Observer variability in the histologic diagnosis of microscopic colitis

Number of intraepithelial lymphocytes and presence of a subepithelial band in normal colonic mucosa differs according to stainings and evaluation method

Chronic watery diarrhea is a frequent symptom. In approximately 10% of the patients, a diagnosis of microscopic colitis (MC) is established. The diagnosis relies on specific, but sometimes subtle, histopathological findings. As the histology of normal intestinal mucosa vary, discriminating subtle features of MC from normal tissue can be challenging and therefore auxiliary stainings are increasingly used. The aim of this study was to determine the variance in number of intraepithelial lymphocytes (IELs) and presence of a subepithelial band in normal ileum and colonic mucosa, according to different stains and digital assessment. Sixty-one patients without diarrhea referred to screening colonoscopy due to a positive feacal blood test and presenting with endoscopically normal mucosa were included. Basic histological features, number of IELs, and thickness of a subepithelial band was manually evaluated and a deep learning-based algorithm was developed to digitally determine the number of IELs in each of the two compartments; surface epithelium and cryptal epithelium, and the density of lymphocytes in the lamina propria compartment. The number of IELs was significantly higher on CD3-stained slides compared with slides stained with Hematoxylin-and-Eosin (HE) (p<0.001), and even higher numbers were reached using digital analysis. No significant difference between right and left colon in IELs or density of CD3-positive lymphocytes in lamina propria was found. No subepithelial band was present in HE-stained slides while a thin band was visualized on special stains. Conclusively, in this cohort of prospectively collected ileum and colonic biopsies from asymptomatic patients, the range of IELs and detection of a subepithelial collagenous band varied depending on the stain and method used for assessment. As assessment of biopsies from patients with diarrhea constitute a considerable workload in the pathology departments digital image analysis is highly desired. Knowledge provided by the present study highlight important differences that should be considered before introducing this method in the clinic.

Autoimmune and immune-mediated inflammatory diseases after exposure to acid-suppressive medication: A systematic review and meta-analysis

BACKGROUND

Pharmacovigilance risk signals have proposed a relationship between the use of acid-suppressive medications and the development of certain autoimmune and immune-mediated inflammatory diseases.

OBJECTIVE

A systematic review and a meta-analysis was performed.

METHODS

We reviewed MEDLINE (Ovid) and Scopus for comparative observational studies between these diseases and previous exposure to proton-pump inhibitors (PPI), H2-receptor antagonists (H2RA), and antacids. The protocol was registered on the PROSPERO database (CRD42020192715).

RESULTS

From 3,191 citations, 25 articles were eligible and covered 16 diseases. Microscopic colitis (MC) was studied the most (7 studies). In a random-effects meta-analysis, there was low certainty evidence (GRADE approach) of a non-significant relationship between exposure to any PPIs and MC (meta-OR 3.28, 95% CI 0.98-11.0, I2 98.2%, six studies, 4,436 PPI-exposed MC patients). Moderate certainty evidence pointed towards large odds of collagenous colitis after exposure to lansoprazole (meta-OR 14.5, 95% CI 9.37-22.3, I2 10.2%, three studies, 1,725 lansoprazole-exposed patients). After PPI exposure, the risk of rheumatoid arthritis was slightly increased based on low certainty evidence from two cohort studies totaling 475 diagnoses (meta-RR 1.62, 95% CI 1.12-2.34, I2 34.5%).

CONCLUSIONS

In patients with MC, it would be reasonable to carefully review the indication of PPI, especially in CC patients using lansoprazole.

European guidelines on microscopic colitis: United European Gastroenterology and European Microscopic Colitis Group statements and recommendations

INTRODUCTION

Microscopic colitis is a chronic inflammatory bowel disease characterised by normal or almost normal endoscopic appearance of the colon, chronic watery, nonbloody diarrhoea and distinct histological abnormalities, which identify three histological subtypes, the collagenous colitis, the lymphocytic colitis and the incomplete microscopic colitis. With ongoing uncertainties and new developments in the clinical management of microscopic colitis, there is a need for evidence-based guidelines to improve the medical care of patients suffering from this disorder.

METHODS

Guidelines were developed by members from the European Microscopic Colitis Group and United European Gastroenterology in accordance with the Appraisal of Guidelines for Research and Evaluation II instrument. Following a systematic literature review, the Grading of Recommendations Assessment, Development and Evaluation methodology was used to assess the certainty of the evidence. Statements and recommendations were developed by working groups consisting of gastroenterologists, pathologists and basic scientists, and voted upon using the Delphi method.

RESULTS

These guidelines provide information on epidemiology and risk factors of microscopic colitis, as well as evidence-based statements and recommendations on diagnostic criteria and treatment options, including oral budesonide, bile acid binders, immunomodulators and biologics. Recommendations on the clinical management of microscopic colitis are provided based on evidence, expert opinion and best clinical practice.

CONCLUSION

These guidelines may support clinicians worldwide to improve the clinical management of patients with microscopic colitis.

Distribution of histopathological features along the colon in microscopic colitis

PURPOSE

The diagnosis microscopic colitis (MC) consisting of collagenous colitis (CC) and lymphocytic colitis (LC) relies on histological assessment of mucosal biopsies from the colon. The optimal biopsy strategy for reliable diagnosis of MC is controversial. The aim of this study was to evaluate the distribution of histopathological features of MC throughout the colon.

METHODS

Mucosal biopsies from multiple colonic segments of patients with MC who participated in one of the three prospective European multicenter trials were analyzed. Histological slides were stained with hematoxylin-and-eosin, a connective tissue stain, and CD3 in selected cases.

RESULTS

In total, 255 patients were included, 199 and 56 patients with CC and LC, respectively. Both groups exhibited a gradient with more pronounced inflammation in the lamina propria in the proximal colon compared with the distal colon. Similarly, the thickness of the subepithelial collagenous band in CC showed a gradient with higher values in the proximal colon. The mean number of intraepithelial lymphocytes was > 20 in all colonic segments in patients within both subgroups. Biopsies from 86 to 94% of individual segments were diagnostic, rectum excluded. Biopsies from non-diagnostic segments often showed features of another subgroup of MC.

CONCLUSION

Conclusively, although the severity of the histological changes in MC differed in the colonic mucosa, the minimum criteria required for the diagnosis were present in the random biopsies from the majority of segments. Thus, our findings show MC to be a pancolitis, rectum excluded, questioning previously proclaimed patchiness throughout the colon.

