Cardiac rather than intestinal-type background in endoscopic resection specimens of minute Barrett adenocarcinoma

Update on endoscopic diagnosis, management and surveillance strategies of esophageal diseases

In the last few decades, upper gastrointestinal endoscopy has become the most complementary test for investigation of esophageal diseases. Its accessibility and safety guarantee wide clinical utilization in patients with suspected benign and malignant diseases of the esophagus. Recent technological advances in endoscopic imaging and tissue analysis obtained from the esophagus have been useful to better understand and manage highly relevant diseases such as gastroesophageal reflux disease, eosinophilic esophagitis and esophageal cancer. Using endoscopy to elucidate esophageal disorders in children has been another field of intensive and challenging research. This editorial highlights the latest advances in the endoscopic management of esophageal diseases, and focuses on Barrett's esophagus, esophageal cancer, eosinophilic esophagitis, as well as esophageal disorders in the pediatric population.

Divergent expression of MUC5AC, MUC6, MUC2, CD10, and CDX-2 in dysplasia and intramucosal adenocarcinomas with intestinal and foveolar morphology: is this evidence of distinct gastric and intestinal pathways to carcinogenesis in Barrett Esophagus?

Dysplasia in Barrett esophagus has been recognized to be morphologically heterogenous, featuring adenomatous, foveolar, and hybrid phenotypes. Recent studies have suggested a tumor suppressor role for CDX-2 in the metaplasia-dysplasia-carcinoma sequence. The phenotypic stability and role of CDX-2 in the neoplastic progression of different types of dysplasias have not been evaluated. Thirty-eight endoscopic mucosal resections with dysplasia and/or intramucosal carcinoma (IMC) arising in Barrett esophagus were evaluated for the expression of MUC5AC, MUC6, MUC2, CD10, and CDX-2. The background mucosa was also evaluated. The results were correlated with morphologic classification and clinicopathologic parameters. Of 38 endoscopic mucosal resections, 23 had IMC and dysplasia, 8 had IMC only, and 7 had dysplasia only. Among dysplastic lesions, 73% were foveolar, 17% were adenomatous, and 10% were hybrid. Twenty of 23 cases with dysplasia and adjacent IMC showed an identical immunophenotype of dysplasia and IMC comprising 16 gastric, 3 intestinal, and 1 mixed immunophenotype. Three cases showed discordance of dysplasia and IMC immunophenotype. These findings suggest that most Barrett-related IMC cases are either gastric or intestinal, with phenotypic stability during progression supporting separate gastric and intestinal pathways of carcinogenesis. CDX-2 showed gradual downregulation of expression during progression in adenomatous dysplasia but not in foveolar or hybrid dysplasia, supporting a tumor suppressor role, at least in the intestinal pathway. CDX-2 was also found to be expressed to a greater degree in intestinal metaplasia compared with nonintestinalized columnar metaplasia. Consistent with CDX-2 as a tumor suppressor, this suggests that nonintestinalized columnar metaplasia may be an unstable intermediate state at risk for neoplastic progression.

Endoscopic characteristics of short-segment Barrett's esophagus, focusing on squamous islands and mucosal folds

BACKGROUND AND AIM

Endoscopic definitions of Barrett's esophagus (BE) vary among countries, mainly because of the difficulty in diagnosing short-segment BE (SSBE) endoscopically. The aim of this study was to investigate whether the endoscopic identification of squamous islands and the specific position of columnar epithelium helps improve the diagnosis of SSBE.

METHODS

First, we prospectively enrolled 100 consecutive patients with SSBE and evaluated the number of identified squamous islands in the columnar epithelium with different modalities: white light (WL), narrow band imaging (NBI), and iodine chromoendoscopy. Second, in another group of 100 consecutive patients with tongue-like SSBE, the correlation of the location of Barrett's mucosa to the esophageal longitudinal folds (ridge or valley) was evaluated endoscopically.

RESULTS

It was possible to detect squamous islands in 48, 71, and 75 patients by WL, NBI, and iodine chromoendoscopy, respectively. The detection rate of squamous islands by NBI or iodine chromoendoscopy was significantly superior to that by WL. Tongue-like SSBEs were predominantly found on the ridge of mucosal folds (71%), similar to the location of mucosal breaks (84%).

CONCLUSIONS

Squamous islands in the columnar epithelium were efficiently observed by NBI or iodine chromoendoscopy. SSBE was found more frequently on the ridges but not in the valleys of esophageal longitudinal mucosal folds. NBI endoscopic observation focusing on columnar epithelium with squamous islands on the ridges of distal esophageal folds may improve endoscopic detection of SSBE.

Columnar-lined esophagus without intestinal metaplasia has no proven risk of adenocarcinoma

Intestinal metaplasia in the columnar-lined esophagus (CLE) has long been recognized as the most significant histologic risk indicator for esophageal adenocarcinoma. Recent concern has been expressed, however, that nonintestinalized metaplastic columnar epithelia (cardiac epithelium in the esophagus) may also indicate risk. Of 2586 consecutive patients undergoing endoscopy and biopsy in the Foregut Surgery Department, we selected (a) 214 patients with a visible CLE who had systemic 4-quadrant biopsies at 1 to 2 cm intervals, with the most proximal biopsy straddling the squamocolumnar junction, and (b) 109 patients without systematic biopsy who had dysplasia or adenocarcinoma. In the first group, 187 (87.4%) patients had intestinal metaplasia, and 27 (12.6%) had cardiac epithelium. Dysplasia or adenocarcinoma was present in 55 patients, all with intestinal metaplasia; its presence was significantly higher than in the cardiac epithelium group, none of whom had dysplasia or adenocarcinoma (P=0.01). In the second group with limited sampling, 49 had only tumor tissue in the biopsy. Of 60 patients with nontumor epithelium, only 34 (56.7%) had residual intestinal metaplasia. We conclude that systematic biopsies of CLE as described in this study separate patients into those with and without intestinal metaplasia in such a manner as to remove the possibility of false-negative diagnosis of intestinal metaplasia. When intestinal metaplasia is absent using this biopsy protocol, the patient is at no or extremely low risk for dysplasia and cancer. When biopsies have a lower level of sampling of the segment of CLE, the absence of intestinal metaplasia cannot be interpreted as a true negative for intestinal metaplasia. Inadequate sampling is a powerful reason why the near absolute association between intestinal metaplasia and adenocarcinoma is not seen in some studies.

