Prevalence and significance of pancreatic acinar metaplasia at the gastroesophageal junction

Gastric development of pancreatic acinar cell metaplasia after Vonoprazan therapy in rats

BACKGROUND

Vonoprazan is a new acid-suppressing drug that received FDA approval in 2022. It reversibly inhibits gastric acid secretion by competing with the potassium ions on the luminal surface of the parietal cells (potassium-competitive acid blockers or P-CABs). Vonoprazan has been on the market for a short time and there are many clinical trials to support its clinical application. However, medical experience and comprehensive clinical data is still limited, especially on how and if, gastric histology is altered due to therapy.

METHODS

A 12-week experiment trial with 30 Wistar rats was to assess the presence of gastrointestinal morphologic abnormalities upon administration of omeprazole and vonoprazan. At six weeks of age, rats were randomly assigned to one of 5 groups: (1) saline as negative control group, (2) oral omeprazole (40 mg/kg), as positive control group, (3) oral omeprazole (40 mg/kg) for 4 weeks, proceeded by 8 weeks off omeprazole, (4) oral vonoprazan (4 mg/kg), as positive control group, and (5) oral vonoprazan (4 mg/kg) for 4 weeks, proceeded by 8 weeks off vonoprazan.

RESULTS

We identified non-inflammatory alterations characterized by parietal (oxyntic) cell loss and chief (zymogen) cell hyperplasia and replacement by pancreatic acinar cell metaplasia (PACM). No significant abnormalities were identified in any other tissues in the hepatobiliary and gastrointestinal tracts.

CONCLUSION

PACM has been reported in gastric mucosa, at the esophagogastric junction, at the distal esophagus, and in Barrett esophagus. However, the pathogenesis of this entity is still unclear. Whereas some authors have suggested that PACM is an acquired process others have raised the possibility of PACM being congenital in nature. Our results suggest that the duration of vonoprazan administration at a dose of 4 mg/kg plays an important role in the development of PACM.

Pancreatic acinar metaplasia at the gastroesophageal junction is associated with protective effect against intestinal metaplasia in patients with gastroesophageal reflux disease

Anecdotal evidence suggests that pancreatic acinar metaplasia (PAM) and intestinal metaplasia (IM) overlap infrequently at the gastroesophageal junction/distal esophagus (GEJ/DE). The goal of this study was to evaluate the significance of PAM at GEJ/DE in relation to IM in patients with gastroesophageal reflux disease (GERD). Group 1 comprised 230 consecutive patients with GEJ/DE biopsies (80.6% with GERD symptoms). Group 2 comprised 151 patients with established GERD and GEJ/DE biopsies taken before Nissen fundoplication. Group 3 comprised 540 consecutive patients used for a follow-up study of PAM. PAM was present in 15.7%-15.9% and IM in 24.8%-31.1% of patients in groups 1 and 2, respectively. PAM-IM overlap was present in 2.2%-3.3%, respectively. Patients with PAM were, on average, 6-12 years younger than patients with IM, and were predominantly female (72.2%-75%), in contrast to patients with IM (47.3%-32%). In the unadjusted logistic regression model, patients with PAM were 69%-65% less likely to also have IM, as compared to patients without PAM. In the fully adjusted model, patients with PAM were 35%-61% less likely to also have IM, although the P-value was not significant. Follow-up analysis of patients with PAM from group 3 (n = 28) demonstrated the prevalence of IM and PAM in subsequent biopsies at 7.1% and 60.7%, respectively. No cases showed PAM-IM overlap on follow-up. The data suggests that PAM at the GEJ/DE is associated with protective effect against IM and thus could be useful as a marker of decreased susceptibility to IM.

Development of Pancreatic Acinar Cell Metaplasia During Gastric Repair in a Rat Duodenal Contents Reflux Model

BACKGROUND

We previously reported the development of pancreatic acinar cell metaplasia (PACM) in the glandular stomach of a duodenal contents reflux model (reflux model).

AIMS

We aimed to investigate the characteristics and histogenesis of PACM using a reflux model.

METHODS

A reflux model was created using 8-week-old male Wistar rats, which were killed up to 30 weeks postoperatively. Histological examination was performed to analyze the glandular stomach-jejunal anastomosis. Furthermore, electron microscopic images of PACM samples were compared with pancreatic and gastric glands removed from rats that had not undergone surgery. Immunostaining for α-amylase, HIK1083, TFF2, and Ki-67 was performed, and double fluorescent staining was carried out using antibodies against α-amylase and HIK1083, or α-amylase and TFF2.

