Clinicopathologic characteristics and mucin expression in Brunner's gland proliferating lesions

Benign Tumors and Tumor-Like Conditions of Ampulla and Small Intestine: The PathologyOutlines.com Review

Small intestine and ampulla can be involved in a heterogeneous group of benign tumors and tumor-like diseases, potentially mimicking malignant neoplasms. In-depth knowledge of them is critical for practicing pathologists since they represent potential pitfalls in routine diagnostic activity. Such conditions include the following: (1) Brunner gland lesions, including Brunner gland hyperplasia and hamartoma; (2) polyps, such as adenoma, hyperplastic, hamartomatous, and inflammatory; (3) mesenchymal proliferations encompassing inflammatory fibroid polyp, inflammatory myofibroblastic tumor, leiomyomas, lipomas, and lipomatosis of the ileocecal valve; (4) fibrosis-associated diseases, such as idiopathic retroperitoneal fibrosis, reactive nodular fibrous pseudotumor, and sclerosing peritonitis; (5) disorders of lymphatic vessels, including lymphangiectasia and lymphangiomas; and (6) other rare conditions/miscellanea, such as enteritis cystica profunda, intussusception, ischemia, and pneumatosis cystoides intestinalis. This review, inspired by the content of the PathologyOutlines website (https://www.pathologyoutlines.com), aims to provide a reference point in this complex scenario, summarizing the essential histopathological features of all these entities for better addressing routine practice and differential diagnoses.

The Characteristics and Treatment Outcomes of 71 Duodenal Brunner's Gland Adenomas with Endoscopic Submucosal Dissection

INTRODUCTION

The aim of this study was to investigate outcomes of patients with duodenal Brunner's gland adenomas (BGAs) that were treated endoscopically.

METHODS

We identified 71 consecutive patients treated at our center with endoscopic submucosal dissection (ESD) for their duodenal tumors diagnosed pathologically as BGAs over the period between January 1, 2011 and December 31, 2021. We retrospectively analyzed our experience and short- and long-term outcomes of ESD therapy on patients with BGAs.

RESULTS

Among 71 BGA patients with an average age of 57 ± 11.7 years (range: 30-82), 48 (67.6%) were male and 23 (32.4%) were female. The accuracy of preoperative diagnosis with endoscopic ultrasonography was 44.0% (22/50). The H. pylori infection was found in 29 patients (29/71, 40.8%). The median size of BGAs was 1.5 cm (interquartile range [IQR] 0.8-2.7 cm). The most common location was the duodenum bulb (50/71, 64.8%). For the ESD procedure, the median operation time was 15.0 min (IQR 9.5-25.5 min). The en bloc and the complete resection rates were 97.2% and 92.3%, respectively. ESD-related mild acute obstructive pancreatitis was present in 2 patients (2/4, 50%) with BGAs located in the ampulla region. During the follow-up period, 1 patient with a positive peripheral margin experienced tumor recurrence 2 years after the initial ESD. There was no disease-related death for the cohort.

CONCLUSION

ESD was an effective and safe therapeutic option for BGA patients with excellent outcomes. Long-term follow-up is needed.

Brunner Gland Hamartomas-Uncommon Presentations and Endoscopic Management

Brunner gland hamartoma (BGH) is a rare condition that requires a high clinical suspicion to diagnose. Large hamartomas may initially present with iron deficiency anemia (IDA) or symptoms suggesting intestinal obstruction. Barium swallow may demonstrate the lesion, but endoscopic evaluation is the acceptable first line management unless a concern for underlying malignancy. The present case report and literature review highlight the uncommon presentations and endoscopic role in large BGHs management. Internists should consider BGH in their differential, especially in patient with occult bleeding, IDA, or obstruction, which can be treated with endoscopic resection of large sized tumors by trained experts.

Brunner’s gland hyperplasia associated with lipomatous pseudohypertrophy of the pancreas presenting with gastrointestinal bleeding: A case report

BACKGROUND

Brunner’s gland hyperplasia (BGH) is a rare benign lesion of the duodenum. Lipomatous pseudohypertrophy (LiPH) of the pancreas is an extremely rare disease. Because each condition is rare, the probability of purely coincidental coexistence of both conditions is extremely low.