Microscopic colitis: pathophysiology and clinical management

Microscopic colitis is a chronic inflammatory disease of the colon that frequently causes chronic watery diarrhoea that might be accompanied by abdominal pain, nocturnal diarrhoea, urgency, and faecal incontinence. These symptoms lead to poor quality of life and increased health-care costs. Diagnosis relies on histological examination of multiple biopsy samples from the colonic mucosa, which often show no or only few abnormalities on endoscopy. Two major histological subtypes can be distinguished-collagenous colitis and lymphocytic colitis-but incomplete and variant forms with fewer characteristic features have been reported. Here we summarise the latest evidence on epidemiology, pathogenesis, and risk factors, and discuss established and novel therapeutic options for clinical remission. Finally, we propose an updated treatment algorithm. Further prospective studies are needed to clarify the natural history of microscopic colitis, supported by validated criteria for the assessment of disease activity.

An investigation of European pathologists' approach to diagnose microscopic colitis

Microscopic colitis (MC) comprising lymphocytic colitis (LC), collagenous colitis (CC) and the incomplete forms of microscopic colitis (MCi) are frequent causes of chronic watery diarrhea. The diagnosis is based on specific histological features in colonic biopsies. Especially regarding MCi, the histological features may be subtle. The PRO-MC collaboration was established in 2016 with the aims to systematically describe the disease course and to validate the diagnostic criteria of MC. In the present study, we analysed pathologists' initial approach to diagnose MC. Five pathologists with expertise in gastro-intestinal pathology reviewed the first 10 cases enrolled in the PRO-MC registry in six of the participating centres. Despite considerable differences in strategies in biopsy sampling, in choice of stains and in minimum number of biopsies and segments required for diagnosing MC, inter-observer agreement between the participating centres and expert pathologists as well as among the latter was substantial. Disagreed cases most often related to difficulties in distinguishing between MC subgroups. We recommend that pathologists as well as clinicians reach consensus in their diagnostic approach to MC, which is a prerequisite to compare MC cohorts internationally and to facilitate clinical MC trials and follow-up studies.

Effects of subspecialty signout and group consensus on the diagnosis of microscopic colitis

Microscopic colitis (MC) includes lymphocytic colitis (LC) and collagenous colitis (CC). Microscopic changes are required to establish these diagnoses. While criteria exist, interobserver variability has been reported previously. This has not been evaluated in the context of subspecialty signout (SSSO) or a consensus conference. We identified 133 colon biopsies diagnosed as LC, CC, MC, or normal but with mild changes insufficient for MC. All predated the introduction of SSSO at our institution. They were independently reviewed by three gastrointestinal (GI) pathologists. Cases lacking independent consensus were reviewed by the same pathologists in consensus conference to establish a final diagnosis. Individual diagnoses were compared with the consensus diagnoses, and consensus diagnoses were compared with original diagnoses made by GI and non-GI pathologists. Consensus diagnoses were normal (n = 34), LC (n = 57), and CC (n = 42). "Normal" was the diagnosis most commonly agreed upon independently (27/34 cases, P = 0.0073 versus LC, P = 0.0172 versus CC). The reviewing pathologists independently agreed with 80%, 80%, and 94% of consensus diagnoses (κ = 0.70, 0.69, and 0.91). The group consensus agreed with the diagnoses in 49 of 58 (84%) cases originally signed out by non-GI pathologists (κ = 0.77) and in 44 of 57 (77%) cases originally signed out by GI pathologists (κ = 0.63). Good interobserver agreement exists for MC, though whether GI subspecialty training improves agreement remains unclear. Group consensus may aid in diagnosis of difficult/borderline MC cases.

Intraobserver and Interobserver Variability in the Assessment of Dysplasia in Ampullary Mucosal Biopsies

Endoscopic mucosal biopsies of the ampulla of Vater (AmpBx) are obtained to histologically assess for dysplasia or carcinoma. However, biopsy material is often scant and a host of factors can induce histologic changes that pose diagnostic challenges. We sought to investigate observer variability in interpretation of AmpBx and the impact clinical data may have on diagnostic interpretation. Thirty-one cases from institutional archives were selected, including 12 cases of reactive atypia (RA), 8 indefinite for dysplasia (ID), and 11 showing low-grade dysplasia (LGD). Slides were independently reviewed at 3 time points with and without clinical information by 6 pathologists who categorized the biopsies RA, ID, or LGD. Following the reviews, intraobserver and interobserver agreement was assessed. Review of AmpBx without clinical data showed fair (κ, 0.27), poor (κ, 0.07), and good (κ, 0.42) interobserver agreement for diagnoses of RA, ID, and LGD, respectively. Interobserver agreement improved for LGD (κ, 0.66 and 0.73) when clinical information was provided; however, agreement remained fair for RA (κ, 0.4 and 0.42) and poor-to-fair for ID (κ, 0.17 and 0.25). When follow-up data were reviewed, all cases that reached unanimous agreement had that diagnosis substantiated by subsequent endoscopic or histologic findings. The same was true of 13 of 19 cases that reached majority consensus. Given the potential clinical consequences of these diagnoses combined with the significant intraobserver and interobserver variability found in this study, we conclude that better-defined diagnostic criteria and consensus reads on difficult cases would assist in the histologic assessment of these challenging cases.

Prevalence, Pathogenesis, Diagnosis, and Management of Microscopic Colitis

Microscopic colitis (MC), which is comprised of lymphocytic colitis and collagenous colitis, is a clinicopathological diagnosis that is commonly encountered in clinical practice during the evaluation and management of chronic diarrhea. With an incidence approaching the incidence of inflammatory bowel disease, physician awareness is necessary, as diagnostic delays result in a poor quality of life and increased health care costs. The physician faces multiple challenges in the diagnosis and management of MC, as these patients frequently relapse after successful treatment. This review article outlines the risk factors associated with MC, the clinical presentation, diagnosis and histologic findings, as well as a proposed treatment algorithm. Prospective studies are required to better understand the natural history and to develop validated histologic endpoints that may be used as end points in future clinical trials and serve to guide patient management.

Fatigue and its associated factors in microscopic colitis

BACKGROUND

Fatigue is a well-recognized symptom in patients with inflammatory bowel disease and irritable bowel syndrome (IBS), and has been associated with psychological comorbidity and impaired quality of life in both. However, features associated with fatigue in patients with microscopic colitis (MC) are less clear.

