Gastric fundic gland polyps: a morphological study including mucin histochemistry, stereometry, and MIB-1 immunohistochemistry

Novel classification of gastric polyps: The good, the bad and the ugly

Gastric polyps (GPs) are increasingly common. On upper endoscopy, they should be examined with white light and occasionally chromoendoscopy, and their morphology classified according to the Paris classification. Most GPs have a typical endoscopic appearance and can be associated with diseases like Helicobacter pylori infection. Histological examination is necessary for an accurate diagnosis. While most polyps are non-neoplastic and do not require treatment, some carry a risk of malignancy or are already malignant. Therefore, understanding the diagnosis, classification, and management of GPs is crucial for patient prognostication. Our new classification categorizes GPs into "good", "bad", and "ugly" based on their likelihood of becoming malignant. We aim to provide descriptions of the endoscopic appearance, pathology, treatment, and follow-up for different GPs, as well as clinical management flowcharts.

Region-specific Wnt signaling responses promote gastric polyp formation in patients with familial adenomatous polyposis

Germline adenomatous polyposis coli (APC) mutation in patients with familial adenomatous polyposis (FAP) promotes gastrointestinal polyposis, including the formation of frequent gastric fundic gland polyps (FGPs). In this study, we investigated how dysregulated Wnt signaling promotes FGPs and why they localize to the corpus region of the stomach. We developed a biobank of FGP and surrounding nonpolyp corpus biopsies and organoids from patients with FAP for comparative studies. Polyp biopsies and polyp-derived organoids exhibited enhanced Wnt target gene expression. Polyp-derived organoids with intrinsically upregulated Wnt signaling showed poor tolerance to further induction, suggesting that high Wnt restricts growth. Targeted genomic sequencing revealed that most gastric polyps did not arise via APC loss of heterozygosity. Studies in genetic mouse models demonstrated that heterozygous Apc loss increased epithelial cell proliferation in the corpus but not the antrum, while homozygous Apc loss was not maintained in the corpus yet induced hyperproliferation in the antrum. Our findings suggest that heterozygous APC mutation in patients with FAP may be sufficient to drive polyp formation in the corpus region while subsequent loss of heterozygosity to further enhance Wnt signaling is not tolerated. This finding contextualizes the abundant yet benign nature of gastric polyps in FAP patient corpus compared with the rare, yet adenomatous polyps in the antrum.

Morphological features of single cells enable accurate automated classification of cancer from non-cancer cell lines

Accurate cancer detection and diagnosis is of utmost importance for reliable drug-response prediction. Successful cancer characterization relies on both genetic analysis and histological scans from tumor biopsies. It is known that the cytoskeleton is significantly altered in cancer, as cellular structure dynamically remodels to promote proliferation, migration, and metastasis. We exploited these structural differences with supervised feature extraction methods to introduce an algorithm that could distinguish cancer from non-cancer cells presented in high-resolution, single cell images. In this paper, we successfully identified the features with the most discriminatory power to successfully predict cell type with as few as 100 cells per cell line. This trait overcomes a key barrier of machine learning methodologies: insufficient data. Furthermore, normalizing cell shape via microcontact printing on self-assembled monolayers enabled better discrimination of cell lines with difficult-to-distinguish phenotypes. Classification accuracy remained robust as we tested dissimilar cell lines across various tissue origins, which supports the generalizability of our algorithm.

Sporadic fundic gland polyps with dysplasia or carcinoma: Clinical and endoscopic characteristics

Fundic gland polyps (FGPs) are the most common gastric polyps and have been regarded as benign lesions with little malignant potential, except in the setting of familial adenomatous polyposis. However, in recent years, the prevalence of FGPs has been increasing along with the widespread and frequent use of proton pump inhibitors (PPIs). To date, several cases of FGPs with dysplasia or carcinoma (FGPD/CAs) have been reported. In this review, we evaluated the clinical and endoscopic characteristics of sporadic FGPD/CAs. Majority of the patients with sporadic FGPD/CAs were middle-aged women receiving PPI therapy and without Helicobacter pylori (H. pylori) infection. Majority of the sporadic FGPD/ CAs occurred in the body of the stomach and were sessile and small with a mean size of 5.4 mm. The sporadic FGPs with carcinoma showed redness, irregular surface structure, depression, or erosion during white light observation and irregular microvessels on the lesion surface during magnifying narrow-band imaging. In addition, sporadic FGPs, even with dysplasia, are likely to progress to cancer slowly. Therefore, frequent endoscopy is not required for patients with sporadic FGPs. However, histopathological evaluation is necessary if endoscopic findings different from ordinary FGPs are observed, regardless of their size. In the future, the prevalence of FGPs is expected to further increase along with the widespread and frequent use of PPIs and decreasing infection rate of H. pylori. Currently, it is unclear whether FGPD/CAs will also increase in the same way as FGPs. However, the trends of these lesions warrant further attention in the future.

Gastritis, Gastric Polyps and Gastric Cancer

Gastric cancer is still an important disease causing many deaths worldwide, although there has been a marked reduction in prevalence during the last few decades. The decline in gastric cancer prevalence is due to a reduction in Helicobacter pylori infection which has occurred for at least 50 years. The most probable mechanism for the carcinogenic effect of H. pylori is hypergastrinemia since H. pylori infected individuals do not have increased risk of gastric cancer before the development of oxyntic atrophy. When atrophy has developed, the carcinogenic process continues independent of H. pylori. Autoimmune gastritis also induces oxyntic atrophy leading to marked hypergastrinemia and development of ECL cell neoplasia as well as adenocarcinoma. Similarly, long-term treatment with efficient inhibitors of acid secretion like the proton pump inhibitors (PPIs) predisposes to ECL cell neoplasia of a different degree of malignancy. Contrasting the colon where most cancers develop from polyps, most polyps in the stomach have a low malignant potential. Nevertheless, gastric polyps may also give rise to cancer and have some risk factors and mechanisms in common with gastric cancer. In this overview the most common gastric polyps, i.e., hyperplastic polyps, adenomatous polyps and fundic gland polyps will be discussed with respect to etiology and particularly use of PPIs and relation to gastric carcinogenesis.