CASE SUMMARY

We report a 26-year-old man presenting to our hospital with symptoms of recurrent upper gastrointestinal bleeding. Upper gastrointestinal endoscopy showed a huge pedunculated polypoid lesion in the duodenum with bleeding at the base of the lesion. Histopathological examination of the duodenal biopsy specimens showed BGH. Besides, abdominal computed tomography and magnetic resonance imaging revealed marked fat replacement over the entire pancreas, confirmed by histopathological evaluation on percutaneous pancreatic biopsies. Based on the radiological and histological findings, LiPH of the pancreas and BGH were diagnosed. The patient refused any surgical intervention. Therefore, he was managed with supportive treatment. The patient’s symptoms improved and there was no further bleeding.

CONCLUSION

This is the first well-documented case showing the coexistence of LiPH of the pancreas and BGH.

Brunneroma: an infrequent duodenal neoplasm

Brunneroma or Brunner gland's adenoma is an uncommon type of gastrointestinal tumor, frequently asymptomatic and rarely has malignant transformation. After an initial finding at upper endoscopy, endoscopic ultrasound and computer tomography are helpflul in planning treatment. Resection offers a definitive diagnosis.

Brunner's Gland Hamartoma of the Duodenum: A Literature Review

Brunner's gland hamartoma is a benign tumor of the duodenum, but has malignant potential with a very low risk of progression into adenocarcinoma. It is uncommon with a frequency of less than 1.0% among the primary tumors of the small intestine. In addition, its clinical manifestations are nonspecific, etiology remains unclear, and treatment strategy needs to be further refined. This literature review mainly discusses the epidemiology, clinical features, possible etiology and pathogenesis, diagnostic methods, malignant potential, treatment, and prognosis of Brunner's gland hamartoma.

Non-conventional dysplasias of the tubular gut: a review and illustration of their histomorphological spectrum

The increasing use of gastrointestinal endoscopic procedures has led to the recognition by histopathologists of non-conventional (or special-type) dysplasias of the gastrointestinal tract. These lesions can be recognised in association with prevalent underlying gastrointestinal conditions, such as Barrett oesophagus, chronic atrophic gastritis, and inflammatory bowel disease. The diagnosis of these special types can be challenging, and their biological behaviours are not fully characterised. The aim of this review is to provide a global view of non-conventional dysplastic lesions observed in the various segments of the tubular gastrointestinal tract and describe their salient features. Furthermore, as the clinical implications of these various subtypes have not been broadly tested in practice and are not represented in most management guidelines, we offer guidance on the best management practices for these lesions.

The pathology of gastric and duodenal polyps: current concepts

The liberal use of upper endoscopy has led to an increased detection of gastric and duodenal polyps, which are identified in as many as 6 and 4.6% of patient examinations, respectively. Gastroduodenal polyps are a heterogeneous group of lesions that can be neoplastic or non-neoplastic (e.g. hyperplastic or heterotopical). Most polyps present characteristic topographical features, as well as endoscopic appearance and size. Evaluation of the surrounding mucosa is essential in assessing the underlying pathology (e.g. Helicobacter pylori, autoimmune gastritis or inherited polyposis syndromes). Phylogenetically, gastric and duodenal polyps can be classified according to the epithelial compartment from which they derive. Polyps that arise from the surface epithelium can either be of foveolar or intestinal type, and they can develop from either the native mucosa or the metaplastic epithelium (gastric intestinal metaplasia or duodenal foveolar metaplasia). Other polyps develop from the deeper glandular component, such as pyloric/oxyntic gland derived subtypes. In this review we focus upon epithelial polyps, with an emphasis on the most common and clinically relevant lesions, and present recently described entities.

High-fat Diet Alters the Glycosylation Patterns of Duodenal Mucins in a Murine Model

High-fat diet (HFD) alters the glycosylation patterns of intestinal mucins leading to several health problems. We studied by histochemical and lectin-binding methods mucin alterations in the duodenum of mice fed a HFD for 25 weeks. Histochemical methods included periodic acid-Schiff, alcian blue pH 2.5, and high-iron diamine. Lectin-binding experiments were performed with SBA, PNA, WGA, MAA-II, SNA, ConA, UEA-I, LTA, and AAA. SBA, PNA, WGA, MAA-II, and SNA were tested also after desulfation and ConA after periodate-sodium borohydrate treatments (paradoxical ConA). Duodenal mucins are secreted by Brunner's glands and goblet cells in the villi. Brunner's glands of HFD mice showed increased secreting activity and a general reduction of glycosylated residuals, such as fucose and terminal α1,4-linked GlcNAc. Moreover, a general reduction of glycosylated residuals in the goblet cells of villi such as the fucosylated and sulfated ones was observed. Since the cited residuals are involved in cytoprotective and cytostatic functions, as well as in interactions with the intestinal microbiota and protection against parasites and inflammatory disorders, we conclude that HFD can predispose duodenum to several possible health disorders.