MATERIALS AND METHODS

We conducted a cross-sectional survey of patients with a new diagnosis of MC including levels of anxiety, depression, somatization, quality of life, and IBS-type symptoms. Levels and impact of fatigue were assessed using the Inflammatory Bowel Disease Fatigue self-assessment scale. Mean scores were compared against various patient characteristics, and were also correlated with anxiety, depression, somatization, and quality-of-life scores.

RESULTS

In total, 129 patients with MC diagnosed between 2010 and 2015 returned completed postal questionnaires. Common histological subtypes were collagenous colitis (53.5%, n = 69) and lymphocytic colitis (38.8%, n = 50). Higher mean fatigue severity and impact scores were associated with the presence of irritable-bowel-syndrome-type symptoms, abnormal levels of anxiety and depression, and high levels of somatization (p < 0.0001 for all), but those reporting ongoing symptoms attributable to MC did not report significantly higher scores. There were significant positive correlations between total anxiety, depression, or somatization scores and fatigue severity and impact scores, and significant negative correlations with quality-of-life measures (p < 0.001 for all).

CONCLUSIONS

Fatigue in MC appears to be associated with reporting IBS-type symptoms, psychological comorbidity and impaired quality of life. It may therefore represent an important target for treatment.

Significant association between the use of different proton pump inhibitors and microscopic colitis: a nationwide Danish case-control study

BACKGROUND

Microscopic colitis causes chronic watery diarrhoea and has previously been associated with the use of proton pump inhibitors.

AIM

To explore the association between proton pump inhibitor use and microscopic colitis, including its dependency on timing, dose and choice of proton pump inhibitor.

METHODS

Within a 10-year period, we identified 10 652 patients with a first-time diagnosis of microscopic colitis, including 6254 (59%) with collagenous colitis and 4398 (41%) with lymphocytic colitis. All microscopic colitis cases were histologically confirmed in the Danish Pathology Register. Information on proton pump inhibitor use was obtained from the Danish Prescription Register. In this case-control study, we estimated the adjusted odds ratios (aOR) for the association between proton pump inhibitor use and risk of microscopic colitis using conditional logistic regression while adjusting for potential confounders.

RESULTS

We found strong associations between current proton pump inhibitor use and both collagenous colitis (aOR 6.98; 95% CI: 6.45-7.55) and lymphocytic colitis (aOR 3.95; 95% CI: 3.60-4.33). This association was observed with all PPIs. The strongest association was with the current use of lansoprazole for both collagenous colitis (aOR 15.74; 95% CI: 14.12-17.55) and lymphocytic colitis (aOR 6.87; 95% CI: 6.00-7.86). When considering timing, ORs were highest for current use of proton pump inhibitor and lower for recent or past exposure. No clear dose-response pattern was observed.

CONCLUSIONS

We found a strong association between microscopic colitis and ongoing use of proton pump inhibitors, especially lansoprazole.

High prevalence of irritable bowel syndrome-type symptoms in microscopic colitis: implications for treatment

BACKGROUND

Patients with microscopic colitis (MC) often present with abdominal pain and diarrhoea, and previous data suggest that there may be overlap between MC and irritable bowel syndrome (IBS). We evaluated the prevalence of IBS-type symptoms in patients with MC, and assess the impact of these symptoms on psychological health and quality of life.

METHODS

We conducted a cross-sectional survey of individuals with a histological diagnosis of MC, collecting demographic data, Rome III IBS-type symptoms, and mood, somatization, and quality of life data.

RESULTS

In total, 151 (31.6%) of 478 individuals with a new diagnosis of MC completed questionnaires, 52 (34.4%) of whom reported IBS-type symptoms. The commonest histological subtype was collagenous colitis (51.7%, n = 78), followed by lymphocytic colitis (39.1%, n = 59). Individuals with IBS-type symptoms had significantly higher levels of anxiety [Hospital Anxiety and Depression Scale (HADS) anxiety score 8.6 versus 5.1, p < 0.001], depression (HADS depression score 6.2 versus 3.6, p = 0.001), and somatoform-type behaviour (Patient Health Questionnaire 15 score 12.7 versus 8.0, p < 0.001) compared with individuals who did not. Those with IBS-type symptoms scored significantly worse across all domains of the 36-item Short Form questionnaire, except for physical functioning.

CONCLUSIONS

More than one third of individuals with MC reported IBS-type symptoms, although whether this is due to ongoing inflammation is unclear. These individuals had higher levels of anxiety, depression, and somatization, and impaired quality of life. Identifying concomitant IBS in individuals with MC may have important implications for management decisions.

The subtypes of microscopic colitis from a pathologist's perspective: past, present and future

Microscopic colitis (MC) is a chronic inflammatory bowel disease, encompassing a triad of chronic diarrhea, normal endoscopy and characteristic histological findings. MC embraces two histological subtypes described as lymphocytic colitis (LC) and collagenous colitis (CC). The diagnostic criteria of MC were established several years ago and the histological description of LC and CC was based almost exclusively on heamatoxylin-eosin (HE) stained sections. Since the establishment of the diagnostic criteria, important changes have occurred in the concept and diagnostic methods of MC: the emergence of the entity "microscopic colitis incomplete" (MCi), comprising collagenous colitis incomplete (CCi) and lymphocytic colitis incomplete (LCi) and pathologists' increasing use of special stains in everyday diagnostics. The diagnostic challenges of today are threefold: which stains to apply to properly distinguish between MC, MCi and slight inflammatory changes, how to handle cases of diagnostic uncertainty and how to minimize inter observer variability. The views of this article are from the pathologist's perspective. We describe the changes in criteria and diagnostic methods of MC occurring over time, discus pathologists' diagnostic challenges and suggest how these can be met: by automated image analysis of tissue sections and by international collaboration under auspices of the PRO-MC collaboration, a European collaboration on the disease course of MC.

Macroscopic findings, incidence and characteristics of microscopic colitis in a large cohort of patients from the United Kingdom

OBJECTIVE

Microscopic colitis (MC) is classically associated with normal or near-normal endoscopic appearances. However, non-specific macroscopic findings have been described, the importance of biopsy location for confirming a diagnosis of MC is unclear, and reported incidence data from the United Kingdom are limited. This study was designed to assess macroscopic features, incidence, demographics, and location and positivity of biopsy samples in MC.

MATERIALS AND METHODS

Retrospective, cross-sectional study of individuals with newly diagnosed MC.

