Cystic 'hamartomatous' gastric polyps: a disorder of oxyntic glands

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.

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.

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.

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.

Smooth Muscle Hamartoma of the Abomasum in a Calf

This report describes a case of smooth muscle hamartoma of the abomasum in a 6-month-old steer humanely killed because of severe pneumonia. At necropsy, marked thickening of the abomasal wall in the area of the pylorus was found. On cut section, the thickness of the submucosal layer, extending from the submucosa to the muscularis propria, was seen to be increased to 3 cm. The upper (i.e., nearest to the gut lumen) half of the sectioned thickening was composed mainly of adipose-like tissue and the lower half mainly of muscle-like tissue. Histologically, the submucosal layer was composed of fibroadipose tissue, within which were embedded, to varying degrees, numerous well-defined, haphazardly oriented, thin to thick bundles of smooth muscle fibres. This appears to be the first report of smooth muscle hamartoma of the stomach or abomasum in animals, including man.

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.

Fundic gland polyps are not induced by proton pump inhibitor therapy

It is still unclear whether proton pump inhibitors (PPIs) could cause fundic gland polyps (FGPs) in patients without Helicobacter pylori infection. The frequency of FGPs in patients during PPI therapy has not been compared, however with a control group of patients who did not have H. pylori infection and were not undergoing PPI treatment. In a retrospective 12-month study, the frequency of FGPs in 2,251 patients without H. pylori infection receiving PPI therapy (duration of treatment at least 4 weeks) was compared with a control group of 28,096 patients who did not have H. pylori infection and were not receiving PPI therapy. FGPs were identified with an identical frequency in both groups (5.0% in the control and 5.2% in the PPI group). No significant differences were present between the groups with respect to the presence of gastritis or age or sex. Our study shows that a causal pathogenetic relationship between PPI therapy and FGPs is unlikely.

Hyperplastic polyps of the stomach: associations with histologic patterns of gastritis and gastric atrophy

Hyperplastic polyps are common gastric lesions characterized by hyperplastic foveolae with variable amounts of inflamed stroma. Their pathogenesis is unknown, but they have been reported to occur in association with various forms of chronic gastritis, particularly autoimmune gastritis and Helicobacter pylori gastritis. Comprehensive histologic evaluation of the background mucosal pathology in patients with hyperplastic polyps has not been previously performed. We studied 160 patients with gastric hyperplastic polyps and characterized endoscopic and histologic features of the polyps (i.e., location, multiplicity, and presence of dysplasia and adenocarcinoma) and the background gastric mucosa (i.e., intestinal metaplasia, dysplasia, carcinoma, and presence and classification of gastritis). Hyperplastic polyps were most common in the antrum (60%) and were multiple in 20% of patients. Focal intestinal metaplasia of the polyp was present in 16% and dysplasia in 4% of patients. Only one patient (0.6%) had adenocarcinoma within the polyp. Evaluation of the surrounding gastric mucosa showed at least focal intestinal metaplasia in 37% of patients, adenoma or low-grade flat epithelial dysplasia in 2%, and synchronous or metachronous adenocarcinoma in 6%. Eighty-five percent of patients had inflammatory mucosal pathology, most commonly active chronic H. pylori gastritis (25%), reactive or chemical gastropathy (21%), and metaplastic atrophic gastritis of the autoimmune (12%) or environmental (8%) type. These results indicate a strong association between various forms of gastritis and the development of hyperplastic polyps and further emphasize the importance of biopsy of the nonpolypoid gastric mucosa during endoscopic examination.

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.

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.

Parietal cell protrusions in gastric ulcer disease

Oxyntic mucosal biopsy specimens from patients receiving omeprazole therapy have been described as frequently showing characteristic tonguelike protrusions of parietal cell cytoplasm (PCP) into the gland lumen. Although protrusion of parietal cell cytoplasm is believed to be associated with omeprazole therapy and has been implicated in the histogenesis of fundic gland polyps, we have observed it in a wide variety of different conditions unrelated to peptic ulcer disease or omeprazole therapy. To establish the incidence of PCP and analyze its relationship to gastritis, gland dilatation, cystic change, and fundic gland polyps, we studied 400 gastric mucosal biopsy specimens from gastric ulcer patients who were not receiving omeprazole therapy and who did not receive any medications for at least 2 weeks. Severity of each of these changes was graded on a scale of I to III. PCP was observed in oxyntic mucosal biopsy specimens from 60 (15%) patients and was associated with varying grades of chronic superficial or interstitial gastritis in 25 (Helicobacter pylori was identified in 12). Although chronic atrophic gastritis, cystic change, or fundic gland polyps were not identified in any of the cases with PCP, gland dilatation was present in 25 of 60 (42%) biopsy specimens. No consistent linear correlation was observed between increasing grades of PCP and gastritis or gland dilatation. Our findings of PCP in 15% of gastric ulcer patients who were off all medications for 2 weeks indicate that PCP is not always related to omeprazole usage. It appears to be a change encountered in a wide variety of diverse settings and, therefore, should not be used to monitor omeprazole therapy. In gastric ulcer patients, there is no linear correlation between PCP and gland dilatation or severity of gastritis. The lack of association of PCP with such cardinal features of fundic gland polyps as gland dilatation and cystic change suggests that PCP per se has little if any role in the development of such polyps. The exact clinical and functional significance of PCP remain to be established and merits further investigation.