RESULTS

In all reflux model rats, PACM was observed proximal to the glandular stomach-jejunal anastomosis, surrounded by pseudopyloric metaplasia. The number of chief cells was decreased in the deep part of the gland, where PACM occurred. Electron microscopy showed that PACM cells had greater numbers of rough endoplasmic reticulum tubules than chief cells, and exhibited pancreatic acinar cell morphology. Upon immunochemical staining, the regenerative foveolar epithelium and part of the pseudopyloric glands stained strongly positive for TFF2, whereas PACM cells were only weakly positive. Double fluorescent staining identified early lesions of PACM in the neck, which were double positive for α-amylase and TFF2, but negative for HIK1083.

CONCLUSIONS

PACM could be induced by duodenal contents reflux. PACM originates from stem cells located in the neck of oxyntic glands during gastric mucosal regeneration.

Pancreatic Acinar Metaplasia in Distal Esophageal Biopsies Is Associated With Chronic Nonsteroidal Anti-inflammatory Drug Use

CONTEXT.—

The cause of pancreatic acinar metaplasia (PAM) at the distal esophagus/esophagogastric junction is still controversial. Whereas some authors believe it is congenital, others believe it is acquired because of inflammation of the gastric cardia, and more recently it was proposed to be due to chronic proton pump inhibitor use based on a study in rats.

OBJECTIVE.—

To determine whether there is correlation between chronic proton pump inhibitor use and PAM in humans. We also investigated the correlation between several clinical and pathologic factors and PAM.

DESIGN.—

Four hundred forty-four consecutive biopsies from the distal esophagus/esophagogastric junction were reviewed for the presence of PAM, which was then correlated with several clinical and pathologic findings.

RESULTS.—

Pancreatic acinar metaplasia was found in 71 patients (16%). Pancreatic acinar metaplasia was significantly associated with patient age younger than 51 years ( P < .001), chronic carditis ( P = .01), and chronic proton pump inhibitor use ( P = .008). Surprisingly, we also found significant association between PAM and chronic nonsteroidal anti-inflammatory drug use ( P < .001). These associations, including that with chronic nonsteroidal anti-inflammatory drug use, remained significant in multivariate analysis.

CONCLUSIONS.—

Our findings confirm the previous reports of significant association between PAM and chronic carditis and the findings from animal studies of association with chronic proton pump inhibitor use. The strong association with chronic nonsteroidal anti-inflammatory drug use has not been previously reported and warrants further studies.

Cardiac mucosa at the gastroesophageal junction: An Eastern perspective

AIM: To investigate the nature and origin of cardiac mucosa (CM).

METHODS: Biopsy samples from sixty-one individuals were included in this study. The specimens were taken “at”, “just below”, or “just above” the gastroesophageal junction, including the histologic squamocolumnar junction. Clinical data were obtained by reviewing electronic medical records for each patient. Patients with a history of stomach adenoma or carcinoma and esophageal carcinoma were excluded, and cases that were endoscopically suspicious of Barrett’s esophagus or a polyp were also ruled out. Histologic and endoscopic reviews were performed blinded to the patient’s clinical data. Histologic evaluation was conducted by two pathologists, and endoscopic review was performed by a endoscopist with wide experience in the field. Histologically, the columnar epithelium of squamocolumnar junction, presence and severity of acute and chronic inflammation, atrophy, intestinal metaplasia, and presence of carditis were evaluated. Endoscopically, reflux esophagitis was evaluated by Los Angeles (LA) classification, hiatal hernias were classified by Hill grade, and gastroesophageal flap valves were assessed.

RESULTS: Fifty-nine of the 61 (96.7%) patients were Korean; 65.6% (40/61) of the patients underwent endoscopy according to the schedule of the National Health Insurance Program as a screening inspection. Of these, only 20.0% (8/40) of cases had reflux symptoms. CM was present in 41/61 (67.2%) individuals, and its presence was associated with older age compared to oxyntocardiac mucosa/oxyntic mucosa (60.59 ± 2.02 years vs 51.55 ± 3.35 years; P = 0.018). The presence of CM was associated with endoscopic diagnosis of esophagitis according to the LA classification (P = 0.022). CM was associated with mononuclear cell infiltration and neutrophilic infiltration, which were statistically significant (P = 0.001, and P = 0.004, respectively). The inflammation of CM, “carditis”, showed a statistically significant association with endoscopic diagnosis of reflux esophagitis according to the LA classification (P = 0.008).

CONCLUSION: CM at the gastroesophageal junction is a common histologic finding in biopsy specimens, though not always present, and associated with gastroesophageal reflux disease and carditis severity.