Bile acid and inflammation activate gastric cardia stem cells in a mouse model of Barrett-like metaplasia

Esophageal adenocarcinoma (EAC) arises from Barrett esophagus (BE), intestinal-like columnar metaplasia linked to reflux esophagitis. In a transgenic mouse model of BE, esophageal overexpression of interleukin-1β phenocopies human pathology with evolution of esophagitis, Barrett-like metaplasia and EAC. Histopathology and gene signatures closely resembled human BE, with upregulation of TFF2, Bmp4, Cdx2, Notch1, and IL-6. The development of BE and EAC was accelerated by exposure to bile acids and/or nitrosamines, and inhibited by IL-6 deficiency. Lgr5(+) gastric cardia stem cells present in BE were able to lineage trace the early BE lesion. Our data suggest that BE and EAC arise from gastric progenitors due to a tumor-promoting IL-1β-IL-6 signaling cascade and Dll1-dependent Notch signaling.

Hepatocyte paraffin 1 antigen as a biomarker for early diagnosis of Barrett esophagus

We evaluated hepatocyte paraffin 1 (HepPar1) antigen expression, a sensitive marker of small intestinal differentiation, in combination with morphologic features to demonstrate intestinal differentiation in cases equivocal for Barrett esophagus (BE). Clinicopathologic features and HepPar1 expression were recorded for 54 BE cases, 45 consistent with reflux esophagitis (RE) cases, and 65 "suspicious" for BE (SBE) cases. The SBE category included RE cases with 2 or more morphologic changes associated with BE or metaplastic reaction to injury (eg, multilayered epithelium, squamous islands, goblet cell mimickers, pancreatic metaplasia). HepPar1 was expressed in all 54 BE cases, 4 of 45 RE cases, and 24 of 65 SBE cases. In SBE cases, 2 or more morphologic changes were associated with HepPar1 expression in 37% of cases (24/65), 3 or more features in 59% (13/22), and 4 or more features in 100% (4/4) (P ≤ .004). The combination of certain morphologic changes and HepPar1 expression in clinically suspicious distal esophageal biopsy cases without goblet cells supports the presence of evolving intestinal metaplasia.

Chinese National Consensus on diagnosis and management of Barrett's esophagus (BE): revised edition, June 2011, Chongqing, China

To standardize the diagnosis and management of Barrett's esophagus (BE) in China, the Chinese Society of Gastroenterology convened the Second National Conference on BE in June 2011 in Chongqing, China. After intense discussion among experts in this field and an extensive review of the literature, a revised consensus on the diagnosis and management of BE was generated.

Esophageal disease and pathology

The following on esophageal disease and pathology contains commentaries on the varied definitions of Barrett's esophagus (BE); the optimal biopsy strategy in BE; reliable biomarkers for progression to neoplasia in BE; and the role of bone marrow stem cells in the morphogenesis of Barrett's esophagus.

A Clinical and Histopathologic Focus on Barrett Esophagus and Barrett-Related Dysplasia

Context.—Barrett esophagus is a metaplastic, premalignant lesion associated with approximately 0.5% annual incidence of progression to esophageal adenocarcinoma. Diagnosis and screening of Barrett esophagus and Barrett-related dysplasia relies on histologic evaluation of endoscopic mucosal biopsies, a process that is burdened with interobserver variability.

Objectives.—To review the histologic features and classification of Barrett esophagus and Barrett-related dysplasia, to discuss the underlying difficulties in diagnosis and pitfalls, and to provide a brief review of new developments related to therapeutic modalities for patients diagnosed with dysplasia.

Data Sources.—Sources include a review of relevant literature indexed in PubMed (US National Library of Medicine).

Conclusions.—In spite of interobserver variability, histologic assessment of dysplasia is currently the accepted method of surveillance, and subsequent patient management is dictated by this evaluation. Although not universal, endoscopic therapy is increasingly important in replacing esophagectomy for patients with high-grade dysplasia or early carcinoma.

