Histology of the gastroesophageal junction: an autopsy study

The utility of cytokeratins 7 and 20 (CK7/20) immunohistochemistry in the distinction of short-segment Barrett esophagus from gastric intestinal metaplasia: Is it reliable?

Background

The purpose of the present correlative immunohistochemical study was to assess the utility of cytokeratin (CK7 and CK20) expression in the diagnosis of short-segment Barrett esophagus, particularly its efficacy in differentiating Barrett mucosa from intestinal metaplasia of the gastric cardia and corpus.

Methods

Two groups of endoscopic biopsy specimens were examined, including 20 endoscopic biopsy specimens of short-segment Barrett esophagus (Group A) and equal number exhibiting Helicobacter pylori associated intestinal metaplasia of the gastric cardia and corpus (Group B). All were investigated by immunohistochemistry using the standard ABC method for CK7 and CK20 expression. Fisher's exact test was used for statistical analysis of Barrett CK7/20 and gastric CK7/20 patterns between the groups.

Results

The anticipated pattern of reactivity in Barrett mucosa (CK7: strong diffuse positivity in superficial and deep glands; CK20: positivity in surface epithelium and superficial glands) was seen in 2 cases of Group A specimens. The expected gastric pattern (CK7: patchy immunostaining with variable involvement of deep glands; CK20: patchy immunostaining of superficial and deep glands in incomplete intestinal metaplasia / absence of CK7 immunoreactivity with strong CK20 staining in superficial and deep glands in complete intestinal metaplasia) was seen in 8 cases of Group B specimens. The respective sensitivity and false-negativity values of CK7/20 staining for Barrett pattern in Group A were 10% and 90%, respectively. These values for gastric pattern in Group B were 40% and 60%, respectively. The specificity and false-positivity values of both patterns were same (100% and 0%, respectively). There was no statistically significant difference for Barrett pattern between the two groups (P = 0.487), while the observation of gastric pattern was significantly higher in Group B than in Group A (P = 0.02).

Conclusions

We concluded that these hypothesized and recently applied diagnostic criteria involving CK7 and CK20 immunoreactivity are not reliable in distinguishing short-segment Barrett esophagus from intestinal metaplasia as seen in gastric cardia and corpus.

Cdx2 as a marker of epithelial intestinal differentiation in the esophagus

The histologic diagnosis of Barrett's esophagus requires the presence of goblet cells, but this finding may not be the earliest indicator of intestinal metaplasia. We used immunohistochemistry to detect Cdx2, a transcriptional regulator important in the early differentiation and maintenance of intestinal epithelium, in 134 esophageal biopsy or resection specimens, including 62 with junctional-type epithelium (13 of which had equivocal histologic features of Barrett's epithelium), 34 with Barrett's epithelium without dysplasia, and 38 with Barrett's epithelium and dysplasia or carcinoma (13 low-grade dysplasias, 19 high-grade dysplasias, and 6 adenocarcinomas). We also performed PAS-alcian blue staining (pH 2.5) on adjacent sections. Cdx2 was observed in all cases of Barrett's epithelium. In some dysplasias (chiefly high-grade) and adenocarcinomas, there was diminution or focal loss of detectable protein. Cdx2 was detected in 20 of 62 cases (30%) of junctional-type epithelium, including 10 of 13 (77%) with equivocal histologic features of Barrett's epithelium. Acid mucin was present in goblet cells and non-goblet columnar cells in all cases of Barrett's esophagus and in non-goblet columnar cells in 48 of 62 cases (77%) with junctional-type epithelium only, including 17 of 20 (85%) that were Cdx2 positive and 31 of 42 (74%) that were Cdx2 negative. These results provide evidence that Cdx2 protein is a sensitive marker of intestinal metaplasia in the upper gastrointestinal tract and may be useful in detecting histologically equivocal cases of Barrett's esophagus. Cdx2 is present in dysplasia and adenocarcinoma, with some loss of protein primarily in high-grade dysplasia and adenocarcinoma. Acid mucin in non-goblet columnar cells is a common feature of Barrett's and junctional-type epithelium and may not always be indicative of intestinal metaplasia.

Inflammation in the cardia

The detection of chronic inflammation and intestinal metaplasia at the gastric side of a normal-appearing esophagogastric junction started active research on gastric cardia pathology. The main causes for this interest have been the increasing incidence of gastroesophageal reflux disease (GERD) and cardia adenocarcinoma. Many controversies still exist. It is even controversial whether noninflamed gastric cardia epithelium is a normal structure present at birth or an acquired lesion as a consequence of GERD. Similarly, the pathogenesis of chronic inflammation and intestinal metaplasia of gastric cardia are a matter of debate. Some researchers consider these lesions to be a consequence of Helicobacter pylori infection, whereas others think that chronic cardia inflammation and intestinal metaplasia are consequences of GERD. In this paper we review recent published studies in this field.

