diagnosis was made, of whom two patients were diagnosed with small bowel malignancy on histology.After a median follow-up period of 27 months, the actual prevalence for a new diagnosis of Crohn's disease in our study was 38%.

CONCLUSION

DBE has a useful place in clarifying the diagnosis in patients with suspected Crohn's disease. Although histology can be nondiagnostic, the combination of the macroscopic appearance with clinical correlation is useful in the diagnosis and management.

Linkage between genotype and immunological phenotype in Crohn's disease

Understanding the mechanisms that drive uncontrolled inflammation in Crohn's disease (CD) remains one of the most pressing challenges in contemporary experimental medicine. Recently, a three-phased view on the pathogenesis of CD was proposed in which following the breakdown of intestinal epithelial barrier function, CD patients fail to clear the resulting infectious debris, provoking subsequent immune responses. This view on CD is attractive in that it is testable and allows better diagnosis of disease if proven correct, apart from opening a window on new therapeutic horizons. Here we shall argue, however, that this scheme may be an oversimplification in that it ignores the genetic diversity of CD and thus does not fully take into account the nature of the intestinal epithelium, which appears a non-passive actor in this disease.

Review article: the histological assessment of disease activity in ulcerative colitis

BACKGROUND

In patients with ulcerative colitis (UC), mucosal healing has emerged as a major therapeutic goal, and is usually assessed endoscopically. Histological healing does not correlate very well with endoscopic mucosal healing in UC and persistent histological inflammation might be a better predictor of future clinical relapse than the endoscopic appearance alone.

AIM

To define how histological assessment of disease activity should be best done in UC.

METHODS

Electronic (PubMed/Embase) and manual search.

RESULTS

At least 18 histological indices to assess disease activity in UC have been described, though none are fully validated. However, histological assessment is increasingly used as a secondary endpoint in clinical trials in UC. After reviewing and discussing existing histological scoring systems for UC activity, we describe features of histological response and define three grades of activity: (i) histological healing - complete resolution of abnormalities; (ii) quiescent disease, - lack of mucosal neutrophils but chronic inflammation may remain; (iii) active disease - presence of neutrophils plus possible epithelial damage. It is recommended that two biopsies are taken from each colonic segment which should include always biopsy of the rectum and the most affected segments. There is to date no agreed preferable scoring system but the Geboes Index is the best validated (kappa for interobserver variation 0.59-0.70).

CONCLUSION

Histological assessment of disease activity in UC is increasingly used, but needs to be carefully defined.

Quantitative assessment of CD30+ lymphocytes and eosinophils for the histopathological differential diagnosis of inflammatory bowel disease

BACKGROUND AND AIMS

The histopathological discrimination of Crohn's disease [CD] and ulcerative colitis [UC] can be challenging. The aim of this study was to evaluate if quantification of CD30(+) lymphocytes and eosinophils in histopathological material improves the accuracy of diagnosis of inflammatory bowel disease.

METHODS

A total of 156 patients were diagnosed with IBD by a gastroenterologist and corroborated by 5 years of follow-up. Patients were treatment naïve at the time of biopsy. Samples were taken from diseased areas of the colon and examined by a gastrointestinal pathologist.

RESULTS

The median number of eosinophils in biopsies from affected segments was 42/high power field [hpf] [25.5-63.5] in CD and 98/hpf [67-123] in UC [p < 0.001]. Biopsies containing ≥ 70 eosinophils/hpf field had a sensitivity of 78.3% and a specificity of 71% for the diagnosis of UC ({area under the receiver operating characteristic (ROC) curve 0.767 (95% confidence interval [CI] 0.696-0.838)}. There was a median of three CD30(+) cells/hpf [range 2-6] in diseased CD biopsies and 33 cells/hpf [24-52] in diseased UC biopsies [p < 0.001]. The cut-off determined by the ROC curve was 15 (sensitivity 97.4%, specificity 97.4%, positive likelihood ratio (PLR) 17.1, Negative likelihood ratio (NLR) 0.03, area under the curve [AUC]: 0.978; 95% CI 0.95310.999).