The dichotomy in carcinogenesis of the distal esophagus and esophagogastric junction: intestinal-type vs cardiac-type mucosa-associated adenocarcinoma

Adenocarcinoma of the distal esophagus and esophagogastric junction continues to rise in incidence. An intestinal metaplasia (Barrett esophagus)-dysplasia-carcinoma sequence induced by gastroesophageal reflux disease is well established. However, a significant number of adenocarcinomas in the vicinity of the esophagogastric junction are seen in the background of gastric/cardiac-type mucosa without intestinal metaplasia. Thus, the aim of this study was to investigate the role of Barrett esophagus (intestinal-type mucosa) in the classification and prognosis of tumors of the distal esophagus and esophagogastric junction. Clinicopathological and molecular characteristics were examined in 157 consecutively resected adenocarcinomas of the distal esophagus and esophagogastric junction and were compared between tumors arising in association with intestinal-type and cardiac-type mucosa. Intestinal-type mucosa-associated adenocarcinomas were more likely to be associated with younger age (P=0.0057), reflux symptoms (P<0.0001), proximal location (P=0.0009), lower T stage (P<0.0001), fewer nodal metastases (P=0.0001), absence of lymphatic (P<0.0001), venous (P=0.0060) or perineural (P<0.0001) invasion. Histologically, intestinal-type mucosa-associated tumors were more likely to be low-grade glandular tumors (P=0.0095) of intestinal or mixed immunophenotype (P=0.015) and express nuclear β-catenin (P=0.0080), whereas tumors arising in a background of cardiac-type mucosa were more frequently associated with EGFR amplification (P=0.0051). Five-year overall survival rate was significantly higher in patients with intestinal-type mucosa-associated tumors (28 vs 9%, P=0.0015), although no survival benefit was seen after adjusting for potential confounders. Our findings support the theory that multiple distinct pathways of tumorigenesis exist in the vicinity of the esophagogastric junction, including one in which tumors arise from dysplastic intestinal metaplasia (intestinal pathway), and one potentially involving dysplasia of the cardiac-type mucosa (non-intestinal pathway). Additional studies are warranted to further clarify their pathogenesis and the molecular mechanisms involved.

MUC2 is a highly specific marker of goblet cell metaplasia in the distal esophagus and gastroesophageal junction

Currently, the American College of Gastroenterology requires identification of goblet cells in mucosal biopsies from the esophagus to diagnose Barrett esophagus (BE). Identification of goblet cells in mucosal biopsies is fraught with limitations such as sampling and interpretation error. One previous study by our group suggested that MUC2 expression in esophageal nongoblet columnar cells represents a late biochemical reaction in the conversion of mucinous columnar cells to goblet cells in BE. We conducted this study to evaluate the prevalence, sensitivity, and specificity of MUC2 positivity in nongoblet columnar epithelium for detection of goblet cells in the distal esophagus and gastroesophageal junction (GEJ) region. We also sought to identify associations between MUC2 positivity and clinical and endoscopic risk factors for BE. This analysis utilized mucosal biopsies of the distal esophagus or GEJ from 100 patients who participated in a community clinic-based study of patients with chronic gastroesophageal reflux disease evaluated prospectively in the western part of Washington state. We randomly selected 50 patients who had columnar epithelium with goblet cells, representing the study group and 50 patients without goblet cells, representing the comparison group. Immunohistochemistry for MUC2 was performed on samples in a blinded manner without knowledge of the clinical or endoscopic features of the patients. The presence of staining was noted in both goblet and nongoblet epithelium, both close to and distant from the mucosa with goblet cells, when the latter were present. All study patients showed MUC2 positivity in goblet cells. MUC2 was present in nongoblet columnar epithelium in 78% of study patients with goblet cells, but in only 4% of controls without goblet cells (P<0.0001) (sensitivity, 78%; specificity, 96% for goblet cell metaplasia). MUC2 was significantly more common in nongoblet columnar cells close to, rather than distant from, the mucosa with goblet cells (P<0.00001). Finally, MUC2 was significantly associated with endoscopic evidence of columnar metaplasia in the distal esophagus, and with known risk factors for BE, such as older age, white race, frequent heartburn, and elevated body mass index. We conclude that goblet cells likely develop from a field of MUC2-positive mucinous columnar cells, and as such, MUC2 represents a late event in the development of goblet cells. MUC2 staining in nongoblet columnar cells is a reasonably sensitive and highly specific marker for goblet cells in the distal esophagus and GEJ, and its presence is predictive of endoscopic columnar metaplasia of the esophagus, even in patients without goblet cells.

What the gastroenterologist needs to know about the histology of Barrett's esophagus

PURPOSE OF REVIEW

The purpose of this review is to provide clinicians with an up-to-date summary of the terminology, classification, biological characteristics, and limitations of pathology regarding Barrett's esophagus and associated neoplastic precursor lesions in order to optimize decision making when evaluating patients with this disorder.

RECENT FINDINGS

This review summarizes some of the advancements and controversies regarding the definition and diagnostic criteria for Barrett's esophagus, difficulties that arise when trying to differentiate esophageal versus gastric epithelium in gastroesophageal junction (GEJ) biopsies, the histology and biology of nondysplastic Barrett's esophagus including columnar metaplasia without goblet cells, and the limitations and diagnostic variability in interpretation of conventional and nonconventional types of dysplasia in Barrett's esophagus.

SUMMARY

The definition of Barrett's esophagus is controversial, particularly with regard to the need to identify goblet cells in esophageal biopsies. In most cases, morphologic evaluation of GEJ biopsies cannot help distinguish whether the columnar epithelium comes from the distal esophagus versus the proximal stomach. Metaplastic esophageal columnar epithelium that does not contain goblet cells nevertheless is biologically intestinalized, shows molecular abnormalities, and has been shown to be at risk for progression to cancer, but the magnitude of that risk is unknown. Interobserver agreement on the presence, grade, and type of dysplasia remains moderate at best, particularly in light of the recent recognition of nonconventional types of dysplasia, such as foveolar, serrated, and early crypt dysplasia, which make interpretation difficult. Close cooperation between clinicians and pathologists is essential in order to ensure proper interpretation of biopsy results and to provide optimal surveillance and treatment decisions.