Histologic classification of patients based on mapping biopsies of the gastroesophageal junction

This study consists of 959 consecutive patients in whom endoscopic biopsies were taken according to a protocol that permitted mapping and measurement of epithelial types in the gastroesophageal region. The epithelial types were classified as normal (oxyntic and squamous) and questionably abnormal (oxyntocardiac, cardiac, intestinal) by strict histologic criteria. Patients were classified into four groups based on the length of histologically defined abnormal glandular epithelium in the measured biopsies. A total of 811 (84.6%) patients had 0 to 0.9 cm of questionably abnormal columnar epithelium between normal oxyntic mucosa and squamous epithelium. Of these, 161 (19.9%) patients had no abnormal epithelium, 158 (19.4%) patients had oxyntocardiac mucosa, 372 (45.9%) patients had cardiac mucosa, and 120 (14.8%) patients had intestinal metaplasia. A total of 148 (15.4%) patients had >or=1 cm of abnormal columnar epithelium. All but one patient in this group had cardiac or intestinal epithelia. The prevalence of intestinal epithelium increased progressively with increasing length of abnormal columnar epithelium, being present in 70.4% in the 1- to 2-cm group, 89.5% in the 3- to 4-cm group, and 100% with in the >or=5 cm group. We propose a histologic grading system of biopsies based on these findings.

Histology of gastroesophageal junction in fetal and pediatric autopsy

CONTEXT

There is much debate over whether the gastric cardia exists from birth as a normal structure or is a metaplastic structure that develops as the result of gastroesophageal reflux disease. This question has become a matter of concern since the incidence of adenocarcinoma at the gastroesophageal junction has been increasing rapidly in the Western world for more than 2 decades. Various groups of investigators have tried to clarify this matter by examining the histology of the gastroesophageal junction in autopsy cases, and there have been striking discrepancies in their findings. In one group, it was observed that cardiac mucosa was present in all pediatric autopsies. On the contrary, another group concluded that pure cardiac mucosa was absent in 56% of their autopsy cases.

OBJECTIVE

Without regard to the definition of the cardiac mucosa, we focused on the distance between the squamocolumnar junction and the most proximal parietal cells to elucidate the histologic features of the gastroesophageal junction on the gastric side.

DESIGN

The entire gastroesophageal junction and the proximal part of the stomach from 23 fetal and pediatric autopsies were mapped. We measured the distance from the squamocolumnar junction to the most proximal parietal cells identified. The extent of the transitional zone, defined as the mucosa between the squamocolumnar junction and the fundic mucosa, was also evaluated.

RESULTS

The transitional zone was identified in 78% of cases, and it always harbored some scattered parietal cells in mucous glands. The parietal cells were consistently identified adjacent to the squamocolumnar junction in all cases. Although the transitional zone in fetal stomach was usually composed of several pits of foveolar epithelium without glandular portions, it contained glandular structures in the pediatric cases.

CONCLUSIONS

The mucosa composed of pure mucous cells does not exist as a normal developmental structure.

Histology of Barrett's esophagus and dysplasia

This article explores issues related to the diagnosis of Barrett's esophagus (BE) in endoscopic biopsies and dysplasia in Barrett's epithelium. The definitions of BE, including long- and short-segment BE, are reviewed, with an emphasis on the significance of intestinal metaplasia (IM). IM of the gastroesophageal junction and cardia is reviewed and problems in its distinction from short-segment BE are discussed. In addition, the article reviews the classification of dysplasia in Barrett's mucosa, with reference to problematic areas, such as sampling error and interobserver variability. Biomarkers and their role in the diagnosis of dysplasia and stratification of risk are summarized.

The gastric cardia: to be or not to be?

The origin and biologic significance of cardiac gastric mucosa are controversial. Traditionally, it has been considered native mucosa and part of normal foregut development. It has been recently suggested that cardiac mucosa is present only as a metaplastic response to gastroesophageal reflux disease and therefore always abnormal. We evaluated the esophagogastric junction in 100 pediatric autopsy samples to determine the existence, characteristics, and length of pure cardiac mucosa at different ages. No patient had a history of gastroesophageal reflux disease. Cardiac mucosa immediately distal and contiguous to the esophageal squamous mucosa was identified in all 100 samples, varying in length from 0.1 to 3 mm; the mean length was 1 mm. There was an inverse correlation between patient age and length of cardiac mucosa; gender had no influence on measured length. Three patients had mild to moderate histologic esophagitis; two had gastritis. No metaplastic features or Helicobacter pylori were identified. These findings support the concept that there is a normal, variably narrow developmental zone at the esophagogastric junction covered by cardiac mucosa and is present at birth. When cardiac type mucosa is found in biopsy material, it does not necessarily represent evidence of a mucosal metaplastic response to gastroesophageal reflux disease.