CONCLUSIONS

Routine histopathological assessment with quantification of CD30+ cells is highly accurate at discriminating CD and UC. All the measured parameters are easy to perform, low-cost, and available in most pathological laboratories.

Suppression of p21Rac signaling and increased innate immunity mediate remission in Crohn's disease

In inflammatory bowel disease (IBD), large areas of apparently healthy mucosa lie adjacent to ulcerated intestine. Knowledge of the mechanisms that maintain remission in an otherwise inflamed intestine could provide important clues to the pathogenesis of this disease and provide rationale for clinical treatment strategies. We used kinome profiling to generate comprehensive descriptions of signal transduction pathways in inflamed and noninflamed colonic mucosa in a cohort of IBD patients, and compared the results to non-IBD controls. We observed that p21Rac1 guanosine triphosphatase (GTPase) signaling was strongly suppressed in noninflamed colonic mucosa in IBD. This suppression was due to both reduced guanine nucleotide exchange factor activity and increased intrinsic GTPase activity. Pharmacological p21Rac1 inhibition correlated with clinical improvement in IBD, and mechanistically unrelated pharmacological p21Rac1 inhibitors increased innate immune functions such as phagocytosis, bacterial killing, and interleukin-8 production in healthy controls and patients. Thus, suppression of p21Rac activity assists innate immunity in bactericidal activity and may induce remission in IBD.

Transcriptional analysis of left-sided colitis, pancolitis, and ulcerative colitis-associated dysplasia

BACKGROUND

It is unknown why patients with extensive ulcerative colitis (UC) have a higher risk of colorectal cancer compared with patients with left-sided UC. This study characterizes the inflammatory processes in left-sided UC, pancolitis, and UC-associated dysplasia at the transcriptional level to identify potential biomarkers and transcripts of importance for the carcinogenic behavior of chronic inflammation.

METHODS

The Affymetrix GeneChip Human Genome U133 Plus 2.0 was applied on colonic biopsies from UC patients with left-sided UC, pancolitis, dysplasia, and controls. Reverse transcription polymerase chain reaction and immunohistochemistry were performed for validating selected transcripts in the initial cohort and in 2 independent cohorts of patients with UC. Microarray data were analyzed by principal component analysis, and reverse transcription polymerase chain reaction and immunohistochemistry data by the Wilcoxon's rank-sum test.

RESULTS

The principal component analysis results revealed separate clusters for left-sided UC, pancolitis, dysplasia, and controls. Close clustering of dysplastic and pancolitic samples indicated similarities in gene expression. Indeed, 101 and 656 parallel upregulated and downregulated transcripts, respectively, were identified in specimens from dysplasia and pancolitis. Validation of selected transcripts hereof identified insulin receptor alpha (INSRA) and MAP kinase interacting serine/threonine kinase 2 (MKNK2) with an enhanced expression in dysplasia compared with left-sided UC and controls, whereas laminin γ2 (LAMC2) was found with a lower expression in dysplasia compared with the remaining 3 groups.

CONCLUSIONS

This study demonstrates pancolitis and left-sided UC as distinct inflammatory processes at the transcriptional level, and identifies INSRA, MKNK2, and LAMC2 as potential critical transcripts in the inflammation-driven preneoplastic process of UC.

Immunopathological characterization of selected mouse models of inflammatory bowel disease: Comparison to human disease

Inflammatory bowel diseases (IBD) are chronic, relapsing conditions of multifactorial etiology. The two primary diseases of IBD are Crohn's disease (CD) and ulcerative colitis (UC). Both entities are hypothesized to occur in genetically susceptible individuals due to microbial alterations and environmental contributions. The exact etiopathogenesis, however, is not known for either disease. A variety of mouse models of CD and UC have been developed to investigate the pathogenesis of these diseases and evaluate treatment modalities. Broadly speaking, the mouse models can be divided into 4 categories: genetically engineered, immune manipulated, spontaneous and erosive/chemically induced. No one mouse model completely recapitulates the immunopathology of CD or UC, however each model possesses particular similarities to human IBD and offers advantageous for specific details of IBD pathogenesis. Here we discuss the more commonly used models in each category and critically evaluate how the immunopathology induced compares to CD or UC, as well as the advantages and disadvantages associated with each model.