Barrett's esophagus: a review of the literature

Barrett's esophagus (BE) is the premalignant lesion of esophageal adenocarcinoma (EAC) defined as specialized intestinal metaplasia of the tubular esophagus that results from chronic gastroesophageal reflux. Which patients are at risk of having BE and which are at further risk of developing EAC has yet to be fully established. Many aspects of the management of BE have changed considerably in the past 5 years alone. The aim of this review is to define the critical elements necessary to effectively manage individuals with BE. The general prevalence of BE is estimated at 1.6-3% and follows a demographic distribution similar to EAC. Both short-segment (<3 cm) and long-segment (≥3 cm) BE confer a significant risk for EAC that is increased by the development of dysplasia. The treatment for flat high-grade dysplasia is endoscopic radiofrequency ablation therapy. The benefits of ablation for non-dysplastic BE and BE with low-grade dysplasia have yet to be validated. By understanding the intricacies of the development, screening, surveillance, and treatment of BE, new insights will be gained into the prevention and early detection of EAC that may ultimately lead to a reduction in morbidity and mortality in this patient population.

Microscopic esophagitis and Barrett's esophagus: the histology report

Gastro-esophageal reflux disease (GERD) is the most common digestive disease in industrialized countries (Europe and North America) and is associated with microscopic changes in the squamous epithelium. However, biopsy is not presently included in the routine diagnostic flow chart of GERD. In contrast, esophageal biopsy is mandatory when diagnosing Barrett's esophagus. High quality histology reports are necessary to provide information on diagnosis and can also be important for research and epidemiological studies. It has been evident for decades that pathology reports vary between institutions and even within a single institution. Standardization of reporting is the best way to ensure that information necessary for patient management is included in pathology reports. This paper details the histological criteria for diagnosing GERD-associated microscopic esophagitis, other forms of esophagitis with specific features and columnar metaplasia in the lower esophagus (Barrett's esophagus). It provides a detailed description of appropriate sampling criteria, individual lesions and how they contribute to the histology report.

Current status of Barrett's esophagus research in Asia

In Western countries, the epidemiology of esophageal cancer has changed considerably over the past decades with a rise in the ratio of adenocarcinoma to squamous cell carcinoma. Although the prevalence of gastroesophageal reflux is increasing in Asia, the prevalences of Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC) have remained low in most Asian countries. The Asian Barrett's Consortium recently conducted a review of published studies on BE from Asia to assess the current status of BE research in Asia, and to recommend potential areas for future BE research in the region. Differences in study design, enrolled population, and endoscopic biopsy protocols used have led to substantial variability in the reported BE prevalence (0.06% to 19.9%) across Asia. In particular, some Japanese studies used diagnostic criteria that differed considerably from what was used in most Asian studies. As in Western countries, increased age, male sex, tobacco smoking, reflux symptoms, and erosive esophagitis have been found to be risk factors for BE in several case-control studies from Asia. The Prague C and M criteria, developed to provide better interobserver reliability in diagnosis and grading of BE, are currently under extensive evaluation in the Asian population. There is a need for standardized protocols for endoscopic and histopathologic diagnosis before initiating collaborative projects to identify etiologic determinants of BE and its ensuing malignant transformation. At present, data regarding the management and long-term outcome of BE are extremely limited in Asia. More studies of BE in this geographic area are warranted.

Barrett's esophagus: A historical perspective, an update on core practicalities and predictions on future evolutions of management

Interpretation of exploding knowledge about Barrett's esophagus is impaired by use of several conflicting definitions. Because any histological type of esophageal columnar metaplasia carries risk for esophageal adenocarcinoma, the diagnosis of Barrett's esophagus should no longer require demonstration of intestinal-type metaplasia. Endoscopic recognition and grading of Barrett's esophagus remains a significant source of ambiguity. Reflux disease is a key factor for development of Barrett's esophagus, but other factors must underlie its development, since it occurs in only a minority of reflux disease patients. Neither antireflux surgery nor proton pump inhibitor (PPI) therapy has major impacts on cancer risk. Within a year, a major trial should indicate whether low-dose aspirin usefully reduces cancer risk. The best referral centers have transformed the accuracy of screening and surveillance for early curable esophageal adenocarcinoma by use of enhanced and novel endoscopic imaging, visually-guided, rather than blind biopsies and by partnership with expert pathologists. General endoscopists now need to upgrade their skills and equipment so that they can rely mainly on visual targeting of biopsies on mucosal areas of concern in their surveillance practice. General pathologists need to greatly improve their interpretation of biopsies. Endoscopic therapy now achieves very high rates of cure of high-grade dysplasia and esophageal adenocarcinoma with minimal morbidity and risk. Such results will only be achieved by skilled interventional endoscopists. Esophagectomy should now be mainly restricted to patients whose cancer has extended into and beyond the submucosa. Weighing risks and benefits in the management of Barrett's esophagus is difficult, as is the process of adequately informing patients about their specific cancer risk.

Barrett's esophagus: Clinical issues

Barrett's esophagus has been defined conceptually as the condition in which any extent of metaplastic columnar epithelium that predisposes to cancer development replaces the stratified squamous epithelium that normally lines the distal esophagus. The condition develops as a consequence of gastroesophageal reflux disease. Barrett's metaplasia has clinical importance primarily because of its malignant predisposition, and virtually all of the contentious clinical issues in Barrett's esophagus are related in some way to its cancer risk. This article considers some key clinical issues that impact the management of patients with Barrett's esophagus.