Barrett's esophagus and Barrett's-related dysplasia

Barrett's esophagus is a complication of chronic gastroesophageal reflux disease and can be diagnosed when there is an endoscopic abnormality in which a biopsy shows evidence of specialized columnar epithelium, characterized by the presence of acid mucin-containing goblet cells. Much of the controversy in this body of literature relates to the complex anatomy of the esophagogastric junction and the difficulty in precisely identifying this landmark at endoscopy. By definition, in Barrett's esophagus, the squamocolumnar junction is proximal to the esophagogastric junction. Although fundic-type or cardiac-type (junctional) columnar epithelium may be present in Barrett's esophagus, it is only the presence of specialized columnar epithelium that is diagnostic of this condition. Patients with Barrett's esophagus are at risk of progressing to esophageal dysplasia and adenocarcinoma. There are several problems with using dysplasia as a marker for increased cancer risk in these patients, including problems with sampling error and intra- and interobserver variation in the recognition of dysplasia. It may be difficult to distinguish regenerative epithelial changes from dysplasia, low-grade from high-grade dysplasia, and high-grade dysplasia from intramucosal adenocarcinoma. Finally, there are relatively few prospective data evaluating the natural history of high-grade dysplasia. The management of patients with Barrett's-related dysplasia is controversial and varies from institution to institution. Future emphasis should be on cost-effective techniques for sampling as much of the esophageal mucosa as possible in patients who are at the highest risk of progressing to dysplasia and adenocarcinoma. Identification of biomarkers that identify such patients before the histologic recognition of dysplasia will be an area of intensive research.

Different Patterns of Cytokeratin Expression in Barrett's Esophagus–What is Beyond?

Barrett's esophagus (BE) was recently defined by the presence of metaplastic intestinal mucosa (specialized columnar epithelium) in the distal esophagus. However, different epithelial types that were classified by histological criteria occur at the gastro-esophageal region. The purpose of this study was to evaluate the expression of different subtypes of cytokeratins in Barrett's mucosa (BM) and to contribute to the discussion about the significance of cytokeratin expression patterns within the gastro-esophageal junction. Immunohistochemical detection of a wide spectrum of cytokeratins (CK7, CK10, CK19, CK20, CKHW, CK116 and CKAE1/AE3) was performed in bioptic samples obtained from 10 adults with BE and in nine samples of gastric mucosa from the same patients. Cytokeratin immunoreactivity of epithelial cells appearing in BM was particularly dependent on the differentiation degree of these cells. Less differentiated cells were positive for CK7 and CK10, as were the cells of the necks of gastric mucosa and the ducts of esophageal glands. In contrast, differentiated goblet cells showed only weak or negative immunoreactivity for CK7 and CK10. CK20 was positive predominantly in superficial parts of BM. Immunostaining with antibodies detecting a wider spectrum of cytokeratins (CK116, CKAE1/AE3) revealed prominent irregularities, particularly regarding the intensity of immunoreaction. BM showed only weakly positive staining for high molecular weight keratins. Our findings suggest that the mode of CK expression in BM is closely related to the differentiation degree of cells forming BM, and that the cytokeratin inmmunoreactivity pattern in BM is similar to that in the cells forming the necks of gastric glands and ducts of esophageal glands. However, it differs from squamous epithelium of esophageal mucosa.

Carditis is associated with Helicobacter pylori-induced gastritis and not reflux esophagitis

Pathogenesis of chronic inflammation at the gastric cardia is not yet clear. It is controversial whether cardiac-type mucosa is normal structure at the cardiac region. Therefore, we studied the existence of correlations between carditis, infection, and gastroesophageal reflux disease, and determined the prevalence of cardiac mucosa at the endoscopically defined cardiac region. Gastric biopsy specimens were analyzed from 27 patients with reflux esophagitis and 30 subjects without reflux esophagitis. Carditis was not associated with reflux esophagitis, but with infection. Moreover, the degree of gastritis and atrophy at the cardia were closely related to those of the antrum and body. Cardiac mucosa was not always present in the endoscopically defined cardiac region, and its prevalence was positively correlated with gastritis and atrophy grade of the cardia and age. In conclusion, -induced pangastritis may lead to the development of carditis, which is associated with occurrence of cardiac-type mucosa at the cardiac region.

Prevalence of mabDAS-1 positivity in biopsy specimens from the esophagogastric junction

OBJECTIVE

Intestinal metaplasia (IM) is a precursor for malignancies at the esophagogastric junction. A monoclonal antibody, mAbDAS-1, can probably identify cellular characteristics of IM before the appearance of goblet cells. The aim of this study was to examine the prevalence of mAbDAS-1 positivity in biopsies from the squamocolumnar junction (SCJ) and to correlate this positivity with the presence of IM and clinical findings.

METHODS

In 559 patients, reflux symptoms were scored, and the presence of reflux esophagitis and hiatus hernia was evaluated during endoscopy. Two biopsy specimens were obtained from the SCJ. In a subset of patients (n = 99), biopsies from the endoscopically defined cardiac region (2 cm distal to proximal margin of gastric folds) were available. Biopsy specimens were stained with hematoxylin and eosin, Alcian Blue, modified Giemsa, and mAbDAS-1.