The histopathological approach to inflammatory bowel disease: a practice guide

Inflammatory bowel diseases (IBDs) are lifelong disorders predominantly present in developed countries. In their pathogenesis, an interaction between genetic and environmental factors is involved. This practice guide, prepared on behalf of the European Society of Pathology and the European Crohn's and Colitis Organisation, intends to provide a thorough basis for the histological evaluation of resection specimens and biopsy samples from patients with ulcerative colitis or Crohn's disease. Histopathologically, these diseases are characterised by the extent and the distribution of mucosal architectural abnormality, the cellularity of the lamina propria and the cell types present, but these features frequently overlap. If a definitive diagnosis is not possible, the term indeterminate colitis is used for resection specimens and the term inflammatory bowel disease unclassified for biopsies. Activity of disease is reflected by neutrophil granulocyte infiltration and epithelial damage. The evolution of the histological features that are useful for diagnosis is time- and disease-activity dependent: early disease and long-standing disease show different microscopic aspects. Likewise, the histopathology of childhood-onset IBD is distinctly different from adult-onset IBD. In the differential diagnosis of severe colitis refractory to immunosuppressive therapy, reactivation of latent cytomegalovirus (CMV) infection should be considered and CMV should be tested for in all patients. Finally, patients with longstanding IBD have an increased risk for the development of adenocarcinoma. Dysplasia is the universally used marker of an increased cancer risk, but inter-observer agreement is poor for the categories low-grade dysplasia and indefinite for dysplasia. A diagnosis of dysplasia should not be made by a single pathologist but needs to be confirmed by a pathologist with expertise in gastrointestinal pathology.

Progress in histopathological diagnosis of ulcerative colitis

In recent years, the incidence of ulcerative colitis (UC) has been increasing year by year, which affect people's health and life seriously. Although UC is known as a clinical disease for more than a century, there is still a lack of specific diagnostic index for this disease. UC diagnosis is mainly based on clinical features, endoscopic findings and biopsy pathology as well as the exclusion of other diseases. Currently, histopathological diagnosis has become a research hot spot. Scholars around the world have attached great importance to the role of biopsy in the diagnosis of UC. This article will review recent progress in histopathological diagnosis of UC.

Ulcerative colitis or Crohn's disease? Pitfalls and problems

The interpretation of colorectal biopsies taken for the initial diagnosis of chronic idiopathic inflammatory bowel disease (IBD) is challenging. Subclassification of IBD as ulcerative colitis (UC) or Crohn's disease, which may be particularly difficult, is the subject of this review. Biopsies taken at first presentation are emphasised, partly because their features have not been modified by time or treatment. Aspects of longstanding disease and of resections are also mentioned. The first part of the review comprises background considerations and a summary of histological features that are discriminant, according to published evidence, between UC and Crohn's disease in initial biopsies. Pitfalls and problems associated with making the distinction between UC and Crohn's disease are then discussed. These include: mimics of IBD; inadequate clinical details; unreliable microscopic features; absence of histological changes in early IBD; discontinuity in UC; cryptolytic granulomas; differences between paediatric and adult UC; reliance on ileal and oesophagogastroduodenal histology; and atypical features in IBD resections. Avoidance by pathologists of known pitfalls should increase the likelihood of accurate and confident subclassification of IBD, which is important for optimum medical and surgical management.

European consensus on the histopathology of inflammatory bowel disease

The histologic examination of endoscopic biopsies or resection specimens remains a key step in the work-up of affected inflammatory bowel disease (IBD) patients and can be used for diagnosis and differential diagnosis, particularly in the differentiation of UC from CD and other non-IBD related colitides. The introduction of new treatment strategies in inflammatory bowel disease (IBD) interfering with the patients' immune system may result in mucosal healing, making the pathologists aware of the impact of treatment upon diagnostic features. The European Crohn's and Colitis Organisation (ECCO) and the European Society of Pathology (ESP) jointly elaborated a consensus to establish standards for histopathology diagnosis in IBD. The consensus endeavors to address: (i) procedures required for a proper diagnosis, (ii) features which can be used for the analysis of endoscopic biopsies, (iii) features which can be used for the analysis of surgical samples, (iv) criteria for diagnosis and differential diagnosis, and (v) special situations including those inherent to therapy. Questions that were addressed include: how many features should be present for a firm diagnosis? What is the role of histology in patient management, including search for dysplasia? Which features if any, can be used for assessment of disease activity? The statements and general recommendations of this consensus are based on the highest level of evidence available, but significant gaps remain in certain areas.