Sporadic foveolar-type gastric adenoma with a raspberry-like appearance in Helicobacter pylori-naïve patients

Sporadic foveolar-type gastric adenoma (FGA) has been described as an extremely rare polyp that is whitish and flatly elevated. However, we recently found that sporadic FGA with a raspberry-like appearance (FGA-RA) is not rare in Helicobacter pylori (H. pylori)-naïve gastric mucosa. We endoscopically or surgically treated 647 patients with gastric epithelial neoplasms in the last 5 years, with 7.7% (50/647) being H. pylori-naïve. Among these, 43 FGA-RAs were diagnosed based on histologic and endoscopic features in 34 patients, who were all enrolled in this retrospective study. All lesions were observed by white-light endoscopy (WLE) and narrow-band imaging with magnification endoscopy (NBIME). We subsequently analyzed their endoscopic and microscopic features and patient characteristics. The patients were 22 males and 12 females aged 57±23 years (mean±2SD). WLE showed raspberry-like small polyps mimicking gastric hyperplastic polyps in the oxyntic gastric compartment (body/fundus). Multiple growths were confirmed in 20.6% (7/34) of the patients. NBIME revealed irregularly shaped papillary/gyrus-like microstructures with abnormal capillaries. Histologically, all lesions were intraepithelial neoplasms, and most of lesions (62.8%, 27/43) exhibited low-grade dysplasia. Immunohistochemically, neoplastic cells featured strong and diffuse MUC5AC expression, negative or very low MUC6 expression, and negative MUC2/CD10 expression. They also showed Ki-67 hyperexpression with a mean labeling index of 59.4±48.7%. The coexistence of fundic gland polyps in the background mucosa was significantly higher in multiple FGA-RA cases than in solitary cases (100% vs. 55.5%, P< 0.05). FGA-RA is a newly suggested histologic variant of sporadic FGA whose occurrence is not rare in daily endoscopic practice.

Effects of obesity on periodontal tissue remodeling during orthodontic movement

INTRODUCTION

Orthodontic movement triggers a sequence of cellular and molecular events that may be affected by different systemic conditions. This study evaluated the effect of obesity on rat periodontal tissue remodeling induced by mechanical orthodontic force.

METHODS

Thirty-two Holtzman rats were distributed into 4 groups: control, obesity induction (O), orthodontic movement (M), and obesity induction and orthodontic movement (OM). Obesity was induced by a high-fat diet for 90 days. After 15 days of orthodontic movement, the animals were killed. Obesity induction was confirmed by animal body weight, adipose tissue weight, and serologic analysis. Periodontal tissue remodeling was evaluated using microcomputed tomography and histologic analysis. The gene expression of adipokines and cytokines in gingival tissues was evaluated.

RESULTS

An increase in body and adipose tissue weight was observed in the obesity induction groups. The O group presented an increase in lipids and blood glucose. The OM group showed a decrease in bone volume fraction and bone mineral density compared with all other groups and a tendency for more rapid tooth movement than the M group. The OM group showed a higher quantity of inflammatory cells and higher Mmp1 expression than the O group. The O and OM groups showed higher Nampt expression than the control group and lower Nampt expression than the M group.

CONCLUSIONS

Obesity modulates periodontal tissue remodeling during orthodontic movement and results in more inflammation and bone loss than in nonobese animals.

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.

GASTRIC FUNDIC GLAND POLYPS: CAN HISTOLOGY BE USEFUL TO PREDICT PROTON PUMP INHIBITORS USE?

BACKGROUND

Fundic gland polyps allegedly increased in frequency in recent decades, and had attracted great attention due to possible association with prolonged proton pump inhibitor therapy. Prolonged use of this drug could cause parietal cell hyperplasia, obstruction of glandular lumen and cystic dilation of the gland.

OBJECTIVE

This study aims to analyze clinical and pathological features of fundic gland polyps in patients with and without proton pump inhibitor therapy in a selected population from Brazil.

METHODS

It was selected a sample of 101 Brazilian patients (78 females and 23 males), from a five years retrospective search of the files from a private pathology laboratory. The patients had an average age of 57 years and we included patients with a histological diagnosis of fundic gland polyp. The clinical data were obtained from their files and all histological slides were reviewed and examined with hematoxylin and eosin (HE) and Giemsa.

RESULTS

Information about the use or non-use of proton pump inhibitors (PPI) was obtained in 84 patient files. In 17 cases we could not determine if PPI were used or not. Among those in which the information was available, a positive history of anti-acid therapy was observed in 63 (75.0%) patients. Parietal cell hypertrophy/hyperplasia and parietal cell protrusions were detected in most slides. Histological findings were identical in PPI users and PPI negative patients. Helicobacter pylori infection was detected in just two samples. Epithelial dysplasia or adenocarcinoma were not observed in our cases. Histopathological analysis of fundic gland polyps could not distinguish between PPI and non-PPI related cases. Parietal cell cytoplasmic protrusions, an alleged marker of prolonged acid suppression therapy, was detected in both groups.

CONCLUSION

Histological features could not discriminate anti-acid therapy related fundic glands polyps in our patients.