RESULTS

mAbDAS-1 positivity was observed in the SCJ biopsies of 201 of 486 (41.4%) patients without IM and in 64 of 73 (87.7%) patients with IM. Patients without IM but with antibody positivity showed similar histological characteristics as patients with IM at the SCJ. Biopsies of 123 of 559 patients (22%) revealed a columnar-cuboidal epithelium, which was found to be mAbDAS-1 positive in 64.2% (77 of 123). Tissue specimens from the cardiac region without IM stained positive in 14.2% (13 of 91), 12 of those also stained at the SCJ.

CONCLUSIONS

In patients without IM, a high prevalence of mAbDAS-1 positivity was observed. Biopsies of these patients showed similar histological characteristics as patients with IM. Although not all patients exhibiting this reactivity may develop IM, mAbDAS-1 reactivity may help in the understanding of the histogenesis of IM at the SCJ.

Cytokeratin and DAS-1 immunostaining reveal similarities among cardiac mucosa, CIM, and Barrett's esophagus

OBJECTIVE

The normal histology at the gastroesophageal junction, and in particular the nature of cardiac mucosa, remains in dispute. Likewise, the relationship of intestinal metaplasia at the gastroesophageal junction (CIM) to Barrett's and intestinal metaplasia of the stomach (GIM) is unclear. The aim of this study was to assess the immunostaining characteristics of cardiac mucosa and CIM and compare their staining pattern with that of other foregut mucosal types. We hypothesized that the immunostaining patterns of these foregut tissues would provide insight into the nature and etiology of cardiac mucosa and CIM.

METHODS

Paraffin-embedded biopsy specimens from 50 patients with normal antral or fundic mucosa, cardiac mucosa, squamous mucosa, CIM, GIM, or Barrett's were obtained and immunostained with a panel of monoclonal antibodies including those for cytokeratins 7 and 20 (CK7/CK20) and DAS-1.

RESULTS

Biopsies from normal gastric antral and fundic mucosa and squamous esophageal mucosa all showed a non-Barrett's type CK7/CK20 immunostaining pattern, whereas in 85% of patients, cardiac mucosa had a Barrett's type CK7/CK20 pattern (p < 0.001). A Barrett's type CK7/ CK20 staining pattern was seen in 100% of Barrett's, 78% of CIM, and 0% of GIM patients. Likewise, DAS-1 staining was similar in patients with CIM and Barrett's and significantly different in patients with GIM.

CONCLUSIONS

Cytokeratin immunostaining of cardiac mucosa demonstrates significant differences from recognized normal gastric and esophageal mucosa but a similarity to Barrett's. This suggests that cardiac mucosa, like Barrett's, may be acquired. Likewise, immunostaining similarities between CIM and Barrett's biopsies point to the possibility of a reflux etiology for CIM in some patients.

Immunohistochemical study of neuroendocrine cells at the gastric cardia mucosa

BACKGROUND/AIMS

The gastric cardia mucosa is a narrow band of tissue between the oesophagus and the stomach. The physiological role of this tissue is unknown. This study examined the presence and characteristics of neuroendocrine cells at this site.

METHODS

Biopsy samples were obtained from across normal appearing squamocolumnar junctions. The cardiac mucosa was defined as the presence of special type mucosa composed of mucous secreting glands in the immediate vicinity of oesophageal squamous epithelium. Biopsy specimens were stained with haematoxylin and eosin, alcian blue (pH 2.5) periodic acid Schiff, and modified Giemsa. The chromogranin A and Fontana-Masson stains were used to identify neuroendocrine cells, which were also stained immunohistochemically for gastrin, serotonin, glucagon, pancreatic polypeptide, somatostatin, and vasoactive intestinal peptide.

RESULTS

Chromogranin positive cells were seen in 18 cases with adequate biopsy specimens from the gastric cardia mucosa. These cells were all serotonin positive, but stains for other peptide hormones remained negative. Serotonin positive cells were detected only at the base of foveolae at the periphery of mucous secreting cardiac glands, giving a microscopic appearance resembling that of endocrine cells at the gastric antrum. The presence and numbers of serotonin positive cells did not correlate with chronic inflammation or intestinal metaplasia of the cardiac mucosa. These cells were seen both in Helicobacter pylori positive and negative patients.

CONCLUSIONS

Serotonin positive cells appear to be the sole neuroendocrine cell type at the gastric cardia mucosa. These cells may have a role in regulating the physiology of the gastric cardia mucosa and the lower oesophageal sphincter.

Histopathology of the gastroesophageal junction: a study on 36 operation specimens

