Intramucosal cysts in the gastric body of patients with Zollinger-Ellison syndrome

Histological analysis of fundic gland polyps secondary to PPI therapy

AIMS

The aim of this study was to clarify the histopathological features of fundic gland polyps (FGPs) in patients treated with proton pump inhibitors (PPIs) and to investigate the mechanism of enlargement of FGPs after PPI treatment.

METHODS AND RESULTS

A total of 196 biopsy specimens of FGPs, which consisted of 87 FGPs in patients treated with PPIs (PPI group) and 109 FGPs in patients treated without PPIs (non-PPI group) were compared histologically using haematoxylin and eosin staining, Ki67 immunohistochemistry and multiplex immunohistochemical stain with Ki67, MUC5AC and MUC6. The significant histological features of FGPs in the PPI group were: larger size of dilated fundic gland cysts, larger number of foveolar and mixture type fundic gland cysts, foveolar cell hyperplasia, parietal cell protrusion, mononuclear cell infiltration and a higher percentage of Ki67-positive cells in the deeper layers of the glands. Multiplex immunohistochemical stain showed that Ki67-positive cells were also positive for MUC5AC, and the Ki67-positive rate was significantly higher in MUC5AC-positive cells of the PPI group than of the non-PPI group. Gene mutations of β-catenin were found in only 9.7% of FGPs in the PPI group.

CONCLUSIONS

Enlargement of fundic gland cysts due to foveolar cell proliferation and parietal cell protrusion might promote the enlargement of FGPs in patients treated with PPIs. β-catenin gene mutations might not be associated with these histological changes of FGPs after PPI treatment.

Cronkhite–Canada syndrome six decades on: the many faces of an enigmatic disease

Cronkhite–Canada syndrome is a rare gastro-enterocolopathy of uncertain aetiology first described almost 60 years ago. It is characterised by diffuse gastrointestinal polyposis sparing only the oesophagus, ectodermal abnormalities and an unpredictable but often fatal clinical course. The disease may demonstrate extremely diverse clinical and endoscopic features, which often leads to a delay in diagnosis. A high index of suspicion and recognition of the characteristic histological findings frequently facilitate a correct diagnosis, but the distribution of the gastrointestinal pathology and its microscopic features may be atypical. The pathologist thus requires a thorough knowledge of both the typical and many atypical faces of this disease, for which various documented therapies often still prove ineffective. Close correlation with clinical findings, including any pertinent ectodermal abnormalities, and careful examination of biopsies derived from polypoid and endoscopically spared mucosa will ensure a timely and correct diagnosis in patients with this enigmatic syndrome.

The morphological and immunohistochemical spectrum of gastric biopsies of patients with absorptive hypercalciuria

Objective

Idiopathic hypercalciuria is characterised by renal stone formation and vertebral osteoporosis. The syndrome displays high clinical variability with patients almost equally distributed between fasting or renal type (prevalent calcium loss) and absorptive type (prevalent increase of intestinal absorption). Absorptive hypercalciuria (AH) is characterised by hypersensitivity of calcium-sensing receptors of antral G cells with normal fasting gastrinaemia and meal hypergastrinaemia. To the best of our knowledge, no study has been published about the morphological aspects of gastric biopsies of patients with AH and the immunohistochemical findings of gastrin-producing G cells. So we studied morphologically and immunohistochemically a group of 38 patients with AH, describing their gastric findings and associated lesion.

Design

All 38 patients had a clinical-laboratory diagnosis of AH with normal fasting hypergastrinaemia and an abnormal rise of gastrinaemia after a standardised meal test. Their 38 antral and 27 body-fundus biopsies, and 5 normal antral and body controls, were stained with H&E, Giemsa stain, polyclonal antiserum anti-Gastrin and a monoclonal antibody anti-Chromogranin A.

Results

Antral biopsies of all 38 patients showed a simple (15) or linear (23) hyperplasia of G cells, whereas only 2 of 27 body biopsies showed a nodular hyperplasia of endocrine cells. In five patients with AH, we found an association with fundic gland polyps (FGPs).