Differences of immunophenotypic markers and signaling molecules between adenocarcinomas of gastric cardia and distal stomach

During the past decades, the subsites of gastric carcinoma underwent significant changes. The incidence of the adenocarcinoma at distal stomach has been decreased, whereas cardiac adenocarcinoma remained increasing in many countries. The aim of this study was to investigate the differences between gastric cardiac and distal adenocarcinomas. We detected expressions of cytokeratins (cytokeratins 7, 14, 19, and 20) and mucins (mucins 1, 2, and 5AC) by immunohistochemistry and signaling molecules (p38, mitogen-activated protein kinase-interacting kinase 1 (MNK1), extracellular signal-regulated kinase, Jun N-terminal kinase, and phosphoinositide 3 kinase) by reverse transcription-polymerase chain reaction in both groups. The incidence of mucin 2 expression was lower in total (50.0%) and advanced-stage cases (52.0%) with cardiac adenocarcinomas than those in distal cases with total (70.2%) and advanced stage (71.4%), respectively. However, the staining for cytokeratin 14 was also significantly higher in total or advanced-stage tumors from the cardia. Our data showed no significant difference of cytokeratin 7/cytokeratin 20 pattern between 2 groups, but cytokeratin 20 expression was significantly higher in advanced-stage carcinomas of the cardia (58.7%) than in distal ones with advanced stage (38.3%). A multivariate analysis demonstrated different relationships between immunophenotypic markers and pathologic parameters in adenocarcinomas of the cardia and distal stomach. Moreover, significantly lower expressions of MNK1 and p38 in cardiac tumors were also detected. In summary, we found significant differences in patterns of immunophenotypic markers and expressions of signaling molecules between the 2 groups. It is indicated that adenocarcinoma of the cardia was different in histotype and histologic origin from distal adenocarcinoma. The cardiac adenocarcinoma might be a special subtype or an independent entity of gastric carcinoma in China.

Diagnostic challenges in the pathologic evaluation of Barrett esophagus

CONTEXT

Barrett esophagus represents an unstable epithelium resulting from chronic gastroesophageal reflux disease. Patients with Barrett esophagus routinely undergo endoscopic examination to detect dysplasia and early carcinoma. Although appropriate classification of Barrett esophagus and neoplasia is usually straightforward, persistent esophageal inflammation may induce epithelial changes that mimic, or mask, dysplasia. Recent data also indicate that specific molecular changes occur in nondysplastic Barrett mucosa and herald the development of dysplasia and/or carcinoma.

OBJECTIVE

To describe problematic aspects of biopsy interpretation in tissue samples of the gastroesophageal junction and distal esophagus, including the diagnostic criteria for Barrett esophagus, the importance of the gastric cardia, and pitfalls to the diagnosis of dysplasia. Ancillary studies that have recently emerged as potential adjuncts to the evaluation of patients with Barrett esophagus will be briefly discussed.

DATA SOURCES

A comprehensive review of the relevant literature indexed in PubMed (National Library of Medicine) was performed.

CONCLUSIONS

Barrett esophagus is currently defined as the presence of intestinal metaplasia in samples obtained from an endoscopically evident abnormality in the distal esophagus. Diagnosis and grading of dysplasia in mucosal biopsies remain the most reliable method to assess risk for neoplastic progression, but its classification may be hindered by superimposed inflammatory changes and suffers from considerable interobserver variability. Therefore, immunohistochemical studies and molecular assessment for TP53, CDKN2A , and DNA content abnormalities have emerged as potential adjuncts to the detection of dysplasia.

Controversies in the diagnosis of Barrett esophagus and Barrett-related dysplasia: one pathologist's perspective

CONTEXT

athologists frequently assess esophageal biopsy specimens to “rule out Barrett esophagus,” as well as to assess for the presence or absence of dysplasia.

OBJECTIVE

To review some of the recent controversies in the diagnosis of Barrett esophagus and Barrett-related dysplasia.

DATA SOURCES

Sources were the author's experience and review of the English literature from 1978 to 2009.

CONCLUSIONS

Although goblet cells are required by the American College of Gastroenterology to confirm a diagnosis of Barrett esophagus, this definition might expand to include columnar-lined esophagus without goblet cells. The recognition of dysplasia in Barrett esophagus remains a difficult task for the surgical pathologist, with difficulties in distinguishing reactive epithelium from dysplasia, low-grade dysplasia from high-grade dysplasia, and even high-grade dysplasia from intramucosal adenocarcinoma.

Preferential up-regulation of heparanase and cyclooxygenase-2 in carcinogenesis of Barrett's oesophagus and intestinal-type gastric carcinoma

AIMS

Metaplastic changes secondary to chronic inflammation at the gastro-oesophageal junction and at the pyloric antrum are recognized as the premalignant conditions of Barrett's oesophageal adenocarcinoma and intestinal-type gastric carcinoma (GC), respectively. Heparanase (HPSE) and cyclooxygenase (COX)-2 have been proved to play critical roles in inflammation as well as in cancer. The aim was to examine the meaning of their expression in inflammation-related carcinogenesis.

METHODS AND RESULTS

First, expression of HPSE and COX-2 in 78 clinical tissues of Barrett's oesophagus was examined by immunohistochemistry and in situ hybridization. Their expression was increased during the metaplasia-dysplasia sequence with increased neovascularization. Successively, their expression in Barrett's dysplasia was compared with that of GC (22 cases of diffuse-type and 10 of intestinal-type). Interestingly, the expression pattern in Barrett's dysplasia was similar to that in intestinal-type GC, which mainly arises from chronic inflammation. Furthermore, cultured cell lines isolated from differentiated GC tissues, which are often found to be of intestinal-type, revealed up-regulated mRNA expression of HPSE and COX-2.