The entire gastroesophageal junction of 36 patients who had been operated for squamous cell carcinoma of the upper or middle esophagus was examined. Hematoxylin and eosin-stained slides were evaluated by two pathologists for the following histologic details: minimal and maximal length of cardiac mucosa (CM) and oxyntocardiac mucosa (OCM, mixture of cardiac and fundic glands), degree of inflammation in CM and OCM, and presence of intestinal metaplasia or pancreatic metaplasia. Sections of gastric corpus mucosa were evaluated for the presence of gastritis and infection; sections of esophageal squamous epithelium were evaluated for the presence of reflux esophagitis. CM was present in the entire circumference of the gastroesophageal junction in 20 cases, in parts of the circumference in 15 cases, and entirely absent in one case. The maximal length per case ranged between 1 and 15 mm (median 5 mm). OCM was circumferentially present in 22 cases and partially present in 14 cases. The maximal length ranged between 2 and 24 mm (median 7 mm). Locations of CM/OCM over submucosal esophageal glands or squamous epithelium-lined ducts, both indicating a location in the esophagus, were found in eight cases (22%) and in four cases (11%), respectively. In 18 cases (50%) intestinal metaplasia was present in CM/OCM; pancreatic metaplasia was found in 22 cases (61%). A statistically not significant trend for increase of minimal length of CM, OCM, and the sum of both was found in the presence of gastroesophageal reflux disease. Neither the presence of intestinal metaplasia nor of pancreatic metaplasia in CM/OCM was correlated with gastroesophageal reflux disease. In conclusion, the high variability in length, the frequent occurrence of intestinal metaplasia and pancreatic metaplasia, and the frequent extension into the esophagus suggest that CM/OCM is a dynamic structure that probably mirrors the influence of underlying gastroesophageal diseases. Because of the short length and incomplete circumferential extension of CM/OCM, future endoscopic-bioptic investigations will probably have to be based on more extensive sampling of the gastroesophageal junction.

Morphology of the cardia and significance of carditis in pediatric patients

The morphology of the gastric cardia in children and the significance of inflammation in this region are unknown. Some investigators propose that the cardia is comprised of mucous glands at birth, whereas others suggest that mucous glands, when present, represent a metaplastic response to gastroesophageal reflux disease. The aim of this study was to evaluate the morphologic features of the cardia in a pediatric population and to determine the significance of inflammation in this region by correlating the pathologic features with clinical and endoscopic data. Routinely processed hematoxylin and eosin-stained mucosal biopsies of the cardia from 74 pediatric patients (age range 0.1-18 years; male/female ratio 0.76:1) without endoscopic evidence of Barrett's esophagus were examined for a variety of histologic features, such as the type of glandular epithelium (mucous, mixed mucous/oxyntic, oxyntic), and the amount and type of inflammation both within 1.0 mm and >1.0 mm from the squamocolumnar junction. The results were correlated with the patients' clinical symptoms and with other histologic features, such as esophagitis, gastritis, Helicobacter pylori, and the presence of goblet cells. Our results show that either pure mucous glands (81%) or mixed mucous/oxyntic-type glands (19%) were present within 1 mm of the squamocolumnar junction in all of the patients (100%) in this study. Patients with mixed mucous/oxyntic glands located <1 mm from the squamocolumnar junction were more likely to have goblet cells than were patients with mucous glands alone, but they did not differ with respect to any other feature, including patient age. However, both active esophagitis and increased inflammation in the cardia correlated positively with a longer length of pure mucous glands in the gastroesophageal junction region. Of the cases with inflammation (carditis), eosinophils correlated with the presence of active esophagitis (a histologic manifestation of gastroesophageal reflux disease), whereas increased lymphocytes correlated with chronic H. pylori gastritis. In summary, a small amount of pure mucous-type glands is present in the cardia in most pediatric patients, a finding that supports a congenital origin for this type of epithelium. However, our finding of an association between length of mucosa occupied by pure mucous glands and active esophagitis suggests that injury and repair related to gastroesophageal reflux disease may contribute to expansion of the zone occupied by cardia-type mucous glands.

Utilization of cytokeratins 7 and 20 does not differentiate between Barrett's esophagus and gastric cardiac intestinal metaplasia

Long segment Barrett's esophagus (LSBE) is a recognized risk factor for the development of esophageal dysplasia and carcinoma. However, the risk of dysplasia arising within intestinal metaplasia below a normal-appearing Z-line (i.e., in native cardiac mucosa) is unknown. Regular endoscopic surveillance is required in patients with LSBE and is frequently performed in short segment BE (SSBE), but the need for surveillance in cardiac intestinal metaplasia (CIM) is unknown. Unfortunately IM arising in SSBE and immediately below a normal Z-line can be indistinguishable histologically on H&E stains. Previous reports suggest that the appearance of superficial CK20 immunohistochemical staining accompanied by intermediate and deep CK7 positivity is characteristic of BE, whereas CIM specimens show superficial and deep CK20 positivity and weak to absent CK7 staining. We hypothesized that CK7/20 immunostaining of metaplastic biopsies from the esophagus and stomach would allow complete differentiation of these two entities when correlated with the endoscopic appearance. We undertook an evaluation of gastric and esophageal specimens to determine whether these characteristics were valid. Cases of both BE (long and short segment) and CIM, as well as cases of gastric cardiac biopsies lacking IM, were evaluated for CK7 and CK20 and correlated with the endoscopic appearance. We observed that, although the "Barrett's" pattern of CK7/20 was maintained for many cases of BE, the sensitivity and specificity were only moderate (65% and 56%, respectively). The pattern of staining for the CIM was variable, i.e., some cases showed a CK7/20 Barrett's pattern despite a normal appearance at endoscopy. The differences between this and previous studies may be due to inaccurate visualization of SSBE on endoscopy, the development of very early SSBE cases, inter-observer variability, fixation differences, or antibody differences. Whatever the cause of the differences, if results between laboratories are not comparable, CK7/20 immunostaining cannot be used to differentiate reliably between IM present in biopsy specimens taken from above versus below the Z-line. However, further studies should be performed to determine whether the presence or absence of a Barrett's pattern of CK7/20 immunostaining could predict progression to dysplasia or carcinoma.