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

Fundic gland polyps are benign lesions, composed of a disorderly arrangement of normal gastric corpus cell types, that occur in a large proportion of patients with familial adenomatous polyposis (FAP) but also develop sporadically in non-FAP patients as well. In this study, the authors evaluated and compared the endoscopic, histological, mucin histochemical, and microscopic stereologic features of 77 fundic gland polyps (FGPs) (15 FAP; 62 non-FAP) to determine if FAP-associated and sporadic lesions are histologically distinct. The authors also analyzed the distribution of mitotically active cells and smooth muscle cells in these lesions using MIB-1 and smooth muscle alpha-actin immunohistochemistry in an effort to determine the pathogenesis of these lesions. The results show that, compared with non-FAP cases, FAP patients with FGPs have a lower male-to-female ratio, a younger mean age at diagnosis, and a higher proportion of cases with multiple polyps. However, no differences were detected between FAP and non-FAP-associated FGPs with respect to any endoscopic, morphological, mucin histochemical, or stereometric features. Eighty-six percent of FGPs showed an increase in smooth muscle content, often in a pericystic distribution. MIB-1-positive proliferative cells were observed not only in the foveolar stem cell region, as expected, but also in the epithelium lining the microcysts and in the gland buds located directly adjacent to the microcysts. The authors conclude that FAP and non-FAP-associated FGPs are histologically identical, and propose that proliferation and subsequent differentiation of aberrantly located proliferative cells in these lesions may explain the histogenesis of FGPs.

Sporadic fundic gland polyps: an immunohistochemical study of their antigenic profile

Fundic Gland Polyps (FGPs) are small sessile (2-5 mm), usually multiple polyps arising in the gastric, acid-secreting mucosa of disputed histogenesis. They have been described in a sporadic form, prevalently in middle aged females, or associated with familial adenomatosis coli-Gardner's syndrome. We performed an immunohistochemical study on 24 sporadic FGPs, using monoclonal antibodies (MAbs) against differentiation markers, class II MHC antigens (HLA-DR), oncofetal and proliferation antigens, aimed to characterize the antigenic profile of the polyps. A preliminary cytogenetic study on five polyps was also done, using an in situ culture method after collagenase treatment. Cytokeratins 8-18 (CAM 5.2 MAb) and 20 (IT-Ks 20.8 MAb), Epithelial Membrane Antigen (EMA) and Chromogranin A were normally expressed by FGPs. FGPs did not express HLA II DR. FGPs did not react with an anti-CEA MAb (F6), but they were frequently positive (22/24, 91.6%) with B72.3 MAb (reacting with the cancer-associated mucin epitope sialyl-Tn). The PC10 MAb (against PCNA or cyclin) showed enhanced expression in the deep glandular-cystic compartment of FGPs; the PCNA index of FGPs was significantly higher than in normal fundic mucosa. The cytogenetic study on the 5 cases analysed, revealed a normal karyotype. We have demonstrated that FGPs express in the paranuclear zone the sialyl-Tn epitope, a side-chain sugar normally masqued in adult gastric mucins, thus revealing an alteration in mucin synthesis; FGPs' higher proliferation index as compared with normal fundic mucosa supports the hypothesis of their hyperproliferative nature.

The World Health Organization's histologic classification of gastrointestinal tumors. A commentary on the second edition

The World Health Organization's (WHO) histologic classification of gastrointestinal tumors has been revised. Although the general basis of classification and the overall outline remain similar to the first edition, advances in the last decade justified changes in classifying certain entities; among them were malignant lymphomas, endocrine tumors, and dysplasias. Several newly recognized entities have also been added.

Upper gastrointestinal pathology in familial adenomatous polyposis: results from a prospective study of 102 patients

Multiple gastric and duodenal biopsy specimens from 102 asymptomatic patients with familial adenomatous polyposis, taken during a prospective endoscopic screening programme were examined. One hundred patients had microscopic gastroduodenal pathology, often in the absence of macroscopic lesions. Adenomas were found in 94 patients in the duodenum, in the second and third parts. Hyperplasia of villous and crypt epithelium was also seen, sometimes in the absence of adenomas: this may be a precursor of neoplastic change. In the stomach fundic gland polyps were the commonest abnormality, seen microscopically in 44 patients. Chronic antral gastritis was common in patients without fundic polyps. Gastric adenomas were present in six patients, all of whom also had duodenal adenomas. If duodenal adenomas in familial adenomatous polyposis have a similar malignant potential to those in the colorectum sequential endoscopy and biopsy are necessary to detect cancer in these patients.

Clinicopathological features and natural history of gastric hamartomatous polyps

The clinicopathological features, chromoendoscopic findings, and natural history of hamartomatous polyps of the stomach were compared with those of gastric hyperplastic polyps. Hamartomatous polyps were found significantly more frequently in adult females than adult males, and all were found significantly more frequently in adult females than adult males, and all were located in the gastric body or the fundus. In general, the number of polyps per patient was less in older patients. Histologically, all these polyps were formed of cystically dilated oxyntic glands and irregularly deformed oxyntic glands. Chromoendoscopic examinations using Congo red showed that the polyps were associated with extensive acid-secreting areas, were all located in acid-secreting areas, and had an acid-secreting function. Colonoscopy and/or radiologic examinations showed that one or a few polyps were frequently also present in the colons of these patients, but none of the families of the patients had a history of gastrointestinal polyposis. One to 11 years after the initial endoscopy, in seven (50.0%) of 14 patients with hamartomatous polyps followed up, the number of polyps decreased significantly.

Solitary polypoid hamartoma of the oxyntic mucosa of the stomach

A solitary pedunculated polyp of the oxyntic mucosa removed from a 66-year-old patient with atrophic gastritis and achlorhydria exhibited distinctive histological features consisting of submucosal, mostly oxyntic-type glands with a smooth muscular framework. Histochemical and immunohistochemical studies demonstrated that the glands were composed of well differentiated chief, parietal, and endocrine cells. Moreover, less frequent glands of the antro-pyloric type were also seen. The lesion was regarded as a previously unrecognized variety of gastric hamartoma.