Conclusions

We found in all of the patients with AH a correlation between meal hypergastrinaemia and morphological antral G-cell hyperplasia. Moreover, in five patients, AH was associated with FGPs. We know from literature data that FGPs’ development in Zollinger-Ellison syndrome is statistically associated with hypergastrinaemia. From our present data, we suggest that even in AH the stimulated hypergastrinaemia may have a role in polyp development.

Mechanism of acid hypersecretion post curative gastrinoma resection

BACKGROUND

Some patients with Zollinger-Ellison syndrome post curative gastrinoma resection continue to show gastric acid hypersecretion; however, the mechanism is unknown.

AIM

The aim of this study was to prospectively study acid secretion following curative gastrinoma resection and analyze factors contributing in patients with Zollinger-Ellison syndrome.

METHODS

Fifty patients cured post gastrinoma resection were studied with serial assessments of acid secretory status, cure status and ECL-cell status/activity (with serial biopsies, CgA, urinary N-MIAA). Correlative analysis was performed to determine predictive factors.

RESULTS

Hypersecretion occurred in 31 patients (62%) and 14 had extreme-hypersecretion. There was an initial decline (3-6 months) in BAO/MAO, which then remained stable for eight years. Preoperative BAO correlated with the postoperative secretion, but not other clinical, tumoral, laboratory variables, the degree of postoperative acid suppression or type of antisecretory drug needed. Hypersecretors had greater postoperative ECL changes (P=0.005), serum CGA (P=0.009) and 24-h urinary N-MIAA (P=0.0038).

CONCLUSIONS

Post curative resection, gastric hypersecretion persists long term (mean 8 years) in 62% of patients and in 28% it is extreme, despite normogastrinemia. No preoperative variable except BAO correlates with postresection hypersecretion. The persistent increased ECL-cell extent post curative resection suggests prolonged hypergastrinemia can lead to changes in ECL-cells that are either irreversible in humans or sustained by unknown mechanisms not involving fasting hypergastrinemia and which can result in hypersecretion, in a proportion of which it can be extreme. Whether similar findings may occur in patients with idiopathic GERD treated for prolonged periods (>10 years) with PPIs, at present, is unknown.

Long-term gastric changes in achlorhydric H(+)/K(+)-ATPase beta subunit deficient mice

OBJECTIVE

Hypergastrinemia is known to induce enterochromaffin-like (ECL) cell derived tumors in rodents and man. In this study, we have examined the effect of life-long gastric anacidity and secondary hypergastrinemia in H(+)/K(+)-ATPase beta subunit knockout (KO) mice.

MATERIAL AND METHODS

Female H(+)/K(+)-ATPase beta subunit KO mice and controls were followed up to 20 months before being sacrificed. At termination, intragastric acidity was measured and internal organs were examined for macroscopic and histological changes. Plasma gastrin and serum albumin were measured.

RESULTS

KO mice were anacidic and hypergastrinemic. The oxyntic mucosa was markedly, and with increase in age, hyperplastic with cystic dilatations resembling the changes seen in patients with Menetrier's disease. Serum albumin in KO mice did not differ from controls. KO mice had a marked ECL cell hyperplasia, but only one gastric carcinoma was found.

CONCLUSION

H(+)/K(+)-ATPase beta subunit KO mice develop Menetrier-like changes in the stomach, and may be useful in studying the pathogenesis and treatment of Menetrier's disease. The reason why only one KO mice developed gastric neoplasia whereas the histamine-2 blocker loxtidine has previously been found to regularly induce ECL cell carcinoids in mice is not known.

Effect of antrectomy in hypergastrinaemic female Japanese cotton rats

OBJECTIVE

Female Japanese cotton rats become hypoacidic and hypergastrinaemic from age 2 months and later develop gastric carcinomas in the oxyntic mucosa. Previous studies have demonstrated that carcinogenesis can be halted by a gastrin receptor antagonist and that carcinomas can be induced by a histamine-2 receptor antagonist or partial corpectomy, both of which induce hypergastrinaemia. The aim of the present study was to examine the effect of antrectomy in female cotton rats.