Metaplastic columnar mucosa in the cervical esophagus after esophagectomy

OBJECTIVE

To evaluate the pathogenesis of metaplastic processes within the esophagus using a human model in which the exact duration of reflux was known.

SUMMARY BACKGROUND DATA

The pathogenesis of Barrett's esophagus (BE) is incompletely understood. Patients undergoing esophagectomy and gastric tube reconstruction represent a good model for studying the pathophysiology of columnar cell metaplasia of the human esophagus because the cervical esophagus is rarely or never exposed to gastric contents before the surgical procedure.

METHODS

Thirty-two patients underwent manometry, simultaneous 24-hour pH and bilirubin monitoring, and endoscopy with biopsy 3 to 10.4 years after esophagectomy. The presence of columnar mucosa in the cervical esophagus was confirmed on histologic examination. The findings on endoscopy and histology were related to clinical data and the results of pH and bilirubin monitoring 1 cm proximal to the esophagogastrostomy.

RESULTS

Fifteen (46.9%) of the 32 patients had metaplastic columnar mucosa within their cervical esophagus. Metaplasia was significantly more common in patients with a preoperative diagnosis of BE. The length of metaplastic mucosa correlated significantly with the degree of esophageal acid exposure, but the presence of abnormal bilirubin exposure was unrelated to the presence of metaplasia. The prevalence of metaplasia did not change with increasing time. Intestinal metaplasia was found within the columnar-lined segment in three patients 8.5, 9.5, and 10.4 years after esophagectomy. All patients with intestinal metaplasia had abnormal exposure of both acid and bilirubin, but the presence of combined reflux was not significantly higher in these patients compared with patients with nonintestinalized segments of columnar mucosa.

CONCLUSIONS

Esophageal columnar metaplasia is a common complication after gastric pull-up esophagectomy. Metaplasia is more likely to develop in patients with previous BE than other patients. Metaplasia develops in response to squamous epithelial injury in predisposed individuals.

Detection of Barrett's epithelium by acoustic microscopy

Barrett's esophagus is associated with increased risk of adenocarcinoma of the gastroesophageal junctional region. The presence of goblet cells (intestinal metaplasia) in columnar cell-lined esophageal mucosa defines Barrett's change. The diagnosis of Barrett's esophagus is based on the presence of intestinal metaplasia in a biopsy from an endoscopically visualized abnormal columnar epithelium. In this pilot study, acoustic microscopy was used to identify the mucosal structure of 10 distal esophageal biopsies. Sections cut at 5 microm of archival paraffin blocks on glass slides were used for this study. Acoustic microscopy permitted the identification of low- and high-power images of epithelial architecture and cellular detail, including Barrett's epithelium. This modality of visualization has the potential to detect lesions such as Barrett's metaplasia, low- and high-grade dysplasia and early carcinoma. If it can be applied to in vivo endoscopy, acoustic microscopy has the potential to increase the accuracy of the diagnosis of Barrett's esophagus, dysplasia and malignancy by providing a method of accurately directing biopsies at endoscopy.

Helicobacter pylori infection, not gastroesophageal reflux, is the major cause of inflammation and intestinal metaplasia of gastric cardiac mucosa

OBJECTIVE

The etiology of inflammation below the normal Z-line is an area of intense debate. Some suggest this is the earliest change of chronic gastroesophageal reflux disease (GERD), whereas others indict Helicobacter pylori (H. pylori) as the main cause. The aim of this study was to evaluate the relationship among inflammation of gastric cardiac mucosa (carditis), H. pylori infection, and intestinal metaplasia in patients with GERD and Barrett's esophagus compared with age-matched controls.

METHODS

Patients with GERD and Barrett's esophagus were compared with controls undergoing endoscopy for a variety of other conditions. Endoscopic biopsy specimens from the gastric cardia (obtained on retroflexed view), fundus, and antrum were evaluated for inflammation, H. pylori infection, and intestinal metaplasia.

RESULTS

The prevalence of H. pylori infection did not significantly differ among the study populations: controls (42%), GERD (33%), and Barrett's esophagus (27%) (p = 0.20). However, the prevalence of carditis significantly decreased from the control group (30%) to those with GERD (23%) and Barrett's esophagus (11%) (p = 0.03). Overall, 42 of 51 (82%) patients with carditis had H. pylori; all had pangastritis. The prevalence of cardia intestinal metaplasia also significantly decreased from the control group (15%) to those with GERD (4%) and Barrett's esophagus (0%) (p = 0.003). Of 13 patients with cardia intestinal metaplasia, 12 had carditis, 10 had H. pylori infection, and seven had intestinal metaplasia elsewhere in the stomach.