Pancreatic acinar cells--a normal finding at the gastroesophageal junction? Data from a prospective Central European multicenter study

Pancreatic acinar cells are a well-recognized finding at the gastroesophageal junction, but their histogenesis and biological significance are unclear. From the prospective Central European multicenter histoGERD trial, we recruited 1,071 individuals undergoing gastroscopy for various non-selected reasons. Biopsy material was systematically sampled from the gastroesophageal junction and from the stomach. The study aimed to assess the prevalence of pancreatic acinar cells and to relate their presence to various histologic and clinical features. Overall, pancreatic acinar cells were observed in 184 (17.2%) participants. Individuals diagnosed with pancreatic acinar cells were slightly younger than those without (median 50 vs. 53 years; p = 0.009). There was no association with patients' symptoms and/or complaints or with an endoscopic diagnosis of esophagitis or Barrett's esophagus. Regarding histology, pancreatic acinar cells were not associated with features of the squamous epithelium indicating reflux disease, such as basal cell hyperplasia, papillary elongation, dilation of intercellular spaces, and inflammatory cell number, but were associated with the presence of cardiac mucosa (p < 0.001), oxyntocardiac mucosa (p < 0.001), and intestinal metaplasia (p = 0.038), respectively. No association with Helicobacter pylori infection or diagnosis of gastritis was noted. In conclusion, pancreatic acinar cells are a common finding at the gastroesophageal junction, and no association with either reflux disease (histologically or endoscopically) or diagnosis of gastritis was observed. These data suggest a congenital rather than an acquired (metaplastic) origin of pancreatic acinar cells at the gastroesophageal junction. This questions the term "pancreatic acinar metaplasia" which is currently widely used for their diagnosis.

The prevalence of pancreatic acinar differentiation in gastric adenocarcinoma: report of a case and immunohistochemical study of 111 additional cases

Although pancreatic acinar metaplasia in the gastric mucosa is well recognized in chronic gastritis, gastric carcinoma with acinar differentiation is very rare. We encountered a case of gastric adenocarcinoma with prominent histologic and immunohistochemical features of pancreatic acinar differentiation in the absence of identifiable heterotopic pancreatic tissue. Distinct glandular and diffuse patterns of adenocarcinoma were also present, and there was focal mucin production. The tumor strongly expressed pancreatic exocrine enzymes trypsin and chymotrypsin, and focal neuroendocrine staining was also present. To investigate the prevalence of acinar differentiation in histologically typical gastric cancers, we performed immunohistochemical staining for trypsin and chymotrypsin on a tissue microarray containing 111 conventional gastric adenocarcinomas (60 intestinal, 28 mixed, 22 diffuse type, and 1 undifferentiated). No obvious morphologic evidence of acinar differentiation was identified in any of the 111 cases. Although some cases showed equivocal staining for at least 1 pancreatic exocrine enzyme on the initial tissue microarray sections, repeat immunohistochemical staining on representative whole-tissue sections failed to reproduce positive staining. Thus, acinar differentiation is rare in gastric adenocarcinomas, other than in histologically unusual cases such as the one we report, and in others from the literature, which are reviewed.

Pancreatic acinar-like adenocarcinoma of the proximal stomach invading the esophagus

The aim of this study was to systematically investigate clinicopathologic features of the recently described pancreatic acinar-like adenocarcinoma of the proximal stomach invading the esophagus (n = 43). Patient median age was 66 years (range, 51-90 years). The male-to-female ratio was 7.6. Grossly, pancreatic acinar-like adenocarcinoma tumors were nonencapsulated with the median size of 5.5 cm (range, 2-10.5). Bormann's types 1 to 4 tumors were in 7%, 9%, 67%, and 16% cases, respectively. Frank necrosis, hemorrhage, and cysts were rare or absent. Lymphovascular (81%), perineural (74%), and lymph node (81%) invasions were more common in the pancreatic acinar-like adenocarcinoma than in the non-pancreatic acinar-like adenocarcinoma (n = 94) groups. Microscopically, pancreatic acinar-like adenocarcinoma tumors showed acinar (78%), micropapillary (12%), microcystic, solid, trabecular, and mixed neuroendocrine or signet ring (33%) patterns of growth. No adenosquamous differentiation was noted in the pancreatic acinar-like adenocarcinoma group. Nuclei were round to oval with thickened nuclear membrane, stippled chromatin, and single prominent nucleoli. Mitotic figures were variable. The cytoplasm was moderate, eosinophilic, finely granular, and diffusely immunoreactive to the α1-chymotrypsin antibody in all cases to various degrees. Tumor stroma was nondesmoplastic, delicate, and fibrovascular. Pancreatic acinar-like adenocarcinoma tumors staged pI, pII, pIII, and pIV were in 2%, 21%, 70%, and 7% of cases, respectively. The median number of follow-up months after surgery was 29. The 2-year survival rate was 67%, lower than that (73%) in the non-pancreatic acinar-like adenocarcinoma group. A worse overall survival trend was found for patients in the pancreatic acinar-like adenocarcinoma than in non-pancreatic acinar-like adenocarcinoma groups, but the difference was not statistically significant. Age older than 75 years and overall pathology stage were independent risk factors.