Microfluidic on-chip immunohistochemistry directly from a paraffin-embedded section

We present here a novel microfluidic platform that can perform microfluidic on-chip immunohistochemistry (IHC) processes on a formalin-fixed paraffin-embedded section slide. Unlike previous microfluidic IHC studies, our microfluidic chip made of organic solvent-resistant polyurethane acrylate (PUA) is capable of conducting on-chip IHC processes consecutively. A narrow channel wall structure of the PUA chip shows effective sealing by pressure-based reversible assembly with a section slide. We performed both on-chip IHC and conventional IHC processes and compared the IHC results based on the immunostaining intensity. The result showed that the effects of the on-chip deparaffinization, antigen retrieval, and immunoreaction processes on the IHC result were equivalent to conventional methods while reducing the total process time to less than 1/2. The experiment with breast cancer tissue shows that human epidermal growth factor receptor 2 (HER2) classification can be performed by obtaining a clearly distinguishable immunostaining intensity according to the HER2 expression level. We expect our on-chip microfluidic platform to provide a facile technique suitable for miniaturized, automated, and precise diagnostic devices, including a point-of-care device.

Contribution of biomechanical forces to inflammation-induced bone resorption

AIM

This study aimed to evaluate the contribution of biomechanical loading to inflammation-induced tissue destruction.

MATERIALS AND METHODS

A total of 144 adult Holtzman rats were randomly assigned into four experimental groups: control (C), ligature-induced periodontal disease (P), orthodontic movement (OM), and combination group (OMP). On days 1, 3, 7, and 15, following baseline, nine animals from each experimental group were killed. Bone volume fraction (BVF) and bone mineral density (BMD) were measured using micro-computed tomography. Expression and synthesis profile of cytokines and receptors of inflammation in gingival tissues were evaluated by PCR array assay and multiplex immunoassay.

RESULTS

At 15 days, the OMP group presented a significantly (p < 0.05) lower BVF and BMD levels when compared to all the other groups. The OMP group presented the highest number of upregulated protein targets in comparison to the other groups. Furthermore, the gene expression and protein levels of CCL2, CCL3, IL-1β, IL1-α, IL-18, TNF-α, and VEGF were significantly (p < 0.05) higher in the OMP group when compared to the P group.

CONCLUSIONS

In summary, mechanical loading modulates the inflammatory response of periodontal tissues to periodontal disease by increasing the expression of several pro-inflammatory mediators and receptors, which leads to increased bone resorption.

Use of Proton Pump Inhibitors and Risks of Fundic Gland Polyps and Gastric Cancer: Systematic Review and Meta-analysis

BACKGROUND & AIMS

There have been increasing numbers of case reports and observational studies of adverse events in patients receiving long-term therapy with proton pump inhibitors (PPIs). The effects of PPI therapy on risks of fundic gland polyps (FGPs) and gastric cancer have received considerable attention. We performed a systematic review with a meta-analysis of randomized controlled trials and observational studies that assessed these risks.

METHODS

We searched the PUBMED, EMBASE, and Cochrane Central Register of Controlled Trials databases for relevant studies published through July 2015. We calculated pooled odds ratio for FGPs and the risk ratio for gastric cancer in PPI users compared with PPI nonusers using fixed- and random-effects models.

RESULTS

We analyzed data from 12 studies, comprising more than 87,324 patients: 1 randomized controlled trial reporting the effect of PPIs on gastric polyps (location not specified), 6 cohort and 1 case-control studies on FGPs, and 1 cohort and 3 case-control studies on gastric cancer. Pooled odds ratios for FGPs were 1.43 (95% confidence interval, 1.24-1.64) and 2.45 (95% confidence interval, 1.24-4.83) from fixed- and random-effects models, respectively. The pooled risk ratio for gastric cancer was 1.43 (95% confidence interval, 1.23-1.66) from each model. We observed significant heterogeneity among studies reporting on FGPs, but not among studies reporting on gastric cancer.

CONCLUSIONS

Based on a systematic review with meta-analysis, long-term use of PPIs (≥12 months) is associated with an increased risk of FGPs. PPI therapy might also increase the risk of gastric cancer, but this association could be biased, because of the limited number of studies and possible confounding factors.

Sporadic Fundic Gland Polyps With Low-Grade Dysplasia: A Large Case Series Evaluating Pathologic and Immunohistochemical Findings and Clinical Behavior

OBJECTIVES

Fundic gland polyps (FGPs) occur in two clinical settings, sporadic and syndromic. Epithelial dysplasia is rare in sporadic FGPs, and progression data from large series are lacking. The aim of this study was to evaluate the clinical, morphologic, and immunohistochemical features in a large series of sporadic FGPs with epithelial dysplasia.

METHODS

We studied 85 patients with FGPs with low-grade dysplasia (FGPD), including 62 patients with sporadic and 23 with syndromic FGPDs.

RESULTS

Sixty-two patients with sporadic FGPD comprised 29 men and 33 women with a median age of 56 years. The indications for endoscopy were heartburn and follow-up of Barrett esophagus, and 49 patients had a history of proton pump inhibitor use. Morphologically, sporadic and syndromic FGPDs were similar. Immunohistochemical staining for p53 was normal (weak 1+) in all polyps, Ki-67 immunohistochemistry showed staining in the mucus neck and surface epithelium, and nuclear accumulation of β-catenin was observed in 9 of 40 sporadic FGPDs. Twenty-six (42%) patients with sporadic FGPDs had follow-up esophagogastroduodenoscopies with biopsies after a mean period of 14.8 months (nine with more than one follow-up): nine (35%) had no additional polyps, 13 (50%) had nondysplastic sporadic FGPs, and four (15%) had sporadic FGPDs.

CONCLUSIONS

Sporadic FGPDs were seen primarily in middle-aged patients with gastroesophageal reflux. Follow-up data support the indolent nature of these polyps.

Long-term evaluation of oral gavage with periodontopathogens or ligature induction of experimental periodontal disease in mice

OBJECTIVE

To evaluate in long-term periods the destruction of periodontal tissues and bacterial colonization induced by oral gavage with periodontopathogens or ligature experimental periodontal disease models.