CONCLUSIONS

Inflammation of gastric cardiac mucosa decreases in prevalence from controls to patients with GERD and Barrett's esophagus and correlates strongly with H. pylori infection. Cardia intestinal metaplasia is associated with H. pylori-related cardiac inflammation and intestinal metaplasia elsewhere in the stomach.

Columnar-lined esophagus. Definitions

Recognition of a columnar-lined esophagus requires precise criteria by which to delimit the esophagus and the stomach. Endoscopically recognizable landmarks such as the squamocolumnar junction (SCJ or Z-line) can be used to identify structures at the gastroesophageal junction. Once the SCJ is located proximal to the gastroesophageal junction, a columnar-lined segment of esophagus is visible. If biopsy specimens from the columnar-lined segment show specialized intestinal metaplasia, then the patient has Barrett's esophagus (BE), and the extent of the columnar lining determines if it is short- or long-segment BE.

Intestinal metaplasia of the esophagus or esophagogastric junction: evidence of distinct clinical, pathologic, and histochemical staining features

Our purpose was to evaluate the clinical, histologic, and histochemical staining characteristics of intestinal metaplasia (IM) at an endoscopically normal-appearing esophagogastric junction (IM-EGJ) compared with IM in a columnar-lined esophagus (IM-CLE). A prospective study included 253 patients referred for elective upper gastrointestinal endoscopy. Biopsy specimens were obtained from 2 cm above and immediately distal to the squamocolumnar junction, the gastric corpus, and the antrum. Any red mucosa above the EGJ was sampled. IM-CLE (prevalence, 5.5%) typically occurred in white male smokers with a long history of reflux symptoms. IM-EGJ (prevalence, 9.1%) was associated with corpus and antrum gastritis and with IM at these sites. IM-CLE usually (13/14 [93%]) was the incomplete type IM, whereas only 12 (52%) of 23 patients in the IM-EGJ group had incomplete IM. IM-EGJ and IM-CLE should be considered as separate entities. Further research is needed to evaluate whether neoplastic progression of IM-EGJ is related to its mucin profile.

Prospective evaluation of multilayered epithelium in Barrett's esophagus

OBJECTIVE

We recently identified a distinctive type of multilayered epithelium in two patients with Barrett's esophagus, which shows morphological characteristics of both squamous and columnar epithelium. This study was performed to prospectively evaluate the prevalence of multilayered epithelium in patients with Barrett's esophagus.

METHODS

Mucosal biopsies were obtained from the squamocolumnar junction (Z-line) of 58 patients with endoscopic evidence of esophageal columnar epithelium and from the gastroesophageal junction in 21 patients without endoscopic evidence of esophageal columnar epithelium. Specimens were evaluated for the presence of multilayered epithelium and goblet cells.

RESULTS

Twenty-four of 58 (41%) of the patients with endoscopic evidence of esophageal columnar epithelium had multilayered epithelium compared with only one of 21 patients (5%) in the control group (p = 0.005). Of the 58 patients in the study group, 43 had goblet cell metaplasia and 15 did not (p < 0.001). Only patients with goblet cell metaplasia had multilayered epithelium. Shorter lengths of columnar epithelium were noted in the 24 patients with goblet cells and multilayered epithelium compared with the 19 patients with goblet cells and no multilayered epithelium (p < 0.05).

CONCLUSIONS

Multilayered epithelium is strongly associated with goblet cell metaplasia in patients with endoscopic evidence of esophageal columnar epithelium. These data support the hypothesis that multilayered epithelium may represent a transitional stage in the development of Barrett's esophagus.

Distribution and significance of epithelial types in columnar-lined esophagus

An abnormal columnar-lined esophagus (CLE) is characterized by the presence of cardiac mucosa (CM) oxynto-cardiac mucosa (OCM), and intestinal metaplastic epithelium (IM) between gastric oxyntic mucosa and esophageal squamous epithelium. Thirty-two patients with CLE measuring 2-16 cm long had 5-37 biopsies per patient that showed CM, OCM, or IM for a total of 424 biopsies. Detailed mapping of the distribution of epithelial types within the CLE showed a distinct zonation of epithelial types; CM was present throughout the CLE, whereas OCM and IM tended to occur in the distal and proximal part of the CLE, respectively. All 32 patients (64 of 68 biopsies) showed IM at the most proximal level, compared with 22 of 32 patients (40 of 102 biopsies) in the most distal level biopsies. The density of goblet cells was highest in the most proximal level. The differences in prevalence and density of goblet cells between most proximal and most distal level biopsies were highly significant. These data suggest that for a given number of biopsies within the CLE, the likelihood of finding IM is greatest when the biopsies are concentrated in the most proximal area of the CLE. We suggest that glandular transformation of squamous epithelium results in CM. which evolves into OCM and IM by development of specialized parietal cells and goblet cells, respectively. The severity and nature of reflux cause these epithelial transformations in a constant and predictable manner. Recognition of these changes permits the development of morphologic definitions of reflux disease and the characterization of the sequence of epithelial changes that represent the reflux-adenocarcinoma sequence.