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.

Pancreatic acinar metaplasia in the distal oesophagus and the gastric cardia: prevalence, predictors and relation to GORD

PURPOSE

The nature of pancreatic acinar metaplasia (PAM) in the gastro-oesophageal junction (GOJ) remains obscure. We aimed to estimate its prevalence and investigate into its risk factors in a population-based series of first-time endoscopy patients.

METHODS

We investigated consecutive patients, endoscoped for the first time, representing defined catchment area populations. Biopsies were taken immediately below the GOJ and from the distal oesophagus. Endoscopy room-based cross-sectional clinical data were supplemented with exposure data from 160 population controls. Associations, expressed as odds ratios (OR), were modelled with multivariable logistic regression. A subsample of 26 patients underwent oesophageal pH monitoring.

RESULTS

Among 644 patients (mean age 53 years, 43% men), PAM was found in 121 patients (19%), exclusively above the GOJ in 40 (6%), below GOJ in 67 (10%), and both above and below GOJ in 14 (2%). PAM exclusively above the GOJ and PAM exclusively below the GOJ were both borderline associated with age (2% increase in prevalence per year). PAM exclusively above the GOJ was significantly associated with female gender (OR 2.8, 95% CI 1.3-6.3) and presence of Helicobacter pylori immediately below the GOJ (OR 2.6, 95% CI 1.3-5.4). Out of 21 patients with Barrett's oesophagus (BO), 8 (38%) had PAM above the GOJ. The mean value for percentage time with oesophageal pH < 4.0 was 7.3% (95% CI 4.3-10.2%) among patients who had PAM above the GOJ (reference value 3.4%).

CONCLUSIONS

Pancreatic acinar metaplasia might be an age-dependent lesion, associated with H. pylori, female gender and gastro-oesophageal reflux if located above the GOJ.

Histology of metaplasia and dysplasia in Barrett's esophagus

The histologic diagnosis of Barrett's dysplasia requires the identification of intestinal metaplasia, which often presents a challenge due to sampling error, observer variation, and difficulty in histologic interpretation. Particularly problematic is the separation of negative, indefinite, and low-grade dysplasia, the varied histological appearances of high-grade dysplasia, and the diagnosis of suboptimal biopsy material. This article seeks to aid in the histological evaluation of metaplasia and dysplasia in Barrett's esophagus.

Pancreatic metaplasia in the gastro-achlorhydria in WTC-dfk rat, a potassium channel Kcnq1 mutant

The WTC-deafness Kyoto (dfk) rat is a new mutant characterized by deafness and abnormal, imbalanced behavior. WTC-dfk rats carry an intragenic deletion at the Kcnq1 gene; KCNQ1 plays an important role in K(+) homeostasis, and the mutation of Kcnq1 causes a cardiac long QT syndrome in humans. Here, we studied stomach lesions in these WTC-dfk rats. The most characteristic pathologic feature in the stomach was the appearance of hypertrophic gastric glands in the stomach body. The hypertrophic cells had many eosinophilic granules in their cytoplasm, and these granules were stained red with Azan stain; stained positively for trypsinogen, amylase, and chymotrypsin; and did not stain positively for pepsinogen when using immunohistochemical analysis. These staining results suggested a metaplasia toward a pancreatic acinar cells. Extensive fibrosis was found in the bottom part of the mucosa of 34-week-old WTC-dfk rats, suggesting a progression of stomach lesions with aging. Although cells that were positive for proliferating cell nuclear antigen were restricted in the area of the glandular neck in WTC control rats, positive cells in WTC-dfk rats were scattered throughout the mucosa. The parietal cells in WTC-dfk rats were negative for KCNQ1 immunohistochemical analysis. These findings indicate that a deficiency in rat Kcnq1 provokes an abnormal proliferation and differentiation of gastric glandular cells.