MATERIAL AND METHODS

Forty-eight C57BL/6 J mice were divided into four groups: group C: negative control; group L: ligature; group G-Pg: oral gavage with Porphyromonas gingivalis; and group G-PgFn: oral gavage with Porphyromonas gingivalis associated with Fusobacterium nucleatum. Mice were infected by oral gavage five times in 2-day intervals. After 45 and 60 days, animals were sacrificed and the immune-inflammatory response in the periodontal tissue was assessed by stereometric analysis. The alveolar bone loss was evaluated by live microcomputed tomography and histometric analysis. qPCR was used to confirm the bacterial colonization in all the groups. Data were analyzed using the Kruskal-Wallis, Wilcoxon, and ANOVA tests, at 5 % of significance level.

RESULTS

Ligature model induced inflammation and bone resorption characterized by increased number of inflammatory cells and decreased number of fibroblasts, followed by advanced alveolar bone loss at 45 and 60 days (p < 0.05). Bacterial colonization in groups G-Pg and G-PgFn was confirmed by qPCR but inflammation and bone resorption were not observed (p < 0.05).

CONCLUSIONS

The ligature model but not the oral gavage models were effective to induce inflammation and bone loss in long-term periods. Pg colonization was observed in all models of experimental periodontal disease induction, independent of tissue alterations. These mice models of periodontitis validates, compliments, and enhances published PD models that utilize ligature or oral gavage and supports the importance of a successful colonization of a susceptible host, a bacterial invasion into vulnerable tissue, and host-bacterial interactions that lead to tissue destruction.

CLINICAL RELEVANCE

The ligature model was an effective approach to induce inflammation and bone loss similar to human periodontitis, but the oral gavage models were not efficient in inducing periodontal inflammation and tissue destruction in the conditions studied. Ligature models can provide a basis for future interventional studies that contribute to the understanding of the disease pathogenesis and the complex host response to microbial challenge.

Pyloric gland adenoma in Lynch syndrome

The prevalence of gastric cancer associated with Lynch syndrome (LS) is highly variable, and the underlying histologic pathway or molecular mechanisms remain unclear. From 1995 to 2012, 15 patients had been treated for both gastric and colonic adenocarcinomas and diagnosed as LS. In all cases, pathologic review, immunohistochemical analysis for mismatch-repair proteins, and microsatellite instability (MSI) tests were performed. To confirm LS, germline mutation tests and multiplex ligation-dependent probe amplification were performed. All gastric and colonic carcinomas were MSI-high and lost expressions of MLH1/PMS2 in 11 (73%) cases and MSH2/MSH6 in 4 (27%) cases. Remarkably, in a patient with LS and germline mutation of MLH1 gene, pyloric gland adenoma (PGA) transformed to adenocarcinoma during follow-up. In 2 additional cases, PGA was found adjacent to advanced gastric cancers. All PGAs in LS patients were MSI-high and lost expression of mismatch-repair proteins (MLH1/PMS2 in 2 cases and MSH2/MSH6 in 1 case), whereas none of the 14 sporadic PGAs was MSI-high or had lost expression of mismatch-repair proteins. On the basis of these observations, although very rare, we suggest the possibility that PGA may be a precursor lesion to gastric adenocarcinoma in LS and that the mismatch-repair deficient pathway of carcinogenesis is involved early in the gastric carcinogenesis pathway.

SOCS3 expression correlates with severity of inflammation, expression of proinflammatory cytokines, and activation of STAT3 and p38 MAPK in LPS-induced inflammation in vivo

SOCS3 is an inducible endogenous negative regulator of JAK/STAT pathway, which is relevant in inflammatory conditions. We used a model of LPS-induced periodontal disease in rats to correlate SOCS3 expression with the inflammatory status. In vitro we used a murine macrophage cell line to assess the physical interaction between SOCS3 and STAT3 by coimmunoprecipitation. 30 ug of LPS from Escherichia coli were injected in the gingival tissues on the palatal aspect of first molars of the animals 3x/week for up to 4 weeks. Control animals were injected with the vehicle (PBS). The rats were sacrificed at 7, 15, and 30 days. Inflammation and gene expression were assessed by stereometric analysis, immunohistochemistry, RT-qPCR, and western blot. LPS injections increased inflammation, paralleled by an upregulation of SOCS3, of the proinflammatory cytokines IL-1 β , IL-6, and TNF- α and increased phosphorylation of STAT3 and p38 MAPK. SOCS3 expression accompanied the severity of inflammation and the expression of proinflammatory cytokines, as well as the activation status of STAT3 and p38 MAPK. LPS stimulation in a macrophage cell line in vitro induced transient STAT3 activation, which was inversely correlated with a dynamic physical interaction with SOCS3, suggesting that this may be a mechanism for SOCS3 regulatory function.

Gastric adenocarcinoma with chief cell differentiation: a proposal for reclassification as oxyntic gland polyp/adenoma