RESULTS

From 2010 to 2015, 540 cases of MC were reported. Macroscopic findings occurred in 16.5% (n = 89) cases, with trends towards increased frequency of ulceration or linear scarring in collagenous colitis (CC). The mean incidence of MC was 11.3 per 100,000 population/year, including 291 (53.9%) with CC (incidence 6.1 per 100,000/year), 203 (37.6%) with lymphocytic colitis (incidence 4.2 per 100,000/year) and 46 (8.5%) with MC, not otherwise specified. Most individuals were female (70.2%). Common features in patients with MC included symptom duration <6 months, weight loss, abdominal pain and use of proton pump inhibitors, statins, or non-steroidal anti-inflammatory drugs. In individuals with right- and left-sided biopsies taken, 98.2% had diagnostic features in both. However, rectal biopsies were only positive in 88.7%.

CONCLUSIONS

One in six patients with MC demonstrated distinct macroscopic findings at colonoscopy. Our data confirm a female preponderance in MC, a relatively short symptom duration and use of certain drugs as common features. Both right- and left-sided biopsies were frequently positive, suggesting flexible sigmoidoscopy and biopsy could confirm a diagnosis in certain individuals.

Over 90% of cases of Microscopic Colitis can be diagnosed by performing a short colonoscopy

AIMS

To determinate the topographical distribution of key diagnostic histological features of lymphocytic colitis (LC) and collagenous colitis (CC) and to establish what correlations may exist between the histological findings and the causes and severity of MC.

PATIENTS AND METHODS

Patients with MC were included in a prospective multicentre French study from September 2010 to October 2012. MC was diagnosed by performing total colonoscopy with multiple biopsies of the rectum and colon collected in separate jars and analyzed separately for each site (descending and sigmoid colon, transverse colon, ascending colon). CC was defined as a subepithelial collagen layer>10μm thick and LC as an intraepithelial lymphocyte (IEL) count>20 lymphocytes per 100 epithelial cells without any associated thickening of the subepithelial collagen.

RESULTS

Ninety-five patients, 69 with LC 26 and with CC, were included in the analysis. The sensitivity of the biopsies for diagnosing MC was maximum in the transverse colon and minimum in the rectum. Rectal and left colonic biopsies resulted in the diagnosis of CC and CL in 93% and 94% of cases, respectively. All the remaining cases of MC were diagnosed by performing additional biopsies beyond the splenic flexure. In patients with LC, a higher rate of IELs was associated with the absence of abdominal pain (P=0.01) and a shorter duration of diarrhea (P=0.001). In patients with CC, a lower level of collagen thickness in the basement membrane was associated with the presence of an autoimmune disease (P=0.02).

CONCLUSION

More than 90% of cases of microscopic colitis were diagnosed in this study by performing rectal and left colonic biopsies.

Incidence, Clinical Presentation, and Associated Factors of Microscopic Colitis in Northern France: A Population-Based Study

OBJECTIVE

To date, there are no epidemiological data on microscopic colitis (MC) in France. The aim of this study was to determine the incidence of MC in the Somme department in Northern France, to evaluate clinical characteristics, and to search for risk factors for both collagenous colitis (CC) and lymphocytic colitis (LC).

DESIGN

Between January 1, 2005, and December 31, 2007, four pathology units in the Somme department recorded all new cases of MC diagnosed in patients living in the area. Colonic biopsies were reviewed by 4 pathologists together. For each incident case, demographic, clinical, endoscopic, and biological data were collected according to methodology of the EPIMAD registry.

RESULTS

One hundred and thirty cases of MC, including 87 CC and 43 LC, were recorded during the three-year study. The mean annual incidence for MC was 7.9/10⁵ inhabitants, 5.3/10⁵ inhabitants for CC, and 2.6/10⁵ inhabitants for LC. Annual standardized incidence of Crohn's disease and ulcerative colitis in the EPIMAD registry during the same period (2005-2007) were 7.4/10⁵ and 4.9/10⁵, respectively. Median age at diagnosis was 63 years for MC, 70 for CC, and 48 for LC. The female-to-male gender ratio was 3.5 for MC, 4.1 for CC, and 2.6 for LC. Median time to diagnosis was 8 weeks. Chronic diarrhea and abdominal pain were, respectively, present in 93 and 47 % of the cases. An autoimmune disease was associated in 28 % of MC cases. At diagnosis, proton pump inhibitor treatment was more often reported in CC than in LC (46 vs 16 %; p = 0.003). Budesonide was effective on diarrhea in 77 % of patients, and thirteen percent of patients became steroid dependent.

CONCLUSION

This population-based study shows that the incidence of MC in France is high and similar to Crohn's disease incidence and confirms that this condition is associated with female gender, autoimmune diseases, and medications.

Towards a new paradigm of microscopic colitis: Incomplete and variant forms

Microscopic colitis (MC) is a chronic inflammatory bowel disease that has emerged in the last three decades as a leading cause of chronic watery diarrhoea. MC classically includes two main subtypes: lymphocytic colitis (LC) and collagenous colitis (CC). Other types of histopathological changes in the colonic mucosa have been described in patients with chronic diarrhoea, without fulfilling the conventional histopathological criteria for MC diagnosis. Whereas those unclassified alterations remained orphan for a long time, the use of the term incomplete MC (MCi) is nowadays universally accepted. However, it is still unresolved whether CC, LC and MCi should be considered as one clinical entity or if they represent three related conditions. In contrast to classical MC, the real epidemiological impact of MCi remains unknown, because only few epidemiological studies and case reports have been described. MCi presents clinical characteristics indistinguishable from complete MC with a good response to budesonide and cholestiramine. Although a number of medical treatments have been assayed in MC patients, currently, there is no causal treatment approach for MC and MCi, and only empirical strategies have been performed. Further studies are needed in order to identify their etiopathogenic mechanisms, and to better classify and treat MC.

Validation and modification of a diagnostic scoring system to predict microscopic colitis

OBJECTIVE

Many patients with diarrhoea undergo colonoscopy. If this is macroscopically normal, random biopsies are obtained to rule out microscopic colitis (MC), but most patients have functional disease. Accurate predictors of MC could avoid the need to take biopsies in a substantial proportion of patients, saving money for the health service. We validated a previously described diagnostic scoring system for MC, and incorporated further variables to assess whether this improved performance.