MATERIAL AND METHODS

The animals were either antrectomized (Group 1) or sham-operated (Group 2) 2 months after detection of hypergastrinaemia and terminated 4 months after operation. A third group was antrectomized at age 2 months while still normo-acidic (Group 3) and terminated 6 months after operation.

RESULTS

Antrectomy after 2 months of hypergastrinaemia prevented the development of carcinoma compared with in sham-operated animals, whereas some of the animals that were antrectomized at 2 months of age also developed carcinomas. In Groups 1 and 2 as well as in animals developing carcinomas in Group 3, there was marked hyperplasia of neuroendocrine cells in the oxyntic mucosa expressing chromogranin A, vesicular monoamine transporter (VMAT)-2, ghrelin and somatostatin. Gastrin-positive cells were found adjacent to neoplastic areas in the oxyntic mucosa.

CONCLUSIONS

The removal of antral gastrin by antrectomy halts carcinogenesis in cotton rats, but other mechanisms may also play a role.

Gastritis and carditis

Dyspepsia is a common clinical problem. Its causes include peptic ulcer disease, gastroesophageal reflux, and functional (nonulcer) dyspepsia. A detailed clinical description of pain does not reliably differentiate the cause. Approximately 80% of gastroscopies are performed for the investigation of dyspepsia. "Gastritis" is diagnosed endoscopically in 59% of all stomachs, although in only 3% are the changes severe. Pathologic examination of unselected gastric biopsy specimens reveals that abnormalities are present in 62-73%, but there is only a weak correlation between endoscopic and histologic findings. For these reasons, it is recommended that endoscopic examination should always be accompanied by biopsy. Ideally, biopsies should be taken in a systematic fashion to include sampling of antrum and corpus. Recent evidence suggests that gastric infection by Helicobacter pylori initially presents as a superficial gastritis. Later it may become atrophic with development of intestinal metaplasia. The onset of atrophic changes may be related to the duration of infection, the strain of the infecting organism, associated dietary factors, or as-yet undefined host factors related to immunity. Persistent superficial gastritis predisposes to duodenal ulcer and gastric mucosa-associated lymphoid tissue lymphoma. Atrophic gastritis predisposes to gastric ulcer and adenocarcinoma. Evidence is accumulating that in some patients, pernicious anemia may be an end result of H. pylori-induced atrophic gastritis. Reactive gastropathy is a relatively common finding in gastric biopsies; in most instances it is associated with either reflux of duodenal contents or therapy with nonsteroidal anti-inflammatory drugs. Lymphocytic gastritis, eosinophilic gastritis, and the gastritis associated with Crohn's disease are distinct morphologic entities. Lymphocytic gastritis and eosinophilic gastritis have a variety of clinical associations. Carditis is a controversial topic: currently opinions are divided as to whether it is the result of gastroesophageal reflux or a proximal extension of H. pylori infection from the remainder of the stomach.

Effect of chronic hypergastrinemia on human enterochromaffin-like cells: insights from patients with sporadic gastrinomas

BACKGROUND & AIMS

The effect of chronic hypergastrinemia alone on gastric enterochromaffin-like (ECL) cells in humans is largely unknown because in the common chronic hypergastrinemic states (atrophic gastritis, chronic proton pump inhibitor use), it is not possible to separate the effect of hypergastrinemia and other factors, such as gastritis or atrophy. Studies of patients with sporadic Zollinger-Ellison syndrome (ZES) allow this separation.

METHODS

In 106 patients with ZES, gastric biopsies were taken, and the qualitative ECL cell pattern/grade and the alpha-subunit of human chorionic gonadotropin (alpha-hCG) expression were determined.

RESULTS

In patients with active disease, 99% had ECL hyperplasia and abnormal alpha-hCG staining. Fifty percent had advanced changes in both of these, with 7% having dysplasia and 0% having carcinoids. Advanced ECL cell and alpha-hCG changes were most affected by the level of hypergastrinemia. For ECL cell changes, even mild hypergastrinemia had an effect. Advanced ECL change was also affected by the duration of drug treatment, cure status, and presence of atrophic gastritis, but not by sex or previous vagotomy. The alpha-hCG expression independently predicted dysplasia.