Clinicopathological features of pyloric gland adenomas of the duodenum: a multicentre study of 57 cases

AIMS

To determine the clinicopathological features of pyloric gland adenomas (PGA) that arise in the duodenum.

METHODS AND RESULTS

Fifty-seven cases of duodenal PGA were identified and analysed from 56 patients. Clinicopathological and immunohistochemical analyses were performed. PGA tend to occur in older individuals (median age = 73.5), with a slight female predominance (25 males, 31 females). PGA arise more commonly in the proximal duodenum (68.75% in D1, 25% in D2 and 6.25% in D3) and usually present as mucosal nodules (98.2%) or plaques (1.8%), with a mean size of 14.8 mm. There is associated gastric heterotopia in 22.8% of cases. PGA showing features of high-grade dysplasia were significantly larger in size than PGA, showing only low-grade dysplasia (23.1 versus 8.7 mm; P = 0.0001) and more likely to show a tubulovillous rather than a pure tubular architecture (P = 0.025). In our series, 10 of 56 patients had intramucosal or invasive carcinoma associated with the duodenal PGA (17.9%). Three of these carcinomas showed lymph node metastasis. Following definitive treatment, local recurrence occurred in only three patients.

CONCLUSIONS

Duodenal PGA tend to occur in the proximal duodenum of older individuals. Larger size and tubulovillous architecture correlates with high-grade dysplasia and associated adenocarcinoma. The low recurrence rate of these lesions would suggest that endoscopic management is appropriate, provided that the lesion can be completely resected.

A giant Brunner's gland hamartoma being treated as a pedunculated polyp: a case report

BACKGROUND

With the development and application of endoscopic technology, most pedunculated polyps can be absolutely resected with a complete specimen by hot snare polypectomy (HSP). Brunner's gland hamartoma (BGH) is a rare benign small bowel tumor. The majority of BGH measuring about 2 cm in diameter, rarely larger than 5 cm. Most patients are asymptomatic, some may present with gastrointestinal hemorrhage or intestinal obstruction. Symptomatic larger lesions leading to bleeding or obstruction should be excised either endoscopically or surgically. Whether it is safe and effective that removing a BGH measuring about 7 cm by HSP is not known.

CASE PRESENTATION

Here, we reported a rare case of a proximal duodenum pedunculated mass measuring about 7 cm which was responsible for the patient's severe anemia. we treated it as a pedunculated polyp. After being pretreated the stalk with an endoloop which was placed around the base of the mass to prevent post-polypectomy bleeding (PPB), the pedunculated BGH was removed by HSP completely. The stalk of the mass was negative. We achieved a curative resection.

CONCLUSION

It is a safe and effective for our patient to treat the pedunculated BGH measuring about 7 cm as a pedunculated polyp and remove it by HSP. And future prospective studies in larger cohorts are needed to confirm it.

Brunner's Gland Hyperplasias and Hamartomas in Association with Helicobacter pylori

BACKGROUND

The proliferative lesions of the Brunner's glands (BGs) are hyperplasia and hamartomas, and they are usually asymptomatic and very rarely diagnosed. The aetiology of these lesions is not yet clear. The aim of this study is to evaluate the clinical presentations of patients with BG hyperplasia and hamartomas and to assess the pathological features of these lesions in association with Helicobacter pylori (H. pylori).

METHODS

Our retrospective study included patients who underwent upper gastrointestinal system endoscopy between 2010 and 2015. The hospital records of 18 patients diagnosed with hyperplasia or hamartoma of BG were reviewed for the clinical and pathological findings. Data from patients with BG lesion were compared with 37 patients who had nonspecific duodenitis as the control group.

RESULTS

Female/male ratio in our study sample was 1/1. The age range was between 16 and 85 years with a mean age of 48.61. BG hyperplasia and hamartomas were found in 72.22 and 27.78% of the patients, respectively. The rate of H. pylori in gastric mucosa was 43.2% in the control group and 66.7% in the BG lesion group. In the BG lesion group, the rate of H. pylori was higher. H. pylori was identified in 60% of BG hamartomas and in 69.2% of hyperplastic BGs.

CONCLUSION

Our study demonstrated that H. pylori may play an important role in the development of BG hyperplasia and hamartomas in association with chronic gastritis and duodenitis. This is probably due to chronic irritation.