MATERIAL AND METHODS

Consecutive adults with loose stools undergoing colonoscopy in Leeds, UK were included. Demographic and symptom data were collected prospectively. The diagnostic scoring system described previously was applied. In addition, the incorporation of further variables, including drugs associated with MC, number of stools, nocturnal passage of stools, and duration of loose stools, into the scoring system was assessed. Sensitivities, specificities, and positive and negative predictive values were calculated.

RESULTS

Among 242 patients (mean age 51.0 years, 163 (67.4%) female), 26 (10.7%) of whom had MC, a cut off of ≥4 on the original scoring system had a sensitivity of 92.3% and specificity of 35.2%. Nocturnal passage of stools and duration of loose stools <6 months were significant predictors of MC. Incorporating these variables in a new scoring system with a cut off of ≥6 identified MC with 95.7% sensitivity and 46.0% specificity.

CONCLUSIONS

Incorporating nocturnal passage of stools and duration of loose stools into the scoring system may improve ability to predict MC, and avoid random colonic biopsies in a greater proportion of patients with loose stools.

Advances for improved diagnosis of microscopic colitis in patients with chronic diarrhoea

Microscopic colitis is a generic term that includes 2 main forms, collagenous colitis and lymphocytic colitis, and describes a form of inflammatory bowel disease with a chronic and relapsing course. The incidence of microscopic colitis is between 2 and 8 times higher in women than in men, although age, more than sex, increases the risk of collagenous colitis (odds ratio [OR] 8.3 for age ≥65 vs. <65 and OR 2.8 for women). The main symptom is chronic non-bloody watery diarrhoea. Other common symptoms include abdominal pain (50%-70%), with the result that many patients with microscopic colitis meet criteria for irritable bowel syndrome. Colonoscopy with multiple colonic biopsies is currently recommended, as histological changes are the main characteristic feature. The colonic mucosa is macroscopically normal, although certain minimal endoscopic abnormalities have been described.

The Temporal Evolution of Histological Abnormalities in Microscopic Colitis

BACKGROUND AND AIMS

Microscopic colitis (MC) is a common cause of chronic watery diarrhoea but long-term follow-up data are sparse.

METHODS

We performed a retrospective review of health records and all pathology reports in a regional cohort of patients with MC to describe the change in pre- and post-diagnostic colon biopsies.

RESULTS

MC was diagnosed in 468 patients with collagenous colitis (CC), 361 with lymphocytic colitis (LC) and 226 with incomplete MC (MCi). The 2014 incidence of CC, LC and MCi was 14.5, 14.9 and 5 per 10(5). Biopsies from both right and left colon were obtained in 237 (51%) patients with CC, 200 (55%) with LC and 107 (47%) with MCi. The diagnostic sensitivities of both left- and right-sided biopsies for MC were high and did not differ. Pre-diagnostic biopsies were obtained in 150 patients and lamina propria inflammation was described in 59, 47 and 43% of patients with a diagnosis of CC, LC and MCi respectively within 1 year, while histology was normal in 16, 13 and 21%. Post-diagnostic biopsies were obtained in 283 patients. MC persisted for up to one year in 77% with CC, 64% with LC and 45% with MCi, of whom 6, 9 and 18% respectively changed to a different MC subgroup.

CONCLUSIONS

Colonic biopsies obtained prior to the MC diagnosis often revealed increased lamina propria inflammation. The pathological changes of CC and LC are more persistent than those of MCi. Biopsies from the descending or sigmoid colon are sufficient to elucidate whether a patient with chronic watery diarrhoea has MC.

Current concepts on microscopic colitis: evidence-based statements and recommendations of the Spanish Microscopic Colitis Group

BACKGROUND

Microscopic colitis (MC) is an underdiagnosed inflammatory bowel disease.

AIM

To develop an evidence-based clinical practice guide on MC current concepts.

METHODS

Literature search was done on the Cochrane Library, EMBASE and MEDLINE electronic databases, which were consulted covering the period up until March 2015. Work groups were selected for each of the reviewed topics, with the purpose of drafting the initial statements and recommendations. They subsequently underwent a voting process based on the Delphi method. Each statement/recommendation was accompanied by the result of the vote the level of evidence, and discussion of the corresponding evidence. The grade of recommendation (GR) using the GRADE approach was established for diagnosis and treatment recommendations.

RESULTS

Some key statements and recommendations are: advancing age increases the risk of developing MC, mainly in females. The symptoms of MC and IBS-D may be similar. If MC is suspected, colonoscopy taking biopsies is mandatory. Treatment with oral budesonide is recommended to induce clinical remission in patients with MC. Oral mesalazine is not recommended in patients with collagenous colitis for the induction of clinical remission. The use of anti-TNF-alpha drugs (infliximab, adalimumab) is recommended for the induction of remission in severe cases of MC that fail to respond to corticosteroids or immunomodulators, as an alternative to colectomy.

CONCLUSIONS

This is the first consensus paper on MC based on GRADE methodology. This initiative may help physicians involved in care of these patients in taking decisions based on evidence.

CD3 immunohistochemical staining in diagnosis of lymphocytic colitis

Microscopic colitis (MC) is a common cause of chronic watery diarrhea. Traditionally, MC encompasses the 2 subgroups lymphocytic colitis (LC) and collagenous colitis, but recently, an additional subgroup, MC incomplete, has been introduced. Distinguishing between the subgroups relies exclusively on histopathologic evaluation. In the present study, 4 pathologists evaluated 156 archived biopsies originally diagnosed as LC or LC incomplete (LCi). Each pathologist assigned a diagnosis of LC, LCi, or nonspecific inflammation to all cases at 2 independent assessments. At the first assessment, hematoxylin and eosin (HE) stainings were available. At the second assessment, a supplementary CD3 immunohistochemical staining was also available. The aim was to evaluate whether a supplementary CD3 would increase the diagnostic agreement among pathologists, and whether a CD3 stain would change the diagnosis based on HE staining only. After the complete assessment, the cases were divided into 3 groups, that is, full agreement, partial agreement, and disagreement. The CD3 staining increased the number of cases with full agreement from 60 to 78. One hundred thirty-one cases with agreement or partial diagnostic agreement based on HE + CD3 were compared with the HE diagnoses. In 44 (34%) of 131 cases, CD3 changed the diagnosis. Cases assigned to the LCi category based on HE were often changed by a supplementary CD3. Conclusively, it is recommended to use a CD3 before giving the histopathologic diagnosis of LCi.