The histopathologic spectrum of carcinomas involving the gastroesophageal junction in the Chinese

Carcinomas involving the gastroesophageal junction are common in China. The histopathologic characteristics of these cancers have not been systematically investigated. Reported are 41 such resected cancers from Chinese patients (30 men, 11 women). Their mean age was 62 years. The mean tumor size was 4.4 cm (range, 2 to 9 cm), and 58% were poorly differentiated. An unusual spectrum of tumor differentiation was observed, including adenocarcinomas (83%), adenosquamous (32%), colloid (2%), signet-ring (10%), squamous (5%), oncocytic (7%), pancreatic acinar (12%), and neuroendocrine (5%) carcinomas. Cancers with multiple types of differentiation in the same tumor were identified in 37 cases (90%). The adjacent gastric cardiac mucosa showed hyperplasia, oncocytic, and pancreatic acinar metaplasia, and mild chronic inflammation. Dysplasia was uncommon (n = 6). Barrett esophagus was not identified. Carcinomas involving the gastroesophageal junction in the Chinese are morphologically distinct, heterogeneous, and may be of esophageal origin.

Composite Glandular and Endocrine Tumors of the Stomach With Pancreatic Acinar Differentiation

Composite tumors of the stomach consisting of mixed glandular and endocrine components are rare. We report 3 cases of composite glandular and endocrine tumors with pancreatic acinar differentiation in the stomach with their clinicopathologic findings. The patients' presenting symptoms were variable and included abdominal pain, gastrointestinal hemorrhage, and weight loss. One patient with abdominal pain also had an elevated serum lipase level, clinically mimicking acute pancreatitis. The histology of these tumors was similar. They showed admixture of well-differentiated endocrine components with acinar and glandular components. The glandular component consisted of columnar epithelial cells resembling gastric foveolar or intestinal goblet cells, consistent with a well-differentiated adenocarcinoma. A panel of histochemical and immunohistochemical stains was performed, which included PAS, Alcian blue, Mib1, CEA, cytokeratin 7, cytokeratin 20, Muc2, Muc5AC, chromogranin, synaptophysin, trypsin, chymotrypsin, lipase, insulin, gastrin, serotonin, and pancreatic polypeptide. While the immunoreactivity for cytokeratin 7, cytokeratin 20, Muc2, Muc5AC, and CEA was largely restricted to the glandular component, the endocrine and pancreatic acinar markers showed marked variability and overlap. All cases showed immunoreactivity for at least one of the exocrine pancreatic enzymes, and all expressed endocrine differentiation. Some degree of amphicrine differentiation was suggested in all cases. Two cases showed metastases in perigastric lymph nodes, which histologically resembled the primary tumor. In summary, these tumors represent another distinct type of composite glandular and endocrine gastric neoplasm with pancreatic acinar differentiation.

Prevalence of precancerous and other metaplasia in the distal oesophagus and gastro-oesophageal junction

OBJECTIVE

The epidemiology of Barrett's oesophagus (BO) is characterized by divergent results. The aim of this study was to estimate the prevalence of BO and intestinal metaplasia (IM) at the gastro-oesophageal junction (GOJ) in a population-based series of patients referred for first-time gastroscopy.

MATERIAL AND METHODS

Consecutive patients who underwent endoscopy for the first time at endoscopy units exclusively serving defined catchment areas were invited to take part in the study. Biopsies were taken immediately below the GOJ and from the distal oesophagus, and clinical data were recorded.

RESULTS

A total of 769 patients (mean age 53 years, 43% M) were examined. Overall IM prevalence was 14%. BO was noted in 4%. Overall, the prevalence of IM increased by 8% (95% CI 6-10%) per year of age. BO patients were predominately women (69%). Presence of cardia-type mucosa in the cardia increased with age from 25% among the youngest to 59% among the oldest patients. Pancreatic acinar metaplasia (PAM) was found in 18%.

CONCLUSIONS

While BO is not common among Swedish gastroscopy patients, IM and PAM are found in every 7th and 6th patient, respectively. Age-dependent increments in prevalence suggest that not only BO and IM, but also cardia-type mucosa are acquired and/or progressive lesions.

Fine-needle aspiration cytology findings from a case of pancreatic heterotopia at the gastroesophageal junction

Pancreatic heterotopia is a well-recognized entity occurring at a variety of sites in the gastrointestinal tract. However, only a handful of patients have been described with this abnormality at the gastroesophageal junction. Cytologic descriptions of pancreatic heterotopia in general are scant in the literature. We report the cytologic findings of ectopic pancreatic tissue at the gastroesophageal junction in a 41-year-old female, which was initially identified by endoscopic ultrasound and fine-needle aspiration. Cytologic examination of Papanicolaou-stained smears revealed clusters of benign-appearing ducts and small acini mixed with inflammatory cells. Hematoxylin and eosin staining of the Tru-Cut biopsy revealed benign pancreatic tissue. The patient underwent surgical resection due to symptoms related to inflammation of the heterotopic pancreatic tissue. The increasing use of endoscopic ultrasound and fine-needle aspiration for the diagnosis of gastrointestinal tumors makes the recognition of pseudoneoplastic lesions at unusual sites an important step in optimum patient management.