Gastric adenocarcinoma with chief cell differentiation (GA-CCD) has been reported as a new, rare variant of gastric adenocarcinoma. Only 12 cases in Japanese patients have been described to date, but they demonstrate distinct clinicopathologic features. To further characterize these lesions, we have collected 10 additional cases. Patients ranged in age from 44 to 79 years (mean, 64.2 y) with a relatively equal sex distribution (6 women and 4 men). Stratified by race, 4 patients were Hispanic, 2 were White, 2 were African American, 1 was Asian (Chinese), and the race was unknown for 1 patient. All patients presented with gastroesophageal reflux that prompted an endoscopic examination. The majority of GA-CCDs were identified in the fundus (7 of 10, 70%) and the remaining in the cardia (n=3). Grossly, they were solitary and polypoid, ranging in size from 0.2 to 0.8 cm (mean, 0.4 cm). Histologically, all cases were centered in the deep mucosa, with focal involvement of surface foveolar epithelium in 3 (30%) cases but not the submucosa. The tumors consisted of clustered glands and irregular branching cords of oxyntic epithelium. Thin wisps of radiating smooth muscle separated the epithelium, but desmoplasia was distinctly absent in all cases. The oxyntic mucosa was 1 to 2 cells thick and composed of a mixture of mucous neck, parietal, and chief cells. In 7 of 10 (70%) cases, chief cells were the predominant cell type, whereas the remaining 3 cases consisted primarily of mucous neck cells. The nuclei were mildly enlarged with slight nuclear pleomorphism, but no mitotic figures were identified. In addition, necrosis, lymphovascular invasion, and perineural invasion were absent. Immunohistochemically, GA-CCDs were diffusely positive for MUC6 (10 of 10, 100%) and negative for MUC5AC (0%) and MUC2 (0%). Ki-67 immunolabeling demonstrated variable expression, with the highest areas ranging from 0.2% to 10%. Clinical follow-up was available for 9 of 10 (90%) patients and ranged from 6 to 39 months. One patient had persistence of lesion at 6 months because of incomplete removal, whereas the other 8 were disease free. In summary, GA-CCDs are solitary, mucosal lesions of the gastric cardia/fundus that arise in patients from multiple ethnic backgrounds. Considering that patients within this study and those reported previously have had neither true recurrence nor progression of disease, these lesions are best regarded as benign. Consequently, the term GA-CCD is contradictory and we prefer the descriptive term "oxyntic gland polyp/adenoma" until further studies can clarify the pathogenesis of these lesions and their natural history.

[Massive fundic gland polyposis caused by chronic proton pump inhibitor therapy]

We report two cases of a massive fundic gland polyposis associated with protracted proton pump inhibitor (PPI) therapy. Both patients were females aged 51. On repeated endoscopy, the number of fundic gland polyps was increasing steeply, and they resulted in a passage disorder. In the first case, the enormous number of polyps made endoscopic removal impossible, so the patient was treated by total gastrectomy. Although our case is the second one reported in the world, we would like to draw the attention to this rare complication of long lasting PPI therapy.

Gastric polyps: classification and management

Gastric polyps can be broadly defined as luminal lesions projecting above the plane of the mucosal surface. They are relatively frequent in routine pathology practice, where the main goal is to rule out the possibility of malignancy. Various subtypes of gastric polyps are recognized and generally divided into nonneoplastic and neoplastic. We will review herein only a limited subset of gastric polyps representing the most common or, sometimes, challenging.

Proton pump inhibitors and an emerging epidemic of gastric fundic gland polyposis

Fundic gland polyps are now commonly recognized during endoscopy. These polyps are benign, often multiple and usually detected in the gastric body and fundus. In the past, these polyps were sometimes associated with familial adenomatous polyposis. In recent years, it has become evident that increasing numbers of these polyps are being detected during endoscopic studies, particularly in patients treated with proton pump inhibitors for prolonged periods. In some, dysplastic changes in these polyps have also been reported. Recent studies have suggested that there may be no increase in risk of colon cancer with long-term proton pump inhibitor therapy. While temporarily reassuring, ongoing vigilance, particularly in those genetically predisposed to colon cancer, is still warranted.

Increased risk of fundic gland polyps during long-term proton pump inhibitor therapy

BACKGROUND

It is controversial whether proton pump inhibitor use leads to fundic gland polyp development.

AIM

To determine whether fundic gland polyp development is due to proton pump inhibitor use and to investigate mechanisms involved.

METHODS

Proton pump inhibitor use and the presence of fundic gland polyps were assessed in consecutive patients undergoing oesophagogastroduodenoscopy. Biopsies from fundic gland polyps and gastric mucosa were taken. Dysplasia was graded as negative, low or high grade. Prevalence of parietal cell hyperplasia and parietal cell protrusions and the proportional cystic area were assessed.

RESULTS

599 patients participated, 322 used proton pump inhibitors, 107 had fundic gland polyps. Long-term proton pump inhibitor use was associated with an increased risk of fundic gland polyps (1-4.9 years use: OR 2.2, 95% CI: 1.3-3.8; > or =5 years: OR 3.8, 95% CI: 2.2-6.7) while short-term therapy (<1 year) was not (OR 1.0, 95% CI: 0.5-1.8). Low-grade dysplasia was found in one fundic gland polyp. Fundic gland polyps associated with long-term proton pump inhibitor use had a larger proportional cystic area and higher frequency of parietal cell hyperplasia and parietal cell protrusion.

CONCLUSIONS

Long-term proton pump inhibitor use is associated with an up to fourfold increase in the risk of fundic gland polyps. Risk of dysplasia is negligible. Aetiologically, these polyps seem to arise because of parietal cell hyperplasia and parietal cell protrusions resulting from acid suppression.

Familial adenomatous polyposis

Familial adenomatous polyposis (FAP) is an autosomal-dominant colorectal cancer syndrome, caused by a germline mutation in the adenomatous polyposis coli (APC) gene, on chromosome 5q21. It is characterized by hundreds of adenomatous colorectal polyps, with an almost inevitable progression to colorectal cancer at an average age of 35 to 40 yr. Associated features include upper gastrointestinal tract polyps, congenital hypertrophy of the retinal pigment epithelium, desmoid tumors, and other extracolonic malignancies. Gardner syndrome is more of a historical subdivision of FAP, characterized by osteomas, dental anomalies, epidermal cysts, and soft tissue tumors. Other specified variants include Turcot syndrome (associated with central nervous system malignancies) and hereditary desmoid disease. Several genotype-phenotype correlations have been observed. Attenuated FAP is a phenotypically distinct entity, presenting with fewer than 100 adenomas. Multiple colorectal adenomas can also be caused by mutations in the human MutY homologue (MYH) gene, in an autosomal recessive condition referred to as MYH associated polyposis (MAP). Endoscopic screening of FAP probands and relatives is advocated as early as the ages of 10-12 yr, with the objective of reducing the occurrence of colorectal cancer. Colectomy remains the optimal prophylactic treatment, while the choice of procedure (subtotal vs proctocolectomy) is still controversial. Along with identifying better chemopreventive agents, optimizing screening of extracolonic cancers and applying new radiological and endoscopic technology to the diagnosis and management of extracolonic features are the major challenges for the future.