Duodenal Epithelial Polyps: A Clinicopathologic Review

CONTEXT.—

Duodenal epithelial polyps are reported in 1.5% to 3% of individuals referred for upper endoscopy. Most duodenal epithelial polyps are asymptomatic and nonneoplastic; however, a small subset is neoplastic and may progress to adenocarcinoma. Recent advances in immunohistochemical and molecular techniques have helped further characterize these polyps, shedding light on their origin, classification, and risk of progression to adenocarcinoma.

OBJECTIVE.—

To provide a comprehensive clinicopathologic review of nonneoplastic and neoplastic duodenal epithelial polyps, with particular emphasis on recent developments in classification schemes and risk stratification based upon immunohistochemical and molecular profiles.

DATA SOURCES.—

This review is based on peer-reviewed literature and the authors' experiences.

CONCLUSIONS.—

In this review we provide an update on the clinicopathologic, immunohistochemical, and molecular features of duodenal epithelial polyps and discuss the surveillance recommendations and treatment options available. Particular attention should be placed on recognizing duodenal adenomas with intestinal, gastric, and serrated phenotype, as they have an increased risk of malignant transformation if not completely excised.

Duodenal Adenocarcinoma of Brunner Gland Origin: A Case Report

We report a case of adenocarcinoma originating from the duodenal Brunner glands in a 47-year-old female patient. The lesion was 0.8 cm in extent and located at the posterior wall of the first part of the duodenum. Histologically, the tumor showed transition from non-neoplastic Brunner glands through dysplastic epithelium into adenocarcinoma. The carcinoma cells were strongly positive for MUC6 protein, which is an epithelial marker for the Brunner glands. Tumor protein p53 was overexpressed in the carcinoma cells, but not in the non-neoplastic or dysplastic epithelium. Dystrophic calcification was predominant. This is the first case report of duodenal adenocarcinoma of Brunner gland origin in Korea.

Sporadic Non-ampullary Duodenal Adenoma Overriding the Cystic Dilatation of Brunner's Gland Hyperplasia

Sporadic non-ampullary duodenal adenoma is uncommon and found incidentally during endoscopic examinations. Brunner's gland hyperplasia is commonly encountered during endoscopic examinations. Adenomas arising from Brunner's gland hyperplasia originate from the glandular cells, and the surface epithelia are usually intact. Little has been reported on adenomas originating from the surface epithelium that overrides Brunner's gland hyperplasia. Here, we report a case of a sporadic non-ampullary duodenal adenoma overriding the cystic dilatation of Brunner's gland hyperplasia.

Saving from unnecessary pancreaticoduodenectomy. Brunner's gland hamartoma: Case report on a rare duodenal lesion and exhaustive literature review

INTRODUCTION

Brunner's gland hamartoma (BGH) is an infrequently encountered, benign, polypoid proliferation of Brunner's glands. Usually these lesions are asymptomatic, just only occasionally presenting with duodenal obstruction or bleeding signs and mimicking a tumoral lesion.

CASE PRESENTATION

A 72-year-old male, referred for recurrent vomiting and epigastralgia, was investigated and all preoperative findings were suggestive of a tumour of the duodenum. During the scheduled pancreaticoduodenectomy a mass, resultant to a polyp, was palpatory felt inside the duodenum and then successfully and completely resected through a duodenotomy avoiding surgical overtreatment and connected postoperative morbidities. Histological analysis showed hyperplasia of Brunner's glands correspondent to a Brunner's gland hamartoma. BGH was undiagnosed before surgery, due to its particular sub-mucosal growth simulating an expanding process starting from the duodenum, and secondly due to unsuccessful biopsies performed during endoscopic procedure.

CONCLUSION

BGH is a rare lesion featuring, when symptomatic, obstructive or bleeding symptoms. Surgical treatment represents the gold standard approach in case of lesions that are technically impossible to remove endoscopically or in case of an undiagnosed lesion. Herein, we report a case of a patient presenting with a duodenal lesion mimicking, in all preoperative findings, a tumour of the duodenum. Duodenotomy and resection of the BGH provided a definitive cure avoiding surgical overtreatment. An intraoperative deep analysis of all surgical cases still remain crucial for a right therapeutic choice even in a new era for surgical technology. For similar intraoperative findings we recommend this technique.