Automated image analysis in the study of collagenous colitis

PURPOSE

The aim of this study was to develop an automated image analysis software to measure the thickness of the subepithelial collagenous band in colon biopsies with collagenous colitis (CC) and incomplete CC (CCi). The software measures the thickness of the collagenous band on microscopic slides stained with Van Gieson (VG).

PATIENTS AND METHODS

A training set consisting of ten biopsies diagnosed as CC, CCi, and normal colon mucosa was used to develop the automated image analysis (VG app) to match the assessment by a pathologist. The study set consisted of biopsies from 75 patients. Twenty-five cases were primarily diagnosed as CC, 25 as CCi, and 25 as normal or near-normal colonic mucosa. Four pathologists individually reassessed the biopsies and categorized all into one of the abovementioned three categories. The result of the VG app was correlated with the diagnosis provided by the four pathologists.

RESULTS

The interobserver agreement for each pair of pathologists ranged from κ-values of 0.56-0.81, while the κ-value for the VG app vs each of the pathologists varied from 0.63 to 0.79. The overall agreement between the four pathologists was κ=0.69, while the overall agreement between the four pathologists and the VG app was κ=0.71.

CONCLUSION

In conclusion, the Visiopharm VG app is able to measure the thickness of a sub-epithelial collagenous band in colon biopsies with an accuracy comparable to the performance of a pathologist and thereby provides a promising supplementary tool for the diagnosis of CC and CCi and in particular for research.

Development and validation of a scoring system to identify patients with microscopic colitis

BACKGROUND & AIMS

Diarrhea is a common indication for colonoscopy. Biopsies are collected and analyzed from patients with a macroscopically normal colon to exclude microscopic colitis (MC), but the diagnostic yield is low because most patients have functional disease. We developed and validated a diagnostic scoring system to identify patients with MC to reduce the need to collect biopsies from all patients.

METHODS

We performed a retrospective study, which analyzed demographic and symptom data from adult patients with chronic diarrhea evaluated by colonoscopy and biopsy at 3 endoscopy centers in Leeds, United Kingdom. To derive the scoring system, we analyzed data from 476 adult patients (mean age, 53.6 years; 63.7% female) examined in 2011. Factors significantly associated with the presence of MC were assigned item scores, and total scores were determined for each patient. To validate the system, we used it to assess data from 460 patients (mean age, 52.9 years; 59.8% female) examined in 2012. The primary aim of the study was to determine the performance of the diagnostic scoring system in identifying patients with MC by using histologic findings as a reference.

RESULTS

In the derivation cohort, 85 patients were diagnosed with MC on the basis of histologic analysis. Age ≥50 years, female sex, use of proton pump inhibitors or nonsteroidal anti-inflammatory drugs, weight loss, and absence of abdominal pain were significantly associated with MC. We created a scoring system for diagnosis of MC, with scores ranging from -8 to +38; scores ≥8 were used to identify the presence of MC. This cutoff value identified patients with MC in the validation cohort (74 patients, 16.1%) with 90.5% sensitivity and 45.3% specificity (area under the receiver operating characteristic curve value, 0.76). Because of its ability to exclude MC and therefore avoid the need for routine collection of colonic biopsies, this scoring system reduced the cost of evaluation by >£7000 in the cohort.

CONCLUSIONS

We collected data on risk factors for MC to create a scoring system that identifies patients with MC with more than 90% sensitivity. This system can also reduce costs by identifying patients who are unlikely to have MC who do not require biopsy analysis.

The epidemiology of microscopic colitis: a 10-year pathology-based nationwide Danish cohort study

OBJECTIVE

Microscopic colitis (MC) includes two main types: collagenous colitis (CC) and lymphocytic colitis (LC). Previous studies have indicated an increasing incidence, but these have mainly been based on regional databases. We found it important to study the epidemiology based on a comprehensive nationwide cohort.

MATERIAL AND METHODS

We studied the epidemiological data of MC in Denmark from 2002 to 2011. The cohort consisted of all patients with a recorded diagnosis of either CC or LC in the Danish Pathology Register during the study period. Data on all patients with a registered colon biopsy were also included.

RESULTS

A total of 7777 patients, 4749 (61%) with CC and 3028 (39%) with LC, were identified. Over the study period, the annual incidence of diagnosed cases of CC increased from 2.9/10(5) to 14.9/10(5) and of LC from 1.7/10(5) to 9.8/10(5). In 2011, the incidence of MC was 24.7/10(5) inhabitants. The age-specific incidence showed that the risk of both CC and LC increased with age. The female/male ratio, distribution of the type of colitis and mean age at diagnosis were relatively stable during the study period. The annual number of registered colon biopsies in the pathology register increased from 21.583 in 2002 to 39.733 in 2011, indicating an increased diagnostic activity.

CONCLUSION

In a nationwide cohort study, the incidence of CC and LC continued to increase from 2002 to 2011. An increased diagnostic activity could in part explain the increase in the number of diagnosed cases.

Histology of microscopic colitis-review with a practical approach for pathologists

Microscopic colitis has emerged as a major cause of chronic watery non-bloody diarrhoea, particularly in elderly females. The term is used as an umbrella term to categorize a subgroup of colitides with distinct clinicopathological phenotypes and no significant endoscopic abnormalities. Lymphocytic colitis is defined by an increased number of surface intraepithelial lymphocytes, and collagenous colitis by a thickened collagen band underneath the surface epithelium. There is increased inflammation in the lamina propria, but only little or no crypt architectural distortion. Incomplete and variant forms showing less characteristic features have been reported under different names. The differential diagnosis mainly includes resolving infectious colitis and changes related to the intake of drugs such as non-steroidal anti-inflammatory drugs. Substantial clinical and histological overlap between lymphocytic and collagenous colitis has been described, raising the suspicion that the conditions are two histological manifestations of the same entity, possibly representing different manifestations during the disease course or different stages of disease development. In this review, we provide a practical approach for pathologists, with a focus on diagnostic criteria and differential diagnosis, and discuss recent insights into the pathogenesis of disease and the relationship with classic chronic inflammatory bowel disease, i.e. Crohn's disease and ulcerative colitis.

Drug exposure and risk of microscopic colitis: a nationwide Danish case-control study with 5751 cases

BACKGROUND

Previous small studies have indicated that commonly prescribed drugs may be associated with microscopic colitis (MC). With an increasing incidence of MC, it is important to explore the association between exposure to proton pump inhibitors (PPIs), nonsteroidal anti-inflammatory drugs, statins, and selective serotonin reuptake inhibitors and MC in a larger setting.