Ciliated Surface in the Esophagogastric Junction Zone

We have previously reported squamous metaplasia-like change at the esophagogastric junction (EGJ). In the present study, we examined these lesions histologically and by immunohistochemistry and electron microscopy. Samples of EGJ mucosa, 3 cm long and comprising 1.5-cm long portions of both columnar and squamous mucosa, were obtained from 43 esophagectomy resection specimens. Squamous metaplasia-like change was observed in 21 (49%) of the 43 cases. The squamous metaplasia-like change was generally positive with immunohistochemical stains for tubulin and cytokeratins (CKs) 4, 7, 8, 13, and 18, and was generally negative with stains for CKs 10, 14, and 20. This pattern of immunoreactivity is very similar to that of bronchial mucosa. Also, many cilia were detected at the apices of the cells by electron microscopy in 5 (31%) of the 16 cases that were able to be examined. Therefore, squamous metaplasia-like change at the EGJ has both a similar appearance and a similar immunohistochemical profile to respiratory bronchial epithelium. These findings may suggest that squamous metaplasia-like change at the EGJ is not a precursor of Barrett's mucosa but rather is a form of pseudostratified metaplasia.

Immunological and morphogenic basis of gastric mucosa atrophy and metaplasia

Chronic gastritis with gastric mucosa atrophy, intestinal metaplasia and endocrine cell hyperplasia are alterations with an increased risk for the development of gastric neoplasias. Immunological studies in autoimmune gastritis, in atrophic Helicobacter pylori gastritis and in studies with transgenic mice point to a central role of the parietal cell in the development of gastric mucosa atrophy. Destruction of gastric epithelial cells alone might not be sufficient for the loss of complete gastric glands. Gastric atrophy, endocrine cell hyperplasia and intestinal and pancreatic metaplasia can be regarded as the result of altered morphogenesis within the gastric mucosa. Impaired expression of the gastric morphogenic factor Sonic Hedgehog by parietal cells and increased expression of the transcriptional activators of intestinal and pancreatic differentiation, namely CDX2 and PDX1, seem to be crucial for the development of gastric atrophy and for intestinal, endocrine and pancreatic transdifferentiation processes. Altered expression of these morphogenic factors is partly caused by changes in the gastric milieu. Further studies concerning the normal and pathological morphogenesis of the gastric mucosa and related tissues might give new insight into the pathogenesis of gastric atrophy and metaplasia.

Inlet patch: prevalence, histologic type, and association with esophagitis, Barrett esophagus, and antritis

CONTEXT

Inlet patch is a congenital anomaly of the cervical esophagus consisting of gastric mucosa. Case reports have documented the histologic type and its associated complications.

OBJECTIVE

To report the prevalence and histologic types of inlet patch as well as its association with Barrett esophagus and Helicobacter pylori-associated gastritis.

DESIGN

We reviewed 1821 consecutive pathology reports from endoscopies of the upper gastrointestinal tract between 1995 and 2002 and identified 20 patients with inlet patch. The patients' ages ranged from 16 to 75 years (mean, 55 years). We examined biopsies from these patients of the cervical esophagus, distal esophagus, and antrum that had been stained with hematoxylin-eosin and the Steiner stain. Biopsies from the cervical esophagus composed of nonoxyntic gastric mucosa were also stained for gastrin-producing cells.

RESULTS

In our patient population, inlet patch occurred in 1.1% of all patients in whom an inlet patch had been searched for endoscopically and a biopsy performed. In the inlet patch, oxyntic mucosa was the most common histologic type (11/20), followed by cardiac mucosa (5/20). Four specimens of the inlet patch contained only foveolar epithelium and were therefore considered too superficial to be classified. Twelve of 20 biopsies of the inlet patch were inflamed, and 1 of them was associated with H pylori. Pancreatic acinar tissue was noted in 2 patients; no intestinal metaplasia was found. In the distal esophagus, 4 patients with inlet patch had distal esophagitis, 4 had Barrett esophagus, 5 had oxyntic mucosa, 3 had pancreatic acinar tissue (1 coexisting with oxyntic mucosa), and 5 presented with only unremarkable esophageal squamous mucosa. Antral gastritis was seen in 2 patients, 1 of them with H pylori. The same patient also had H pylori in the inlet patch.