Inflammatory bowel disease biopsies: updated British Society of Gastroenterology reporting guidelines

Accurate histopathological assessment of biopsies is important for the diagnosis, subclassification, and management of chronic idiopathic inflammatory bowel disease (IBD). British Society of Gastroenterology (BSG) guidelines for the initial histopathological diagnosis of IBD were published in 1997. Changes since then include: more widespread use of full colonoscopy; greater recognition of the effects of time and treatment; improved documentation of variations in anatomical distribution; better understanding of the mimics of IBD; significant progress in clinical management; and modifications of terminology. Accordingly, an update is required. These revised guidelines aim to optimise the quality and consistency of reporting of biopsies taken for the initial diagnosis of IBD by summarising the literature and making recommendations based on the available evidence. Advice from existing clinical guidelines is also taken into account. Among the subjects discussed are: distinguishing IBD from other colitides, particularly infective colitis; subclassification of IBD (as ulcerative colitis, Crohn's disease, or IBD unclassified); the discriminant value of granulomas; aspects of disease distribution, including discontinuity in ulcerative colitis; time-related changes; differences between paediatric and adult IBD; the role of ileal and upper gastrointestinal biopsies; differential diagnoses such as diverticular colitis and diversion proctocolitis; and dysplasia. The need to correlate the histological features with clinical and endoscopic findings is emphasised. An approach to the conclusion of an IBD biopsy report based on the acronym Pattern, Activity, Interpretation, Dysplasia (PAID) is suggested. The key recommendations are listed at the end of the document.

Integration of transcriptomics and metabonomics: improving diagnostics, biomarker identification and phenotyping in ulcerative colitis

A systems biology approach to multi-faceted diseases has provided an opportunity to establish a holistic understanding of the processes at play. Thus, the current study merges transcriptomics and metabonomics data in order to improve diagnostics, biomarker identification and to explore the possibilities of a molecular phenotyping of ulcerative colitis (UC) patients. Biopsies were obtained from the descending colon of 43 UC patients (22 active UC and 21 quiescent UC) and 15 controls. Genome-wide gene expression analyses were performed using Affymetrix GeneChip Human Genome U133 Plus 2.0. Metabolic profiles were generated using 1H Nuclear magnetic resonance spectroscopy (Bruker 600 MHz, Bruker BioSpin, Rheinstetten, Germany). Data were analyzed with the use of orthogonal-projection to latent structure-discriminant analysis and a multivariate logistic regression model fitted by lasso. Prediction performance was evaluated using nested Monte Carlo cross-validation. The prediction performance of the merged data sets and that of relative small (<20 variables) multivariate biomarker panels suggest that it is possible to discriminate between active UC, quiescent UC, and controls; between patients with or without steroid dependency, as well as between early or late disease onset. Consequently, this study demonstrates that the novel approach of integrating metabonomics and transcriptomics combines the better of the two worlds, and provides us with clinical applicable candidate biomarker panels. These combined panels improve diagnostics and more importantly also the molecular phenotyping in UC and provide insight into the pathophysiological processes at play, making optimized and personalized medication a possibility.

A histopathologic scoring system as a tool for standardized reporting of chronic (ileo)colitis and independent risk assessment for inflammatory bowel disease