METHODS

Case-control study based on nationwide Danish registries. The study included all patients with MC diagnosis during the period 2005 to 2011. One hundred sex- and age-matched controls per case were randomly selected among the Danish population. Prescriptions were recorded in a Prescription Register in the year before the first recorded MC diagnosis. Effect measure is the adjusted odds ratio (OR) of collagenous colitis (CC) and lymphocytic colitis (LC) according to prescriptions of PPIs, nonsteroidal anti-inflammatory drugs, statins, and selective serotonin reuptake inhibitors. Within the control group, we identified a subgroup with MC-free colonic biopsies.

RESULTS

We identified 3474 patients with CC and 2277 with LC and found a positive association between redemption of prescriptions for PPIs and both CC (OR = 7.04; 95% confidence interval, 6.55-7.56) and LC (OR = 3.37; 95% confidence interval, 3.08-3.69). Among patients with MC-free colon biopsies in the control group, the association between PPIs and CC was strongly positive (OR = 3.47; 95% confidence interval, 3.08-3.89). Adding this parameter to the model attenuated all of the associations, but they remained positive for PPIs versus CC and selective serotonin reuptake inhibitors versus LC.

CONCLUSIONS

We found positive associations between exposure to all 4 medication classes and MC. Variations in endoscopic frequency by drug category indicate a potential impact of bias.

Microscopic colitis or functional bowel disease with diarrhea: a French prospective multicenter study

OBJECTIVES

To describe the characteristics of a cohort of patients with microscopic colitis (MC; lymphocytic (LC) or collagenous (CC) colitis) and to compare them with patients with functional bowel disorder with diarrhea (FBD-D).

METHODS

Between September 2010 and June 2012, patients fulfilling the following inclusion criteria were prospectively included in 26 centers in France: (i) having at least three bowel movements daily with change in stool consistency; (ii) duration of abnormal bowel habit >4 weeks; and (iii) normal or near-normal colonoscopy. Each patient underwent a colonoscopy and colonic biopsies. We compared the demographic, clinical, biological, and etiological characteristic of patients with MC (CC and LC) with those of control patients with FBD-D.

RESULTS

A total of 433 patients were included: 129 with MC (87 LC and 42 CC), 23 with another organic disease, and 278 with FDB-D, including patients with diarrhea and abdominal pain who met the criteria of Rome III (irritable bowel syndrome with diarrhea) and patients with functional diarrhea without abdominal pain. Logistic regression analysis identified the following independent predictors of MC: age >50 years (odds ratio (OR)=3.1, 95% confidence interval (CI)=1.6-5.9), presence of nocturnal stools (OR=2, 95% CI=1.1-3.9), weight loss (OR=2.5, 95% CI=1.3-4.7), duration of diarrhea <12 months (OR=2.0, 95% CI=1.1-3.5), recent introduction of new drugs (OR=3.7, 95% CI=2.1-6.6; P<0.0001), and the presence of a known autoimmune disorder (OR=5.5, 95% CI=2.5-12).

CONCLUSIONS

Age >50 years, the presence of nocturnal stools, weight loss, the introduction of a new drug, and the presence of a known autoimmune disease increase the probability of MC and thus the indication for colonoscopy with biopsies.

Observer variability in the histopathologic diagnosis of microscopic colitis and subgroups

The diagnosis of microscopic colitis (MC) is based on histologic findings and includes collagenous colitis (CC) and lymphocytic colitis (LC). Incomplete MC (MCi) denotes patients with chronic diarrhea and a normal endoscopy and morphological changes that do not completely meet the histologic criteria of LC or CC. The aim of this study was to investigate the intraobserver and interobserver agreement on the MC subtypes of CC, LC, and MCi and the ability to discriminate MCi from normal and inflammatory bowel disease/nonspecific reactive changes. A single hematoxylin and eosin-stained specimen from biopsies of the following 5 groups were randomly selected and blinded: CC, LC, MCi, inflammatory bowel disease, and normal. Three pathologists independently reviewed the specimens. The specimens were relabeled and reinterpreted 4 months later. Intraobserver and interobserver agreement was evaluated by κ statistics. κ values for intraobserver agreement were good for 5 diagnostic groups varying from 0.70 to 0.83 and very good when simplifying to only 3 diagnostic groups varying from 0.88 to 0.96, separating MC/MCi from non-MC. κ values for interobserver agreement varied from 0.60 to 0.75 for 5 diagnostic groups and 0.81 to 0.89 for 3 diagnostic groups. The study shows that the intraobserver and interobserver agreement is high for discriminating between MC/MCi and non-MC, whereas the ability to discriminate MCi from CC and LC is lower. A revision and consensus on the histologic criteria of the MC subtypes seem warranted.

Idiopathic microscopic colitis of rhesus macaques: quantitative assessment of colonic mucosa

Idiopathic chronic diarrhea (ICD) is a common cause of morbidity and mortality among juvenile rhesus macaques. While lesions may be absent at colonoscopy, the histopathologic evaluation of the biopsy specimens is consistent with human macroscopic colitis (MC). In this study, we developed an isotropic uniform random sampling method to evaluate macroscopic and microscopic changes and applied it on proximal ascending colon in monkeys. Colonic tissue and peripheral blood specimens were collected from six MC and six control juvenile macaques at necropsy. Uniform random samples were collected from the colon using punch biopsy tools. The volume of epithelium and lamina propria were estimated in thick (25 µm) sections using point probes and normalized to the area of muscularis mucosae. Our data suggests a significant increase of the Vs of the lamina propria (1.9-fold, P = 0.02) and epithelium (1.4-fold, P = 0.05) in subjects with MC. The average colonic surface mucosa area in the MC monkeys increased 1.4-fold over the controls (P = 0.02). The volume of the proximal colon in animals with MC showed a 2.4-fold increase over the non-diarrhea control monkeys (P = 0.0001). Cytokine, chemokine, and growth factor levels in peripheral blood were found to be correlated with the volume estimate of the lamina propria and epithelium. We found that ICD in macaques has features which simulates human MC and can be used as a spontaneous animal model for human MC. Furthermore, this developed sampling method can be used for unbiased preclinical evaluation of therapeutics in this animal model.

Microscopic colitis in patients with chronic diarrhea and normal colonoscopic findings in Southern China

BACKGROUND AND OBJECTIVES

Microscopic colitis includes lymphocytic colitis and collagenous colitis. The entity is considered as an important cause for unknown chronic diarrhea, but rarely reported in China before. This study aimed to determine the prevalence of microscopic colitis in patients with chronic diarrhea and normal colonoscopy findings in Southern China, and to reveal the clinical feature of microscopic colitis in these patients.