Clinicopathological characteristics of duodenal epithelial neoplasms: Focus on tumors with a gastric mucin phenotype (pyloric gland-type tumors)

Objective

Epithelial tumors less commonly occur in the duodenum than in the stomach or large intestine. The clinicopathological characteristics of duodenal epithelial tumors remain a matter of debate. We therefore studied resected specimens to investigate the clinicopathological characteristics of duodenal epithelial tumors.

Materials and methods

Among duodenal epithelial tumors resected endoscopically or surgically in our hospital, we studied the clinicopathological characteristics of 110 adenomas or intramucosal carcinomas. The grade of atypia of all tumors was classified into 3 groups according to the World Health Organization (WHO) 2010 classification. The tumors were immunohistochemically evaluated to determine the frequency of differentiation toward fundic glands.

Results

As for patient characteristics, there were 76 men (75.2%) and 25 women (24.8%), with a median age of 65 years (range, 34 to 84). The tumors most commonly arose in the first to second part of the duodenum. Many lesions were flat, and the median tumor diameter was 8.0 mm. The lesions were classified into 2 types according to mucin phenotype: intestinal-type tumors (98 lesions, 89.1%) and gastric-type tumors (12 lesions, 10.9%). Intestinal-type tumors were subdivided into 2 groups: tubular-type tumors (91 lesions, 82.7%) and tubulovillous-type tumors (7 lesions, 6.4%). Gastric-type tumors were classified into 2 types: foveolar type (3 lesions, 2.7%) and pyloric gland-type (PG) tumors (9 lesions, 8.2%). The grade of atypia was significantly higher in gastric-type tumors (p<0.01). PG tumors were gastric-type tumors characterized by pyloric glands and findings suggesting differentiation toward fundic glands.

Conclusions

About 10% of the duodenal tumors had a gastric-type mucin phenotype. Gastric-type tumors showed high-grade atypia. In particular, PG tumors showed similarities to PG tumors of the stomach, such as differentiation toward fundic glands.

A Giant Brunneroma Causing Gastrointestinal Bleeding and Severe Anemia Requiring Transfusion and Surgery

Brunner's gland hamartoma, also called hyperplasia, adenoma, and Brunneroma, is an extremely rare benign proliferative lesion of Brunner's glands in the duodenum. While being mostly small and asymptomatic, they can result in gastrointestinal bleeding and obstruction. We report the case of a 54-year-old man presenting with melena and severe anemia requiring blood transfusion. CT scans showed a large mass of 8 cm in diameter, presumably arising in the duodenum. Endoscopic biopsies were not conclusive. As we were unable to determine the nature of the mass preoperatively and due to the severe symptoms, its size, and the uncertain malignant potential, a classic Whipple procedure was performed. The resected specimen showed extensive proliferation of Brunner's glands without signs of malignancy.

Endoscopic Resection of a Pedunculated Brunner's Gland Hamartoma of the Duodenum

A 68-year-old Japanese woman presented with a solitary pedunculated polyp in the duodenum. Endoscopic ultrasonography showed multiple cystic structures in the polyp. The polyp was successfully resected by endoscopic snare polypectomy and pathologically diagnosed as Brunner's gland hamartoma. Because hamartomatous components were not identified in the stalk of the polyp, we speculate that the stalk developed from traction of the normal duodenal mucosa. When a solitary, pedunculated polyp with cystic structure within the submucosa is found in the duodenum, Brunner's gland hamartoma should be considered in the differential diagnosis, despite the rarity of the disease. This case underscores the usefulness of endoscopic ultrasonography for the diagnosis of duodenal subepithelial tumors.

Brunner's gland cyst in combination with gastrointestinal stromal tumor: A case report

Brunner's gland cysts are rare benign lesions that are mainly observed in the first and the second regions of the duodenum. Patients with Brunner's gland cyst demonstrate no specific symptoms. The present study reports the case of a patient with Brunner's gland cyst located in the duodenum in combination with a gastrointestinal stromal tumor (GIST) in the same region. To the best of our knowledge, the present study reports the first case of Brunner's gland cyst with GIST. A 58-year-old female patient was referred to Tianchang Hospital of Traditional Chinese Medicine (Tianchang, China) with a one-month history of upper abdominal discomfort, diarrhea and recurrent vomiting following the intake of food. Upper gastrointestinal endoscopy and a computed tomography scan revealed the presence of a round, cystic-like lesion with internal low density located within the duodenum. Pathological examination revealed that the cyst measured 0.3 cm in diameter and was consistent with a diagnosis of Brunner's gland cyst. Histopathology revealed that the cyst possessed characteristics of GIST. The patient underwent surgical exploration and tumor resection, and was discharged 2 weeks post-surgery. During the 12 month post-operative follow-up period, the outcome of the patient was good. This case study of Brunner's gland cyst combined with GIST enriches the present literature and promotes better understanding of the two diseases. Further investigation is required to explain the mechanism and association between the two rare diseases.