CONCLUSIONS

HPSE and COX-2 are preferentially up-regulated in Barrett's oesophagus and intestinal-type GC. These molecules may play an important role during the development of inflammation-related adenocarcinoma of the upper gastrointestinal tract.

The role of Cdx2 in Barrett's metaplasia

Metaplasia (or transdifferentiation) is defined as the transformation of one tissue type to another. Clues to the molecular mechanisms that control the development of metaplasia are implied from knowledge of the transcription factors that specify tissue identity during normal embryonic development. Barrett's metaplasia describes the development of a columnar/intestinal phenotype in the squamous oesophageal epithelium and is the major risk factor for oesophageal adenocarcinoma. This particular type of cancer has a rapidly rising incidence and a dismal prognosis. The homoeotic transcription factor Cdx2 (Caudal-type homeobox 2) has been implicated as a master switch gene for intestine and therefore for Barrett's metaplasia. Normally, Cdx2 expression is restricted to the epithelium of the small and large intestine. Loss of Cdx2 function, or conditional deletion in the intestine, results in replacement of intestinal cells with a stratified squamous phenotype. In addition, Cdx2 is sufficient to provoke intestinal metaplasia in the stomach. In the present paper, we review the evidence for the role of Cdx2 in the development of Barrett's metaplasia.

Foveolar type dysplasia in Barrett esophagus

Adenocarcinoma of the lower esophagus and esophagogastric junction is increasing in incidence in Western countries. A metaplasia (Barrett esophagus)-dysplasia-carcinoma sequence induced by gastroesophageal reflux disease is established. Two patterns of Barrett dysplasias have been described-adenomatous (type 1) and non-adenomatous (type 2 or foveolar/hyperplastic type). Interestingly, little is known about non-adenomatous dysplasia. Esophagogastrectomy cases from 41 patients with glandular dysplasia with and without associated invasive adenocarcinoma of the lower esophagus were evaluated for expression of MUC2, MUC5AC, CDX2, villin, Ki67 and p53. Results were correlated with sub-classification of the dysplasia into morphologic patterns of adenomatous vs foveolar vs hybrid type. In addition, clinicopathological parameters including the presence and extent of background intestinal metaplasia were also evaluated. Foveolar type dysplasia was present in 46% of the cases and thus, was more common than adenomatous type or hybrid type (both approximately 27%) dysplasia. Immunohistochemistry confirmed the histological stratification in all cases. Foveolar type dysplasia commonly expressed MUC5AC (P<0.12) but was consistently negative for markers of intestinal differentiation, MUC2, CDX2 and villin (all P<0.01). By contrast, adenomatous type dysplasia frequently displayed intestinal differentiation markers (all P<0.0001) Hybrid-type dysplasia was similar to adenomatous type dysplasia in showing expression of intestinal differentiation markers (P<0.01) and therefore could not be sustained as a separate category. In conclusion, our study provides evidence for a non intestinal pathway to neoplastic development in Barrett esophagus, that is, gastric metaplasia-foveolar dysplasia-adenocarcinoma.

History, molecular mechanisms, and endoscopic treatment of Barrett's esophagus

This report is an adjunct to the American Gastroenterological Association Institute's medical position statement and technical review on the management of Barrett's esophagus, which will be published in the near future. Those documents will consider a number of broad questions on the diagnosis, clinical features, and management of patients with Barrett's esophagus, and the reader is referred to the technical review for an in-depth discussion of those topics. In this report, we review historical, molecular, and endoscopic therapeutic aspects of Barrett's esophagus that are of interest to clinicians and researchers.

Intestinal differentiation in metaplastic, nongoblet columnar epithelium in the esophagus

Barrett esophagus (BE) is defined by the presence of metaplastic esophageal columnar epithelium with goblet cells within endoscopically recognizable areas of the esophagus. However, some carcinomas in BE, or from the gastroesophageal junction region, develop within mucosa devoid of goblet cells. However, the biologic properties, pathogenesis, and risk of malignancy of metaplastic, esophageal nongoblet columnar epithelium, is, essentially, unknown. In this study, 89 patients with metaplastic esophageal columnar epithelium were evaluated immunohistochemically for markers of intestinal differentiation, such as MUC2, DAS-1, Villin, and CDX2, a marker of gastric differentiation (MUC5AC), and Ki67, a marker of cell proliferation. Of the 89 patients, 59 had columnar metaplasia with goblet cells (BE), which were further separated into low-density goblet cell and high-density goblet cell groups based on the percentage of crypts with goblet cells, and 30 patients had columnar metaplasia of the esophagus without goblet cells. As controls, gastric biopsies from 19 age and sex matched patients without esophageal or gastric pathology were used. The rate of positivity of the markers and the location of Ki67 staining was evaluated only in non-goblet columnar epithelium from all patient groups. Patients with metaplastic esophageal columnar epithelium without goblet cells showed positivity for MUC5AC, MUC2, DAS-1, Villin, and CDX2 in 100%, 0%, 30%, 17%, and 43% of cases, respectively. 17% of cases showed aberrant surface Ki67 positivity. These values were significantly higher than gastric controls, which showed absence of staining for all markers except MUC5AC (100%). In patients with metaplastic esophageal columnar epithelium with goblet cells (BE) a significant increased rate of staining was observed for all markers, except MUC5AC. In addition, both MUC2 and surface Ki67 staining were significantly increased in BE patients with high-density goblet cells versus those with low-density goblet cells. In a separate analysis in which metaplastic esophageal nongoblet epithelium was evaluated in areas of mucosa devoid of goblet cells compared with areas of mucosa with goblet cells, from patients who had goblet cells elsewhere in the mucosa (N=59), no significant differences were observed with regard to the percentage of cases that stained with any of the markers in the nongoblet epithelium in areas devoid of goblet cells, similar to the patient group with metaplastic esophageal epithelium without goblet cells (N=30). Similar to above, in all cases, expression of intestinal markers increased in areas of mucosa adjacent to goblet cells. This study provides evidence that metaplastic esophageal columnar epithelium without goblet cells shows phenotypic evidence of intestinal differentiation and supports the theory that squamous epithelium converts initially to nongoblet columnar epithelium before goblet cell metaplasia. Further prospective studies are needed to evaluate the pathogenetic sequence, natural history, and risk of malignancy of metaplastic esophageal nongoblet epithelium.