METHODS

Patients with chronic diarrhea and normal colonoscopic findings were enrolled from three hospitals in Southern China from January, 2009 to June, 2010. Multiple colorectal biopsies were obtained in these patients and histological examination was underwent with hematoxyin and eosin stain, Masson's trichrome stain and immunohistochemistry for tenascin to screen lymphocytic colitis and collagenous colitis. The clinical symptom and risk factor of microscopic colitis were assessed by comparing with controls. The diagnostic overlap between microscopic colitis and irritable bowel syndrome or functional diarrhea was also analyzed.

RESULTS

Randomly mucosal biopsies were performed in 613 patients with chronic diarrhea and normal or near normal colonoscopic finding. Fifty-nine cases of lymphocytic colitis and 28 cases of collagenous colitis were found by histological examination. The rates of rheumatoid arthritis in lymphocytic colitis group (15.4 %) and collagenous colitis group (14.3 %) were significant higher than in control group (2.2 %). Rheumatoid arthritis was confirmed as the risk factor of microscopic colitis by logistic regression analysis. There was no difference on the symptoms among the controls, patients with lymphocytic colitis, and patients with collagenous colitis. There were 13.8 % (12/87) of patients with microscopic colitis fulfilled Rome III criteria of irritable bowel syndrome and 42.5 % (37/87) fulfilled the criteria of functional diarrhea.

CONCLUSIONS

Microscopic colitis is not an uncommon disorder in Chinese population. Rheumatoid arthritis is the risk factor of microscopic colitis. Microscopic colitis has a symptomatic overlap with irritable bowel syndrome and functional diarrhea. It is reasonable to obtain multiple biopsies in patients with chronic diarrhea when the mucosa grossly normal at colonoscopy.

Systematic review: are lymphocytic colitis and collagenous colitis two subtypes of the same disease - microscopic colitis?

BACKGROUND

Despite similar clinical symptoms, collagenous colitis (CC) and lymphocytic colitis (LC) are considered two distinct disease entities.

AIM

To compare pathoanatomical findings, clinical presentations, risk factors, course of diseases and response to treatment in CC and LC to establish whether they could be subtypes of the same disease, microscopic colitis (MC).

METHODS

The MEDLINE was searched for CC, LC and MC, and clinical studies of >20 patients were included. Pooled results with 95% confidence intervals were calculated based on the number of patients.

RESULTS

An abnormal number of intraepithelial lymphocytes are found in 45% (40-50%) with CC, and an abnormal subepithelial collagen band in 16% (13-20%) with LC suggesting a histological overlap. The incidence of CC and LC has increased in parallel. Mean age (CC 63 years; LC 60 years) and clinical presentation are indistinguishable, and females are predominant in CC (77%; 75-79%) as well as LC (68%; 66-70%). Risk factors such as nonsteroid anti-inflammatory drugs consumption CC 39% (36-42%); LC 32% (29-35%) are similar and prevalence of concomitant autoimmune diseases such as coeliac disease (CC 5%; CI: 4-6% and LC 7%; CI: 6-9%) do not differ. Bile acid diarrhoea is highly prevalent in CC (41%; 37-45%) and LC (29%; 24-34%). The effect of budesonide is identical.

CONCLUSIONS

CC and LC could be considered histological subtypes of the same disease, MC. To facilitate recruitment to clinical trials, all MC patients could be included in future trials and stratified for subtypes.

Lymphocytic colitis and collagenous colitis: a review of clinicopathologic features and immunologic abnormalities

Lymphocytic colitis (LC) and collagenous colitis (CC), 2 histologic forms of microscopic colitis, were recognized as rare disease entities 4 decades ago. An increasing body of evidence accumulated in the past 40 years reveals increasing incidence and prevalence rates, a wide spectrum of clinical presentations, and several histologic variants. Although several recent randomized clinical trials confirmed the efficacy of oral budesonide in treating LC and CC, disease relapse after a short-duration treatment is common. Despite their common clinical presentations and well-defined histologic diagnostic criteria, there are only few studies on the immunologic abnormalities in colonic tissue. The aim of this review is to (1) familiarize the pathologists in general practice with histomorphology of LC and CC, including the rare histologic variants and the clinical implication associated with these 2 diagnoses, (2) summarize the data from recent randomized clinical trials of oral budesonide, and (3) review immunological studies on colonic tissue. Overall, immunologic abnormalities of colonic tissue seem to explain for the histomorphologic features and the clinical symptomatology of LC and CC. Advances in the understanding of the underlying immunologic abnormalities in the colonic tissue may help develop novel and effective therapies for these 2 diseases.

Microscopic colitis as a missed cause of chronic diarrhea

AIM: To determine the prevalence of increased intraepithelial lymphocytes, using immunohistochemistry in patients with normal colonoscopy and near normal biopsy.

METHODS: We retrospectively reviewed all non-malignant colon mucosal biopsies between 2005 and 2007, reported as normal, chronic inflammation or melanosis coli in patients who were undergoing routine colonoscopy. Immunohistochemistry using CD3 was performed on all mucosal biopsies and an intraepithelial lymphocyte count (IEL) was determined. Cases with an IEL count of ≥ 20 IELs per 100 surface epithelial cells were correlated with demographic, clinical and follow-up data. A further subgroup was evaluated for lymphocytic colitis.

RESULTS: Twenty (8.3%) of 241 cases revealed an IEL count ≥ 20. Six (2.5%) patients were identified as having lymphocytic colitis (P < 0.001), of whom, five were missed on initial evaluation (P = 0.01). Four of these five patients were labeled with diarrhea-predominant irritable bowel syndrome (IBS). On follow-up, three of the remaining 20 cases were diagnosed with malignancy (renal cell carcinoma and myelodysplastic syndrome) and one had an unknown primary tumor with multiple liver metastases. Two cases of collagenous colitis with an IEL count < 10 were included in this study. Increased IELs were not confined to patients with diarrhea as a primary presenting symptom, but were also present in patients with abdominal pain (n = 7), constipation (n = 3) and loss of weight (n = 1).

CONCLUSION: Immunohistochemistry using CD3 is of value in identifying and quantifying IELs for the presence of microscopic colitis in patients with diarrhea-predominant IBS.