CONCLUSION

Inlet patch occurred in about 1% of our study population. Oxyntic mucosa constituted the most common histologic type; inflammation was common. The H pylori infection of the inlet patch correlated with that of the antrum. None of the inlet patch biopsies showed intestinal metaplasia. Pancreatic acinar tissue occurred with similar frequency in the inlet patch and distal esophagus. Esophagitis was noted in 25% of the patients with inlet patch, and Barrett esophagus was noted in 20%.

Pancreatic acinar cell metaplasia in autoimmune gastritis

OBJECTIVE

To determine the frequency and significance of pancreatic acinar cells in the gastric oxyntic mucosa.

DESIGN

One hundred gastric oxyntic mucosal biopsy specimens from patients with chronic active gastritis (n = 30), multifocal atrophic gastritis (n = 15), autoimmune gastritis (n = 18), and normal gastric oxyntic mucosa (n = 37) were evaluated for the presence of pancreatic acinar cells. Formalin-fixed, paraffin-embedded tissues were stained with hematoxylin-eosin, and those positive for pancreatic acinar cells were immunostained with antibodies against trypsin and pancreatic amylase.

RESULTS

Eleven (11%) of 100 oxyntic mucosal tissue samples contained pancreatic acinar cells. These samples came from 9 of the 18 (50%) specimens of autoimmune gastritis, 1 of the 15 (6.6%) specimens of multifocal atrophic gastritis, and 1 of the 37 (2.7%) specimens of normal oxyntic mucosa. None of the samples with chronic active gastritis contained pancreatic acinar cells.

CONCLUSIONS

Pancreatic acinar cells were found in the oxyntic mucosa of patients with autoimmune gastritis significantly more frequently (P <.001) than in individuals with multifocal atrophic gastritis, normal oxyntic mucosa, or chronic active gastritis. Our study supports a metaplastic origin for pancreatic acinar cells in the oxyntic mucosa. Furthermore, detection of pancreatic acinar cells in the oxyntic mucosa of patients with gastritis strongly suggests an autoimmune pathogenesis.

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.

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.

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.

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.

Prevalence and pathogenesis of pancreatic acinar tissue at the gastroesophageal junction in children and young adults

BACKGROUND

Pancreatic acinar tissue (PAT) at the gastroesophageal junction (GEJ) has been reported in 3% of adults with Barrett esophagus (BE) and in 24% of healthy subjects. The pathogenesis of this ectopic tissue is controversial. Both an acquired metaplastic process in the setting of BE and a congenital abnormality have been suggested in adults.

OBJECTIVE

To clarify the origin of PAT at the GEJ.

METHODS

We reviewed material obtained from the GEJ in 69 children and young adults. Each specimen was evaluated by 3 levels stained with hematoxylin-eosin for the presence of PAT, BE, esophagitis, and gastritis. Selected cases were also examined with immunohistochemical stains for lipase, trypsin, and amylase.

RESULTS

In 16% of the study population, PAT was present at the GEJ and was not associated with BE. The prevalence of esophagitis and/or gastritis did not vary significantly between patients with and without PAT.

CONCLUSIONS

Our data suggest that PAT at the GEJ develops independently of inflammation and is, therefore, likely to be congenital.

The gastric cardia in gastro-oesophageal disease

BACKGROUND

There have been conflicting reports concerning the use of cardia biopsies in screening patients for gastro-oesophageal disease.

AIM

To define the histopathological changes in the gastric cardia of patients with and without gastro-oesophageal disease.

METHODS

Topographically mapped gastric biopsy specimens were obtained from patients with gastro-oesophageal disease and from controls. Biopsies were scored on a visual analogue scale of 0 to 5 for Helicobacter pylori, intestinal metaplasia, pancreatic metaplasia, foveolar hyperplasia, and active inflammation. The presence or absence of cardiac glands was recorded.

RESULTS

Sixty-five patients with gastro-oesophageal disease and 71 controls were examined. Intestinal metaplasia was present in cardia biopsies of 10 patients with gastro-oesophageal disease and 11 controls. Only two patients with gastro-oesophageal disease and intestinal metaplasia in the cardia had no evidence of exposure to H pylori. Intestinal metaplasia was not found in the cardia of those with long segment Barrett's oesophagus. Carditis was strongly associated with active H pylori infection (p = 0.000) and resolved after treatment of the infection. A negative association was present between gastro-oesophageal disease and the presence of cardiac glands in cardiac biopsies (p = 0.003). Pancreatic metaplasia was found in 15 of 65 and foveolar hyperplasia in 19 of 65 cases but neither was related to gastro-oesophageal disease.