Pathologists regularly evaluate for the presence of chronic (ileo)colitis in lower gastrointestinal mucosal biopsies, for which a major differential diagnosis is inflammatory bowel disease. Although the histologic features of chronic (ileo)colitis are clearly defined, there is no standard, experimentally derived and validated terminology to document these findings in pathology reports and to convey the likelihood of inflammatory bowel disease in a compact, consistent style. This study had 2 retrospective and 1 prospective phases. In phase 1, we developed a histopathologic scoring system for chronic (ileo)colitis and measured the agreement in scoring between pathologists. In phase 2, we emulated the surgical pathology practice by scoring mucosal biopsies of 164 patients who had undergone lower gastrointestinal endoscopies for clinical suspicion of (ileo)colitis. The cases were matched to 6 different groups based on clinical diagnoses. In phase 3, we prospectively assessed accuracy and ease of application of the scoring system in our practice. The scoring system showed low interobserver variability (correlation coefficient, 0.94-0.96) and distinguished chronic (ileo)colitis from negative cases. In addition, it enabled us to provide probabilistic diagnostic statements based on total scores and their positive predictive values, conveying the likelihood of inflammatory bowel disease as low (<20%), intermediate (∼50%), and high (∼90%). In conclusion, this histopathologic scoring system might be a useful approach to report the findings of lower gastrointestinal mucosal biopsies and to provide measured opinion regarding chronic (ileo)colitis independent of available clinical information. In addition, a defined set of diagnostic statements with regard to likelihood of inflammatory bowel disease would reduce interpretive variability.

Can endoscopy be avoided in the assessment of ulcerative colitis in clinical trials?

BACKGROUND

There is no gold standard index in the measurement of ulcerative colitis (UC) disease activity in clinical trials. Mucosal healing has been described as an important clinical endpoint requiring endoscopic assessment, which is unpleasant for the patient and may hamper recruitment to trials. The aim of this study was to determine whether endoscopy is necessary in the assessment of UC disease activity and whether a noninvasive disease activity index (partial Mayo score) could be used to predict the Mayo score.

METHODS

In all, 149 subjects with moderate to severe UC enrolled in a clinical trial were assessed using total and partial Mayo scores. Histologic assessment of biopsies was performed. A regression model was constructed to predict total Mayo score from the partial Mayo score and histology score from the Mayo score. A Bland-Altman test of agreement was performed.

RESULTS

The partial Mayo score correlated closely with the total Mayo score at week 4 (rho = 0.97) and week 8 (rho = 0.98). The model to predict total from partial Mayo score showed excellent correlation (rho = 0.97) and good agreement with the total Mayo score at week 4 and the week 8 validation set (rho = 0.97) and accurately classified disease severity (kappa = 0.82). The model to predict histology score from the Mayo score correlated only moderately with the actual histology score at week 4 (rho = 0.59) and week 8 (rho = 0.36).

CONCLUSIONS

The Mayo score can be accurately predicted from the partial Mayo score. A noninvasive index can replace the Mayo score in future clinical trials.

Colorectal normal histology and histopathologic findings in patients with chronic diarrhea

Collagenous and lymphocytic colitis are common causes of chronic watery diarrhea that are characterized by distinct histopathologic abnormalities without endoscopically visible lesions and are summarized as microscopic colitis. Several variants of microscopic colitis have been described, although their clinical significance still has to be defined. Preserved mucosal architecture is a histologic hallmark of microscopic colitis and distinguishes the disease from inflammatory bowel disease (IBD). In addition to architectural abnormalities, the diagnosis of IBD rests on characteristic inflammatory changes. Differential diagnosis of IBD mainly includes prolonged infection and diverticular disease-associated colitis, also known as segmental colitis associated with diverticulosis.

Endoscopic assessment of inflammatory bowel disease: colonoscopy/esophagogastroduodenoscopy

Endoscopy plays an important role in the initial diagnosis of IBD, including the evaluation of disease severity, activity, and extent. The implications of complete mucosal healing further confirm the function of endoscopy in the follow-up of IBD patients. The use of therapeutic endoscopy, for example stricture dilatation, can avoid the need for bowel resection. Modalities such as capsule endoscopy, EUS, NBI, CE, and other emerging techniques are likely to have an increasing role in the management of IBD, particularly in the area of dysplasia surveillance and treatment.

Proteomic profiling of mucosal and submucosal colonic tissues yields protein signatures that differentiate the inflammatory colitides

BACKGROUND

Differentiating ulcerative colitis (UC) from Crohn's colitis (CC) can be difficult and may lead to inaccurate diagnoses in up to 30% of inflammatory bowel disease (IBD) patients. Much of the diagnostic uncertainty arises from the overlap of clinical and histologic features. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) permits a histology-directed cellular protein analysis of tissues. As a pilot study, we evaluated the ability of histology-directed MALDI-MS to determine the proteomic patterns for potential differences between CC and UC specimens.