Chief cell hyperplasia with structural and nuclear atypia: a variant of fundic gland polyp

A case of an unusual variant of fundic gland polyp (FGP) composed of chief cell hyperplasia with structural and nuclear atypia in an 87-year-old woman is presented. Gastrointestinal endoscopy revealed a sessile polyp in the cardia/ corpus transition zone and a polypoid lesion in the fundus. Histologically, the polyp in the cardia/corpus showed a typical appearance of FGP, while that in fundus demonstrated a tumorous lesion composed of irregular branched tubules with nuclear stratification. Despite the structural distortion and nuclear atypia, mitotic figures were absent and MIB-1 positive cells were less than 3%. Immunohistochemically, the cytoplasms of the tubules were negative for gastric mucin and Muc-5AC glycoprotein, but mostly positive for pepsinogen-I, indicating that the proliferated glands consisted mainly of chief cells, not mucous cells. Parietal cells were occasionally found in the glands. At the periphery of the lesion, microcysts composed of parietal cells, chief cells, and mucous cells had developed. Altogether, the polyp in the fundus was diagnosed as an unusual variant of FGP with chief cell hyperplasia. This FGP should be differentiated from tubular adenocarcinoma. Proliferation of chief cells with occasional parietal cells is critical for the differential diagnosis.

Immunohistochemical evaluation of adenomatous polyposis coli, beta-catenin, c-Myc, cyclin D1, p53, and retinoblastoma protein expression in syndromic and sporadic fundic gland polyps

Syndromic and sporadic fundic gland polyps are morphologically indistinguishable but may arise via different pathogenetic mechanisms involving mutations of the adenomatous polyposis coli (APC) and its downstream target beta-catenin genes. Although a higher frequency of dysplasia has been reported in syndromic forms, the risk of developing invasive carcinoma is exceedingly low. The current study was designed to investigate whether syndromic and sporadic fundic gland polyps differ in protein expression of a number of genes that are thought to be important in the control of neoplastic transformation. A total of 262 fundic gland polyps, including 155 syndromic polyps obtained from 35 patients with familial adenomatous polyposis or Gardner's syndrome and 107 sporadic polyps randomly selected from 45 patients with gastroesophageal reflux disease or Barrett's esophagus, were included in this study. Immunohistochemical evaluation showed that loss of immunoreactivity to the antibody against the carboxyl terminus of the APC protein, presumably resulting from APC gene mutations, was more frequent in syndromic than in sporadic cases (40% versus 6.7%, P<0.001). However, immunostaining failed to show aberrant nuclear localization of beta-catenin, a protein regulated by APC, in any of the polyps, irrespective of syndromic or sporadic types. Instead, positive membranous staining for beta-catenin was observed in all the cases. In addition, the expression characteristics of 2 other proteins, c-Myc and cyclin D1, whose genes have been reported to be transcriptionally regulated by the APC/beta-catenin pathway, were similar in these two types of polyps. Furthermore, all cases, including those harboring dysplasia, showed negative nuclear staining for p53 and positive nuclear staining for retinoblastoma (RB). Taken together, these data show a lack of dysregulation in the APC/beta-catenin signaling pathway and in the expression of p53 and RB in fundic gland polyps despite a high frequency of somatic mutations of the APC and beta-catenin genes reported in these polyps. These findings may explain at least in part why fundic gland polyps show a negligible malignant potential even in the presence of dysplasia.

High-grade dysplasia in sporadic fundic gland polyps: a case report and review of the literature

We present a case of fundic gland polyps (FGPs) containing high-grade dysplasia in a 68-year-old man. High-grade dysplasia, and even gastric adenocarcinoma, associated with FGPs have been described in patients with familial adenomatous polyposis (FAP) and attenuated familial adenomatous polyposis (AFAP) but never in non-FAP patients. Two colonoscopies in the past six years virtually rule out FAP and AFAP in our patient. Dysplasia in FGPs from non-FAP patients is extremely rare, and until now only cases of low-grade dysplasia have been described. The literature on dysplasia in FGPs is reviewed briefly. Additional immunohistochemical investigations in this case showed nuclear staining of beta-catenin, increased proliferation and apoptosis in the dysplastic areas of the FGPs. Our case suggests that the malignant potential of FGPs is not limited to FAP-associated FGPs.

High-grade dysplasia in sporadic fundic gland polyps: clinically relevant or not?

Sporadic fundic gland polyps (FGPs) are the most frequent gastric polyps. These FGPs develop almost exclusively in a normal corpus mucosa without Helicobacter pylori infection. This means that they represent an absolutely benign disease (no ulcers, almost no gastric carcinoma and mucosa associated lymphoid tissue (MALT) lymphoma). Most probably there exists a statistically accumulated coincidence rate of sporadic FGPs with colorectal epithelial neoplasias, so it is recommended to consider preventive colonoscopy. In familial adenomatous polyposis (FAP), FGPs are present in up to 80-93% of patients. In such patients, low-grade dysplasia and/or foveolar microadenomas may be present in 44-54% of cases. To date, only three case reports on early gastric carcinoma have been published. In this issue, to the best of our knowledge the first case of a high-grade dysplasia (intraepithelial neoplasia) in a sporadic FGP is reported. Recently, it has been shown that beta-catenin mutations might have led to FGP. Therefore, in the future, patients showing nuclear beta-catenin expression must undergo examination to discover whether this expression may lead to neoplasia. According to the data available at present, such a constellation must be regarded as an extremely rare event.