CONCLUSION

Intestinal metaplasia in the cardia is uncommon in gastro-oesophageal disease in the absence of H pylori infection. With chronic H pylori infection the junction between the cardia and corpus expands in a cardia-corpal direction.

Intestinal and pancreatic metaplasia at the esophagogastric junction in patients without Barrett's esophagus

OBJECTIVES

A distinctive type of columnar epithelium with intestinal metaplasia is considered diagnostic for Barrett's esophagus. The neoplastic potential of pancreatic metaplasia at the esophagogastric junction is unknown. The aims of the present study were: 1) to characterize both forms of metaplasia at the esophagogastric junction, and to estimate their prevalence; 2) to investigate c-erbB-2 expression and K-ras mutations in pancreatic metaplasia; and 3) to study the relationship between metaplasia, inflammatory changes in the cardiac mucosa, and presence of H. pylori.

METHODS

A total of 76 esophagogastrectomy specimens of patients with a normally located squamocolumnar junction, were investigated immunohistochemically. K-ras mutations were evaluated using PCR.

RESULTS

Intestinal metaplasia in the cardia was found in 12% of patients: six complete-type, and three incomplete-type. Pancreatic metaplasia was demonstrated in 14% of patients, and neither c-erbB-2 expression nor K-ras mutations were found. Intestinal and pancreatic metaplasia were associated with mucosal inflammation. In contrast to generalized gastritis, isolated "carditis" was not associated with H. pylori infection.

CONCLUSIONS

When intestinal metaplasia occurs in a biopsy from the esophagogastric junction, it is not necessarily a marker for Barrett's esophagus. No indication was found that pancreatic metaplasia has neoplastic potential. Both forms of metaplasia reflect mucosal inflammation. Carditis may be a distinct inflammatory condition of the gastric mucosa that is not related to H. pylori infection.

Barrett's esophagus: the long and the short of it

Specialized intestinal epithelium occurs more frequently at the gastroesophageal junction than previously anticipated. It can occur either within tongues of mucosa (short segment Barrett's) or just beneath a normal z-line (intestinal metaplasia at the gastroesophageal junction). Whether the etiopathogenesis and the natural history of these two conditions are the same is as yet unclear. The role of gastroesophageal reflux disease (GERD), Helicobacter pylori, and inflammation at the gastroesophageal junction in the pathogenesis of short segment Barrett's and intestinal metaplasia at the gastroesophageal junction needs to be carefully documented. Intestinal metaplasia at the gastroesophageal junction, short segment Barrett's, and Barrett's may represent a continuum of the same disease process. Recent evidence suggests, however, that short segment Barrett's shares similar characteristics with Barrett's but may be distinct from intestinal metaplasia at the gastroesophageal junction. It is conceivable that short segment Barrett's may remain steady or even regress if and when the noxious influence wanes but, with continuing stimulation, short segment Barrett's may lengthen further to become what we observe to be Barrett's. If correct, endogenous or exogenous factors that induce progression need to be identified. Acid and bile reflux and H. pylori are possible candidates acting either singly or synergistically. Finally, the true neoplastic potential of short segment Barrett's needs clarification.

Pancreatic acinar cell clusters in pediatric gastric mucosa

Although clusters of pancreatic acinar cells (CPACs) have been reported in gastric mucosa of adults, they have not been described in children. We reviewed 283 pediatric gastric (239 antral and 44 corpus) mucosal biopsies during a 2-year period and detected CPACs in 10 antral biopsy samples. These biopsy samples were stained immunohistochemically for pancreatic exocrine markers (trypsin, chymotrypsin, alpha-amylase, and lipase) and a panel of regulatory substances (insulin, glucagon, somatostatin, pancreatic polypeptide, gastrin, and serotonin). Double immunostaining for colocalization of chromogranins and trypsin as well as mucin and trypsin also were performed on all cases. CPACs were seen in antral mucosa in a background of either normal or minimally inflamed mucosa, without any atrophy or metaplasia, and were positive for all pancreatic exocrine markers. Stray chromogranin-positive cells in the CPACs were also immunopositive for somatostatin, gastrin, or serotonin. All CPACs showed a few hybrid (amphicrine) cells that coexpressed both chromogranin and trypsin. In one case, ultrastructural examination showed such cells to contain both zymogen and neurosecretory granules. Although the presence of CPACs exclusively in the antrum is most likely the result of a sampling bias, the presence of hybrid cells with an amphicrine phenotype suggests that CPACs probably result from an aberration of stem cell differentiation.