METHODS

Mucosal and submucosal layers of CC and UC colon resection samples were analyzed after histologic assessment. To determine whether MALDI-MS would distinguish inflammation, the uninflamed (n = 21) versus inflamed submucosa (n = 22) were compared in UC and the uninflamed (n = 17) versus inflamed submucosa (n = 20) in CC. To determine whether there were proteomic differences between the colitides, the uninflamed UC submucosa (n = 21) was compared versus the uninflamed CC submucosa (n = 17), the inflamed UC submucosa (n = 22) was compared versus the inflamed CC submucosa (n = 20), and inflamed UC mucosa versus inflamed CC mucosa. Pairwise statistics comparisons of the subsets were performed.

RESULTS

Pairwise comparative analyses of the clinical groups allowed identifying subsets of features important for classification. Comparison of inflamed versus uninflamed CC submucosa showed two significant peaks: m/z 6445 (P = 0.0003) and 12692 (P = 0.003). In the case of inflamed versus uninflamed UC submucosa, several significant differentiating peaks were found, but classification was worse. Comparisons of the proteomic spectra of inflamed submucosa between UC and CC identified two discrete significant peaks: m/z 8773 (P = 0.006) and 9245 (P = 0.0009). Comparisons of the proteomic spectra of uninflamed submucosa between UC and CC identified three discrete significant peaks: m/z 2778 (P = 0.005), 9232 (P = 0.005), and 9519 (P = 0.005). No significantly different features were found between UC and CC inflamed mucosa.

CONCLUSIONS

MALDI-MS was able to distinguish CC and UC specimens while profiling the colonic submucosa. Further analyses and protein identification of the differential protein peaks may aid in accurately diagnosing IBD and developing appropriate personalized therapies.

Chronic idiopathic inflammatory bowel diseases: the histology report

The incidence of chronic idiopathic inflammatory bowel diseases (IBD) is growing in western countries, making their histological diagnosis an everyday task for all pathologists. Reviews from the literature strongly suggest that such diagnosis cannot be performed on the histological ground alone but requires a clinical-pathological approach. Moreover, bewildering variations can be observed in the terminology employed to report either individual lesions or diagnostic categories. The aim of the present paper is to suggest a practical diagnostic algorithm summarizing the main data from the literature. Particular emphasis has been placed on minimum clinical information required and the accurate definition of individual lesions. Diagnostic categories to employ and to avoid in daily practice have furthermore been stressed.

Diagnostic work-up of inflammatory bowel disease in children: the role of calprotectin assay

BACKGROUND

Some reports highlight the potential application of fecal calprotectin as a direct biomarker of intestinal inflammation and, therefore, as support in choosing candidates for endoscopy. The value of 100 μg/g was recently assumed as the best cutoff for this assay. The purpose of this study was to assess the diagnostic precision of the fecal calprotectin assay, compared to histology, as a stool-screening biomarker for inflammatory bowel disease (IBD) among a group of prospectively identified patients referred for recurrent abdominal pain and altered bowel habits.

METHODS

Between 1999 and 2007 we prospectively evaluated the calprotectin assay in a cohort of patients with recurrent abdominal pain and altered bowel habits associated or not with other symptoms suggestive of IBD. All patients suspected of IBD, according to Rome and Porto criteria, provided stool specimens for the calprotectin assay and subsequently underwent endoscopic procedures.

RESULTS

Compared to histology, the cutoff of 100 μg/g reached a sensitivity and specificity of 100% and 68%, respectively, and a likelihood ratio (LR) of 3.1. The cutoff value of 160 μg/g, however, in our series produced the best joint estimate of sensitivity and specificity: 100% and 80%, respectively, with an LR of 5.

CONCLUSIONS

In pediatric patients with recurrent abdominal pain and changes in stool habits, a positive calprotectin assay is closely associated with IBD; its systematic employment, therefore, seems to improve the process of endoscopy referral. This test, simple and inexpensive, could be included in the first noninvasive phase of an IBD diagnostic work-up.