Timely topic: Premalignant lesions associated with adenocarcinoma of the upper gastrointestinal tract

The changing incidence of adenocarcinomas, particularly in the oesophagus and gastric cardia, has led to the rapid expansion of screening programmes aimed at detecting the precursor lesion of dysplasia before adenocarcinoma develops. The pathologist now has an important role in first diagnosing patients at risk for developing dysplasia, and then correctly classifying dysplasia when it occurs. Barrett's oesophagus has had different diagnostic criteria in previous years but is currently diagnosed by the presence of intestinal metaplasia of any length in the true oesophagus. Intestinal metaplasia confined only to the gastro-oesophageal junction or cardia is of uncertain significance but is probably common, with less risk of progressing to dysplasia or malignancy. In the stomach, patients with autoimmune atrophic gastritis and Helicobacter-associated multifocal atrophic gastritis have an increased risk of adenocarcinoma, but screening protocols are not well-developed compared with those used for Barrett's oesophagus. Dysplasia of glandular epithelium can be classified using well-described criteria. Low grade dysplasia is the most common type and regresses or remains stable in the majority of patients. High grade dysplasia is more ominous clinically, with a propensity to coexist with or progress to adenocarcinoma.

Phenotypic characteristics of a distinctive multilayered epithelium suggests that it is a precursor in the development of Barrett's esophagus

A distinctive type of multilayered epithelium (ME) has been described at the neo-squamocolumnar junction and within columnar mucosa in patients with Barrett's esophagus (BE). This epithelium has morphologic and ultrastructural features of both squamous and columnar epithelium. Multilayered epithelium may represent an early or intermediate stage of columnar metaplasia; therefore, we performed this study to determine the morphologic and biologic characteristics of this epithelium and to gain insight into its derivation. Esophageal mucosal biopsies containing ME from 17 patients with BE were evaluated morphologically, stained with a variety of mucin histochemical stains; and also immunostained with antibodies against cytokeratins (CK) 13 (squamous epithelium marker); 14 (basal squamous epithelium marker) 7, 8/18, 19, and 20 (columnar epithelium markers), MIB-1 (proliferation marker); villin (intestinal brush border protein); and TGFalpha, EGFR, pS2, and hSP (enteric proliferation/differentiation regulatory peptides). The results were compared with normal esophageal squamous epithelium, normal gastric cardia epithelium, specialized-type intestinal epithelium (BE), and esophageal mucosal and submucosal gland duct epithelium. Multilayered epithelium expressed a pattern of mucin production (neutral mucin, sialomucin, and sulfomucin in 88%, 100%, and 71% of cases, respectively) and cytokeratin expression (CK 13 and 19 in the basal "squamoid" cells, CK 7, 8/18, 19, and 20 in the superficial "columnar" cells) similar to that of columnar epithelium in BE, and showed a high capacity for cellular proliferation (Ki-67-positive in 88% of cases) and differentiation (TGFalpha, EGFR, pS2 and villin-positive in 100%, 100%, 93%, and 66% of cases, respectively). The mucosal gland duct epithelium showed a similar phenotypic pattern and, in one case, was seen to give rise to ME at the surface of the mucosa. These data provide evidence in support of the hypothesis that ME represents an early or intermediate stage in the development of esophageal columnar metaplasia (BE). The mucosal gland duct epithelium may contain progenitor cells that can give rise to ME.

Carditis: a manifestation of gastroesophageal reflux disease

This series consists of 141 patients in whom cardiac mucosa (CM) was present in biopsy samples from the gastroesophageal junctional region. Inflammation of CM, irrespective of its exact anatomic location, was defined as carditis and classified as acute or chronic based on the number of inflammatory cells present. In all cases, CM showed significant chronic inflammation. One hundred and eleven (79%) of the 141 patients with carditis showed no evidence of gastritis in biopsy samples from the gastric antrum and body. Helicobacter pylori was present in 20 of 141 (14%) patients; of these, 17 had evidence of a pangastritis, with 15 of these patients also showing H. pylori in CM. Patients with severe chronic inflammation in CM had a significantly higher acid exposure of the lower esophagus as quantitated by a 24-hour pH test than those with mild chronic inflammation in CM. Acute inflammation was uncommon in CM; it was present in only 26 of 141 (18.4%) patients. There was no significant difference in acid exposure of the lower esophagus between patients with and without acute inflammation in CM. The presence of acute inflammation in CM was significantly associated with distal gastritis and H. pylori infection. Men with carditis had quantitatively higher acid exposure of the lower esophagus than did women with this disorder. This difference was greatest in men with severe inflammation in CM who had no evidence of distal gastritis. These findings provide evidence that chronic inflammation in CM is strongly associated with acid reflux and that H. pylori is not a significant etiologic factor in carditis. They also show that in patients with CM in whom H. pylori gastritis develops, the infection frequently spreads to involve CM, resulting in acute inflammation with neutrophils that is superimposed on the chronic inflammation already present.