Comparative glycopattern analysis of mucins in the Brunner's glands of the guinea-pig and the house mouse (Rodentia)

The mucins secreted by the Brunner's glands and the duodenal goblet cells of the Guinea-pig and the house mouse were compared by conventional and FITC-conjugated lectin histochemistry. Methylation/saponification and sialidase digestion were performed prior to lectin binding to detect the residues subterminal to sulfated groups and sialic acid, respectively. In the Guinea-pig the Brunner's glands produce class-III stable sulfosialomucins. Sialic acid is mostly 2,6-linked to galactose or to N-acetylgalactosamine and is in part O-acetylated in C7, C8, and C9. Sulfated groups are probably linked to sialic acid and N-acetylgalactosamine. Terminal residuals of N-acetylglucosamine, galactose, N-acetylgalactosamine and fucose linked in α1,2, α1,3, and α1,4 are also present. Duodenal goblet cells of the Guinea-pig present a lower number of residuals in respect to the Brunner's glandular ones, with sialic acid and N-acetylgalactosamine subterminal to sulfated groups. In the house mouse the Brunner's glands produce class-III stable neutral mucins, binding to same lectins as in the Guinea-pig except for those specific to sialic acid. A diversity of fucosylated residuals higher than in the Guinea-pig is observed. The mouse duodenal goblet cells lack stable class-III mucins, have little sialic acid and present a lower number of residuals in respect to the correspondent Brunner's glands. Regulation of the acidic intestinal microenvironment, prevention of pathologies and hosting of microflora can explain the observed results and the differences observed between the two rodents.

Duodenal mucosal damage is associated with proliferative activity of Brunner's gland hamartoma: a case report

Background

Brunner’s gland hamartoma is a rare tumor, predominantly found in the fifth to sixth decades of life. Generally, it is a single pedunculated polyp, rarely larger than 5 cm. Asymptomatic cases are found incidentally, but cases with a large polyp tend to have gastrointestinal bleeding and/or obstructive symptoms. Polyp size increases in a time-dependent manner, however, the growth mechanism is unknown. We report a Japanese male case in his mid-twenties with an over 6 cm sized polyp.

Case presentation

A 26-year-old man presented black stools and anemia. Endoscopic examination revealed a large pedunculated polyp at gastroduodenal junction. The polyp, subsequently resected by distal gastrectomy, was lobulated with random surface erosions and sized 6.4 × 3 cm. Histological examination revealed that the polyp arose from duodenal mucosa and was composed of hyperplastic Brunner’s glands in lobules separated by fibromuscular septa, associated with lymphocytic infiltrate and lymphoid follicles. No evidence of malignancy was found. Thus, the lesion was diagnosed as Brunner’s gland hamartoma. Further immunohistochemical studies indicated that gastric foveolar metaplasia is associated with surface epithelium covering upper two thirds of the polyp, showing immunohistochemical positivity for mucin 5 AC (MUC5AC). Below the metaplastic surface epithelium, Brunner’s glands had high proliferative activity (MIB-1 labeling index: 7.9%). The similar staining pattern was observed at surface erosive sites (MIB-1 labeling index in Brunner’s glands: 9%). On the other hand, surface epithelium in the lower side of the polyp still preserved intestinal nature, containing CDX2-positive nuclei and MUC2-positive goblet cells. Brunner’s glands below the surface epithelium with intestinal characteristics showed low proliferative activity (MIB-1 labeling index: 0.77%).

Conclusion

Proliferative activity of Brunner’s glands was high at the sites with surface erosion and also below the epithelium showing gastric foveolar metaplasia. As gastric foveolar metaplasia occurs along with a mucosal repair process in the duodenum, mucosal damages underlay the hamartomatous proliferation of Brunner’s glands and eventually resulted in a formation of large polypoid mass in this case.

Pyloric Brunner's gland hamartoma with atypical hyperplasia

Brunner's gland hamartoma (BGH) is an extremely rare benign digestive tumor, generally located in the duodenal bulb. We report the case of a 51-year-old asymptomatic man with a large pedunculated BGH arising from the pylorus. It was successfully removed en bloc by endoscopic resection.