Adenocarcinoma in Barrett mucosa treated by endoscopic mucosal resection

Adenocarcinoma and dysplasias are recognized complications of Barrett mucosa. In the past, the treatment for this carcinoma was esophagectomy. However, new techniques, including endoscopic mucosal resection, sometimes replace esophagectomy and are becoming standard procedures in clinical practice, not just in major medical centers. Pathologists must learn to handle these specimens, which have extensive artifacts. Also, Barrett mucosa has duplicated stromal layers beneath the mucosa that include a new lamina propria and a new muscularis mucosae. We must be aware of these peculiarities because of staging implications. Regardless of new technology, the diagnostic approach to dysplasia depends on the light microscopic interpretation, which is not as reliable or consistent as one would wish. Hopefully, better diagnostic criteria will arise, and perhaps a new histologic stain or a molecular or genetic test will emerge that complements "our eyeballs."

Definition of Barrett's esophagus: time for a rethink--is intestinal metaplasia dead?

The definition of Barrett's esophagus (BE) varies worldwide, particularly with regard to the need to identify goblet cells in esophageal biopsies in order to diagnose this condition. Problems related to the need to identify goblet cells to diagnose BE include the facts that goblet cells are uncommon in pediatric patients with BE, a small percentage of adults with columnar metaplasia of the esophagus do not contain goblet cells, the chances of detecting goblet cells are proportional to the length of columnar metaplasia, sampling error is common, and interpretation and differentiation of goblet cells vs. pseudogoblet cells may be difficult in some circumstances. In addition, goblet cells have been shown to wax and wane over the natural history of BE. Recent studies suggest that the background nongoblet epithelium in BE is biologically intestinalized, and shows a variety of molecular abnormalities similar to the goblet cell-containing epithelium. In addition, several retrospective and outcome studies suggest a well-defined risk of neoplasia in patients with esophageal columnar metaplasia, but without goblet cells. There are important clinical and economic implications to these findings and also with regard to the definition of BE. This review provides evidence to suggest that a diagnosis of BE should not require demonstration of goblet cells in mucosal biopsies, and offers considerable data to support the notion that a nongoblet epithelium is also at risk of malignancy. Guidelines for the diagnosis of BE need to consider revisions that take into account new data regarding nongoblet cell epithelium in BE, and the difficulties in recognizing columnar metaplasia that measures less than 1 cm in length.

Endoscopic definition of esophagogastric junction for diagnosis of Barrett's esophagus: importance of systematic education and training

The diagnosis of Barrett's esophagus (BE) requires an accurate recognition of the columnar-lined esophagus at endoscopy. However, a universally accepted standardized endoscopic grading system of BE was lacking prior to the development of the Prague 'circumferential and maximal' criteria. In this system, the landmark for the esophagogastric junction (EGJ) is the proximal end of the gastric folds, not the distal end of the palisade vessels, which are used to endoscopically identify the EGJ in Japan. Although the circumferential and maximal criteria are clinically relevant, an important shortcoming of this system may be failure to identify short-segment BE, a lesion that is found frequently in the Japanese. To compare the diagnostic yield for BE when using the palisade vessels versus gastric folds as a landmark for the EGJ, we evaluated interobserver diagnostic concordance. The endoscopic identification of the EGJ using both landmarks resulted in unacceptably low kappa coefficients of reliability. However, there was a statistically significant improvement after the participants were thoroughly trained in identification of the EGJ during the endoscopic study. Although it remains controversial which landmark is better for the endoscopic diagnosis of BE, it is important to systematically educate and train endoscopists in order to improve diagnostic consistency in patients with BE.

Barrett esophagus: histology and pathology for the clinician

The incidence of adenocarcinoma of the esophagus and gastroesophageal junction has increased dramatically over the past 30 years. The major precursor to this type of adenocarcinoma is Barrett esophagus, which is defined as the conversion of normal squamous epithelium into metaplastic columnar epithelium. Abundant evidence suggests that adenocarcinoma in the setting of Barrett esophagus develops via a progressive sequence of histological and molecular events. Consequently, patients with Barrett esophagus routinely undergo endoscopic surveillance for early detection of neoplasia. Histological evaluation of mucosal biopsy samples from the esophagus and gastroesophageal junction for identification of goblet cells and evaluation of the presence, grade and extent of dysplasia is the mainstay of risk assessment for these patients. This Review provides physicians with a summary of the pertinent, clinically relevant histological features of Barrett esophagus and its neoplastic complications. The histology of Barrett esophagus and the gastroesophageal junction is summarized, and an overview of information necessary to interpret pathology reports from patients either with or without endoscopic evidence of Barrett esophagus is provided to appropriately guide management of patients. Close interaction between the clinician and the pathologist is essential for proper interpretation of biopsy results and to provide optimal surveillance or treatment strategies.