Positive predictive value of endoscopic features deemed typical of gastric fundic gland polyps

BACKGROUND

Fundic gland polyps (FGPs) are now the most common gastric polyp encountered by endoscopists. However, they have minimal clinical significance. If they could be reliably predicted by endoscopic features, it might prevent the need for and cost of biopsy.

GOALS

To determine the positive predictive value of endoscopic criteria deemed characteristic of FGPs.

STUDY

We prospectively identified 56 consecutive patients with one or more gastric polyps deemed typical of FGPs by endoscopic criteria and submitted them for histologic analysis. Patients with familial adenomatous polyposis were excluded.

RESULTS

Histologic examination confirmed that 50 (89.3%) of the 56 polyps were FGPs. Of the six polyps incorrectly predicted to be FGPs, three were determined to be of normal gastric body-type mucosa, one was uninterpretable secondary to squeeze artifact, one was a lymphoid aggregate with mucosal edema, and one was polypoid regenerative mucosa in the setting of chronic active gastritis and Helicobacter pylori infection.

CONCLUSIONS

As sporadic FGPs are common and can be predicted with a high degree of accuracy based on endoscopic evaluation, it may not be necessary to submit them for pathologic examination. This practice would result in cost savings.

Sporadic fundic gland polyps with epithelial dysplasia : evidence for preferential targeting for mutations in the adenomatous polyposis coli gene

Gastric fundic gland polyps (FGPs) occur in two distinct clinicopathological scenarios: sporadic and familial adenomatous polyposis (FAP) associated. FAP-associated FGPs arise through somatic second hit alterations of the adenomatous polyposis coli (APC) gene and frequently demonstrate epithelial dysplasia (Am J Pathol 2000, 157:747-754). Sporadic FGPs, in contrast, tend to contain beta-catenin gene mutations and only infrequently show dysplasia (Am J Pathol 2001, 158:1005-1010). However, sporadic FGPs with dysplasia have not been previously investigated. We studied 13 sporadic FGPs with surface/foveolar low-grade dysplasia or changes indefinite for dysplasia for alterations in the APC/beta-catenin pathway, using chromosome 5q allelic loss assays and direct DNA sequencing of the mutation cluster region in exon 15 of APC and the phosphorylation region in exon 3 of beta-catenin. In addition, to evaluate for possible additional genetic alterations in FGPs, all cases were evaluated for microsatellite instability using fluorescent-based amplification of a standard panel of five microsatellite markers. Alterations in APC were present in seven (53.8%) FGPs, including two cases with bi-allelic APC inactivation (truncating intragenic mutation plus 5q allelic loss), two cases with APC mutation only, and three cases with 5q allelic loss only. In contrast, only two (15.4%) FGPs contained stabilizing beta-catenin mutations. All 13 FGPs were microsatellite stable. These results indicate that sporadic FGPs with dysplasia/indefinite for dysplasia are molecularly similar to FAP-associated FGPs, and are dissimilar to the more common sporadic nondysplastic FGPs. Mutations in APC and beta-catenin, despite occurring in the same genetic pathway, show differing biological properties, a phenomenon that has previously been demonstrated in colorectal neoplasms. The lack of microsatellite instability in FGPs in this study and of K-ras mutations in a previous study suggests that secondary genetic alterations are rare in both dysplastic and nondysplastic FGPs.

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.

The pathology of epithelial pre-malignancy of the gastrointestinal tract

This chapter deals with pre-malignant epithelial lesions of the gastrointestinal tract that have the potential to become cancers. Pre-malignant lesions are divided into two types: those characterized by dysplastic mucosa and those without dysplasia. Examples of the two types are present in the oesophagus, stomach and intestine. In the oesophagus, dysplasia of the squamous epithelium is a precursor to squamous carcinoma. There are differences in interpretation between Western and Japanese pathologists in the diagnosis of oesophageal squamous lesions. Dysplasia in Barrett's oesophagus is regarded as a precursor of adenocarcinoma. The goal of endoscopic surveillance in Barrett's mucosa is the detection of high-grade dysplasia. There are several problems with our current knowledge of high-grade dysplasia and controversies regarding its management. There are differences in the interpretation of biopsies of gastric epithelial dysplasia between Japanese and Western pathologists. In the colon, pre-malignant lesions include dysplasia seen in inflammatory bowel disease and colonic adenomas. The most significant predictor of the risk of malignancy in patients with inflammatory bowel disease is the presence of dysplasia in colonic biopsies. Because of the similarity of neoplasia throughout the gastrointestinal tract, there have been attempts to unify its classification, terminology and diagnostic criteria internationally, the most recently proposed modified classification of gastrointestinal neoplasia being the Vienna classification. Dysplasia of the columnar mucosa has a similar appearance in Barrett's oesophagus, the stomach and the colon. Criteria for its histological diagnosis and grading are reviewed, with an emphasis on areas of diagnostic difficulty such as interobserver variation, and discrepancies between Western and Japanese pathologists. Implication of the presence of dysplasia that are specific to each organ site are discussed, highlighting weaknesses and controversies in current knowledge.