CONCLUSIONS

In humans, chronic hypergastrinemia alone causes advanced ECL cell change and abnormal expression of mucosal alpha-hCG. No threshold for this effect was detected, as reported by some, and in contrast to animal studies, sex and vagal tone did not play a major role. The long-term risk of developing gastric carcinoids with chronic hypergastrinemia is low in patients with sporadic gastrinomas (at least 100 times less than in patients with multiple endocrine neoplasia type 1 with ZES) for at least 15-20 years.

Prospective study of the ability of histamine, serotonin or serum chromogranin A levels to identify gastric carcinoids in patients with gastrinomas

BACKGROUND

Chronic hypergastrinaemia causes gastric enterochromaffin cell proliferation and carcinoid tumours. The only reliable means to diagnose enterochromaffin cell changes/carcinoids is by biopsy.

AIM

To assess whether serum histamine, chromogranin A or serotonin and urinary N-methylimidazoleacetic acid or 5-hydroxyindoleacetic acid correlate with advanced enterochromaffin cell changes or gastric carcinoids in patients with gastrinomas.

METHODS

Consecutive patients (n=145) had the above assays and endoscopy with gastric biopsies.

RESULTS

Lower N-methylimidazoleacetic acid and chromogranin A levels (P < 0.0001) occurred in disease-free patients. In patients with active disease, the fasting serum gastrin levels correlated (P < 0.0001) with both chromogranin A and N-methylimidazoleacetic acid levels. Chromogranin A (P=0.005), but not N-methylimidazoleacetic acid, serotonin, 5-hydroxyindoleacetic acid or histamine levels, correlated with the enterochromaffin cell index. Carcinoids, but not advanced enterochromaffin cell changes only, were associated with higher chromogranin A and N-methylimidazoleacetic acid levels.

CONCLUSIONS

Serum chromogranin A levels and urinary N-methylimidazoleacetic acid levels, but not serum histamine or serotonin or urinary 5-hydroxyindoleacetic acid, correlate with the presence of gastric carcinoids. However, no assay identified patients with advanced enterochromaffin cell changes only with high sensitivity/specificity. Thus, N-methylimidazoleacetic acid and chromogranin A levels are unable to identify patients with advanced changes in enterochromaffin cells and therefore neither can replace routine gastric biopsies.

Gastric mucosal morphological consequences of acid suppression: a balanced view

In the chapter, an analysis of the literature on the relationship between Helicobacter pylori, the use of proton pump inhibitors and the development of atrophic gastritis is presented, and the difficulties of classifying gastritis and the new possibilities of quantifying chronic inflammation by morphometric analysis are discussed. The issue surrounding the necessity of eradicating H. pylori in H. pylori-positive patients has still not been solved. Most studies have now accepted that proton pump inhibitors indeed accelerate the onset of atrophic gastritis in H. pylori-positive patients, but evidence against such an association was published in one recent (Scandinavian) study; conclusions from this study have, however, been challenged by several groups. Some data are available on the efficacy of H. pylori eradication with regard to the prevention of atrophy. The limited significance of the development of parietal cell protrusions and fundic gland cysts is better understood, but much less is known of the development and long-term consequence of H. pylori-induced autoimmune gastritis. Finally, recent studies in H. pylori-positive patients indicate that treatment with proton pump inhibitors may promote bacterial N-nitrosation formation. These data taken together suggest that the eradication of H. pylori may be based not only on morphological arguments, but also on bacterial alterations in the gastric milieu.

Pancreatic endocrine tumors

Pancreatic endocrine tumors are rare but have long held a fascination for clinicians because of the physiologic derangements that they can cause, and the dramatic corrections that can be achieved by appropriate management. In the year reviewed in this article, the literature again demonstrated the ongoing interest and research in this area. In particular, the areas of gastrinoma, insulinoma, and multiple endocrine neoplasia type 1 have received careful attention.