Nonadenomatous dysplasia in barrett esophagus: a clinical, pathologic, and DNA content flow cytometric study

Rarely, dysplasia in Barrett's esophagus (BE) is composed of crypts lined by cuboidal-shaped cells that contain a centrally located nucleus, markedly increased nuclear/cytoplasmic ratio, but without nuclear stratification characteristic of conventional "adenomatous" dysplasia. The aim of this study was to evaluate the clinical and pathologic features, natural history, and DNA content flow cytometric abnormalities of BE patients with non-adenomatous dysplasia (NAD) in a cohort of BE patients enrolled in a prospective surveillance program. Eighteen patients with NAD identified over a 6 year period, in a cohort of 270 consecutive patients with BE and without esophageal adenocarcinoma (EA) at baseline, were evaluated for clinical and pathologic features, including association with conventional adenomatous dysplasia and EA, DNA content flow cytometric abnormalities (tetraploidy and aneuploidy) and outcome, over a mean follow-up period of 4.1 years. The findings in the 18 study patients were compared to those in the 252 remaining (control) patients without NAD. Control patients included 228 with metaplasia/indefinite for dysplasia, and 24 with conventional adenomatous dysplasia (13 low-grade, 11 high-grade). The prevalence rate of NAD in our BE cohort was 6.7% Of the 18 study patients, there were 17 were males and 1 female of mean age 66.7 years. The mean length of BE was 3.9 cm NAD foci were associated with goblet or non-goblet epithelium in 62% and 38% of cases, respectively. Ninety-four percent of patients with NAD (17/18) also had conventional adenomatous dysplasia (four with low-grade, 13 with high-grade) elsewhere in the esophagus at the same endoscopic procedure as the one that detected NAD. Patients with NAD had a significantly shorter length of BE compared to control patients with conventional adenomatous dysplasia (N=24) (p=0.03). Patients with NAD also showed a significantly higher rate of DNA content flow cytometric abnormalities compared to the entire cohort of control patients (38% vs. 11%, p=0.05). However, no significant differences regarding either flow cytometric abnormalities or progression to EA were found when the NAD patients were compared only to the 24 controls with conventional adenomatous dysplasia. NAD is a high grade histologic variant of intraepithelial neoplasia that is episodic in nature, and shows a high association with conventional adenomatous high-grade dysplasia.

Metaplastic esophageal columnar epithelium without goblet cells shows DNA content abnormalities similar to goblet cell-containing epithelium

OBJECTIVES

The mucosa of patients with columnar-lined esophagus recognized on endoscopy usually shows epithelium with and without goblet cells. Columnar epithelium with goblet cells ("Barrett's esophagus") is generally believed to represent a premalignant lesion and has been shown to contain DNA abnormalities. However, the biological properties of non-goblet columnar epithelium remain unknown. The purpose of this study was to determine the DNA content properties of non-goblet epithelium in patients with metaplastic columnar epithelium of the esophagus.

METHODS

Mucosal biopsies of the esophagus from 68 patients with columnar metaplasia of the esophagus (22 without goblet cells and 46 with goblet cells) and 19 patients with normal gastric mucosa (controls) were histologically evaluated for the density of goblet cells. The latter group was divided into low-density, high-density, and very high-density goblet cell subgroups. Tissue sections of non-goblet epithelium and goblet cell epithelium (where present) were evaluated by image cytometry, and high-fidelity DNA histograms were created to indicate the G0/G1 peak DNA index (DI), DNA content heterogeneity index (HI), and the percentage of cells with DNA exceeding 5N (5N-EC). G0/G1 peaks with DI>1.1 were considered aneuploid.

RESULTS

Normal gastric controls showed a mean peak DI of 1.02+/-0.03 and an HI of 11.6+/-0.7. None of the controls revealed aneuploidy or 5N-EC. Patients with metaplastic columnar epithelium with goblet cells showed a DI of 1.15+/-0.12, HI of 18.2+/-2.1, mild aneuploidy in 54% of the cases, and 5N-EC in 15% of the cases, all of which were significantly higher than in controls. Patients with metaplastic columnar epithelium without goblet cells showed DNA content results statistically similar to those of patients with metaplastic columnar epithelium with goblet cells, and also revealed significantly higher values compared with those of controls. Furthermore, there were no significant differences in any of the key DNA content abnormalities between non-goblet and goblet cell-containing epithelium in patients with metaplastic columnar epithelium with goblet cells, or between these two types of epithelium according to the density of goblet cells.

CONCLUSIONS

DNA content abnormalities occur with equal frequency and extent in metaplastic columnar epithelium of the esophagus without goblet cells compared with metaplastic columnar epithelium with goblet cells. These findings suggest that metaplastic non-goblet columnar epithelium of the esophagus may have neoplastic potential.

Editorial: Defining a bad Barrett's segment: is it dependent on goblet cells?

The identification of patients with "bad Barrett's" who are at risk of neoplastic progression is a vital and pressing task. The view that specialized intestinal metaplasia with goblet cells is the predominant preneoplastic phenotype has had wide, but by no means universal, acceptance. An important caveat is presented in the thoughtful paper by Liu et al. in this issue. Of 68 patients with columnar metaplasia, 22 patients had no goblet cells identified and 46 had goblet cells in their biopsies. In both groups there were chromosomal and DNA content abnormalities and genetic instability. However, there were no significant differences between these cellular DNA abnormalities in the two groups. Both were significantly different from gastric controls. Thus, all metaplasia in the columnar-lined esophagus may already be on the path to cancer.