Sporadic fundic gland polyps: common gastric polyps arising through activating mutations in the beta-catenin gene

Fundic gland polyps (FGPs) are the most common gastric polyps. FGPs traditionally have been regarded as nondysplastic hamartomatous or hyperplastic lesions, but their pathogenesis remains unclear. We have recently shown that somatic adenomatous polyposis coli (APC) gene alterations are frequently present in FGPs associated with familial adenomatous polyposis (FAP), raising the possibility that mutations of the beta-catenin gene affecting the APC/beta-catenin pathway might be involved in the pathogenesis of sporadic FGPs. We analyzed somatic beta-catenin gene mutations in 57 sporadic FGPs from 40 patients without FAP and in 19 FGPs from 13 FAP patients. Direct DNA sequencing of exon 3 encompassing the glycogen synthase kinase-3beta phosphorylation region for beta-catenin was used with confirmation by HIN:fI restriction endonuclease digestion. The foveolar epithelium and dilated fundic glands of the polyps were separately microdissected and analyzed in 22 of 57 sporadic FGPs. Activating beta-catenin gene mutations were present in 91% (52 of 57) of sporadic FGPs. Both the foveolar epithelium and the dilated fundic gland epithelium comprising the polyps were shown to have the same somatic beta-catenin mutation in 21 of 22 (95%) sporadic FGPs. In contrast, beta-catenin gene mutations were not present in any of the 19 FAP-associated FGPs (P: < 0.000001). The high frequency of beta-catenin mutations in sporadic FGPs indicates that these lesions arise through activating mutations of the beta-catenin gene. Beta-catenin mutations in gastrointestinal tract polyps have previously only been demonstrated in a subset of adenomatous (dysplastic) or neoplastic polyps. Sporadic FGPs are therefore the only lesions of the gastrointestinal tract to demonstrate beta-catenin mutations while lacking dysplastic morphology.

Fundic gland polyps in familial adenomatous polyposis: neoplasms with frequent somatic adenomatous polyposis coli gene alterations

Fundic gland polyps (FGPs) are the most common gastric polyps in patients with familial adenomatous polyposis (FAP). FGPs have traditionally been regarded as nonneoplastic, possibly hamartomatous lesions, but the pathogenesis of FGPs in both FAP and sporadic patients remains unclear. FGPs in FAP can show foveolar dysplasia, and rarely invasive gastric adenocarcinoma has been reported in patients with FAP and fundic gland polyposis. Using direct gene sequencing and allelic loss assays at 5q, we analyzed somatic adenomatous polyposis coli (APC) gene alterations in 41 FAP-associated FGPs (20 with foveolar dysplasia, six indefinite for dysplasia, and 15 nondysplastic) and 13 sporadic FGPs. The foveolar epithelium and dilated fundic glands of the polyps were separately microdissected and analyzed in 25 of 41 FAP-associated FGPs and 13 of 13 sporadic FGPs. Somatic APC gene alterations were identified frequently (21 of 41 cases, 51%) in FAP-associated FGPs. Both the foveolar epithelium and the dilated fundic gland epithelium comprising the FGPs were shown to carry the same somatic APC gene alteration in 24 (96%) of 25 cases. Furthermore, there was no difference in the frequency of somatic APC gene alterations between FGPs with foveolar dysplasia (10 of 20, 50%), indefinite for dysplasia (four of six, 67%), and nondysplastic (seven of 15, 47%) in FAP patients (P: = 0.697). In contrast, FGPs from non-FAP patients showed infrequent (one of 13, 8%) APC gene alterations (P: = 0.008). These results show that FGPs in FAP patients are pathogenetically distinct from sporadic FGPs. Somatic, second-hit APC gene alterations, which precede morphological dysplasia in many FAP-associated FGPs, indicate that FGPs arising in the setting of FAP are neoplastic lesions.

Gastric adenocarcinoma associated with fundic gland polyps in a patient with attenuated familial adenomatous polyposis

Familial adenomatous polyposis (FAP) is a rare autosomal dominant precancerous condition of the colon caused by mutations in the adenomatous polyposis coli (APC) tumor suppressor gene. FAP is characterized by the appearance of innumerable adenomatous polyps throughout the large bowel. Fundic gland polyps are the most common gastric lesion in FAP. It is generally believed that fundic gland polyps have little or no potential for malignant transformation in the population at large, and only a few case reports describe the development of high grade dysplasia or gastric adenocarcinoma associated with diffuse fundic gland polyposis in patients with FAP. We report the second case of gastric adenocarcinoma intimately associated with fundic gland polyposis in a family with an attenuated form of FAP. The patient had undergone routine screening per current guidelines because of his known mutation in the APC gene. This suggests that malignant transformation of fundic gland polyps in patients with FAP occur more frequently than previously believed. Current screening recommendations may not be sufficient for patients with FAP or its attenuated forms.

Dysplasia and dysregulation of proliferation in foveolar and surface epithelia of fundic gland polyps from patients with familial adenomatous polyposis

Fundic gland polyps (FGPs) of the stomach are regarded as hamartomatous or hyperplastic/functional polyps that occur sporadically but at increased frequency in patients with familial adenomatous polyposis syndrome (FAP). There is controversy about the histopathology of FGPs, including occurrence of dysplasia. We, therefore, studied dysplasia in 270 sporadic FGPs from 216 patients and 49 FGPs from 24 patients with FAP. We evaluated dysregulation of epithelial proliferation manifested by loss of the normal inverse topographic distribution of Ki-67 proliferation marker and the cyclin-dependent kinase inhibitor p21(WAF1/CIP1) using immunohistochemistry in 27 sporadic FGPs and in 22 FGPs from patients with FAP. Dysplasia in foveolar and surface epithelia occurred in 12 of 49 (25%) FGPs in patients with FAP but in only 3 of 270 (1%) of sporadic FGPs (p < 0.000001). Fourteen of 49 (29%) of FGPs from patients with FAP were indefinite for dysplasia, as contrasted with 8 of 270 (3%) sporadic FGPs (p < 0.00001). The normal inverse topographic distribution of Ki-67 and p21(WAF1/CIP1) was maintained in 20 of 22 (91%) of FGPs negative for dysplasia but was lost in all (8 of 8) FGPs with dysplasia and in 11 of 19 (58%) FGPs that were indefinite for dysplasia (p = 0.00001). The results indicate that dysplasia can occur in foveolar and surface epithelia of FGPs, especially in patients with FAP, and often is preceded by dysregulation of epithelial proliferation when the morphologic abnormalities are indefinite for dysplasia.