Pyloric gland type adenoma of the gallbladder with squamoid spindle cell metaplasia

Detached pyloric gland adenoma of gallbladder: A case report and review of literature

Key Clinical Message

Vigilant intraoperative inspection is crucial during gallbladder surgery to detect any abnormal tissue including the rare pyloric gland adenomas, which can be easily missed. Thorough examination and removal of unusual lymph nodes or thickened tissues are essential to prevent the risk of malignant transformation and ensure comprehensive patient care.

Abstract

Pyloric gland adenomas are uncommon tumors that can be discovered in various organs such as the stomach, gallbladder, and pancreas. Typically lacking noticeable symptoms, these tumors are categorized into subtypes, with the pyloric variant being the most frequent. The term "intracholecystic papillary-tubular neoplasms (ICPN)" is used to emphasize growth patterns and associated risks. In a discussed case, a detached pyloric gland adenoma was identified incidentally during a cholecystectomy procedure. A 58-year-old obese male presented with upper abdominal pain, nausea, and vomiting. He was diagnosed with early cholecystitis caused by gallstones. Subsequently, during a laparoscopic cholecystectomy, a detached adenoma was discovered. Vigilant screening is crucial, as the identification of gallbladder pyloric gland adenomas is a rare occurrence that might be missed during gallbladder surgery. Any unusual lymph nodes or thickened tissues found in association with the gallbladder ought to be carefully removed, as they could potentially indicate detached gallbladder adenomas with a significant risk of becoming malignant. Failing to consider this possibility may subject the patient to prolonged risks if not meticulously examined.

Pyloric Gland Adenoma of the Esophagus Treated by Endoscopic Submucosal Dissection: A Case Report

A pyloric gland adenoma is a rare neoplasm that occurs most frequently in the stomach and should be removed because of its precancerous potential. Although there have been case reports of pyloric gland adenomas in extragastric areas such as the duodenum, pancreas, and bile duct, esophageal pyloric gland adenoma has never been reported in Korea. Herein, we report a case of esophageal pyloric gland adenoma that was successfully treated by endoscopic submucosal dissection.

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.

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.

Pyloric Gland Adenoma (PGA) of the Gallbladder: A Unique and Distinct Tumor from PGAs of the Stomach, Duodenum, and Pancreas

Twenty-four surgically resected, gallbladder pyloric gland adenomas (GB-PGAs) were examined and their features were compared with the reported features of stomach, duodenum, and pancreatic PGAs to better understand GB-PGAs. Clinical information on background gallbladder lesions and histologic data, including tumor grade, existence of squamoid morules, intratumoral cholesterosis, and intracytoplasmic mucins were collected. Immunohistochemical staining for MUC2, MUC5AC, MUC6, CDX2, pepsinogen I, p53, and MIB-1/nuclear β-catenin were evaluated. Targeted mutational analyses of KRAS exon2, GNAS exon 7, and CTNNB1 exon 3 were conducted. We found that 29.2% of the GB-PGAs were histologically high-grade dysplasias/carcinomas; 70.8% were low grade; and 20.8% and 33.3% contained squamoid morules and intratumoral cholesterosis, respectively. In addition, 45.8% and 54.2% of GB-PGAs were mucin-rich and mucin-poor types, respectively. Immunohistochemically, MUC6 was diffusely positive in all GB-PGAs; MUC2, MUC5AC, and CDX2 were only focally positive, and no pepsinogen-I positive cells were observed. Nuclear β-catenin accumulation was observed in all cases; however, the ratio varied among cases. Mucin-poor types were significantly associated with high histologic grade dysplasias/carcinomas and high nuclear β-catenin labeling indices. Mutational analyses identified CTNNB1 mutations in 100% of GB-PGAs (21/21), KRAS in 4.2% (1/23), and GNAS in 0% (0/22). The present study clarified the unique histologic features, phenotypic differentiation, and molecular statuses frequently associated with GB-PGAs. Altogether, our data suggest that tumorigenesis of GB-PGA is distinct from that of stomach, duodenum, and pancreatic PGAs.

Gastric pyloric gland adenoma: a multicentre clinicopathological study of 67 cases

AIMS

There is limited information regarding the clinicopathological and immunohistochemical characteristics of gastric pyloric gland adenomas (PGAs).

METHODS AND RESULTS

Sixty-seven cases of gastric PGA from 57 patients were analysed. PGAs occurred with similar frequency in men and women (47.4 and 52.6%, respectively), with a mean age of 66 years. Most presented in the gastric body/fundus (67.2%). Fifteen cases (22.4%) developed against a background of autoimmune gastritis (AIG), whereas normal mucosa was seen in 35.8%. Only 16.4% (11 cases) developed in patients with a genetic predisposition, most commonly familial adenomatous polyposis. Low-grade lesions had a mean size of 1.5 cm, while PGAs with high-grade dysplasia (HGD) or adenocarcinoma had a mean size of 3.5 cm (P < 0.001) and more commonly showed tubulovillous architecture (50.0 versus 25.6% in low-grade dysplasia; P = 0.040). Most PGAs (61.2%) co-expressed mucin (MUC)5AC and MUC6 (mixed type), which was associated significantly with HGD or adenocarcinoma (P = 0.013). AIG was also associated with HGD (P = 0.027), but genetic predisposition did not correlate with the grade of dysplasia (P = 0.793). The recurrence rate of PGA was similar for high- (11.8%) and low-grade lesions (7.4%) (P = 0.624).

CONCLUSIONS

The risk of HGD increases with the size of PGA, tubulovillous architecture and the presence of AIG as well as mixed immunophenotype. As the overall local recurrence rate is less than 10%, PGAs may be treated conservatively, but they should be excised completely if possible, particularly if they are large or show high-grade features.

Gastric pyloric gland adenoma

Pyloric gland adenomas are rare neoplasms of the gastrointestinal tract. Gastric pyloric gland adenomas have been shown to arise in chronically damaged mucosa. The neoplastic glands have gastric pyloric gland differentiation and have a tightly packed organization with occasional cystic dilatation. The individual cells are cuboidal to columnar, with eosinophilic to amphophilic cytoplasm and either no apical mucin cap or a poorly formed apical mucin cap. The nuclei are round to oval, with occasional prominent nucleoli. Immunohistochemically, the neoplastic cells label with markers of gastric pyloric gland differentiation, including MUC6 and MUC5AC. There is limited information regarding the natural history of pyloric gland adenomas, but clinical series have described adenocarcinomas in association with gastric pyloric gland adenomas. The ideal clinical management is adequate sampling of the lesion to investigate for high-grade dysplasia and/or invasive cancer and recommendation to clinical colleagues to investigate the background mucosa for the etiology of chronic gastritis as well as potential additional neoplastic lesions. This review will focus on gastric pyloric gland adenomas.

Pyloric gland adenoma of the cystic duct with malignant transformation: report of a case with a review of the literature

Background

Pyloric gland adenoma consists of closely packed pyloric-type glands lined by mucus-secreting cells. To date, approximately 230 cases have been reported, mostly of gastric localization with a tumour size up to 3.5 cm and a mean age of occurrence around 70 years. Adenocarcinoma develops in about 40% of cases and may be difficult to detect due to relatively mild nuclear atypia.

Case presentation

We present the first case of a pyloric gland adenoma of the cystic duct in a 62-year-old male patient and demonstrate the clinicopathologic characteristics, including radiographic, molecular, and cytogenetic findings. The 2 cm-tumour developed in the cystic duct and protruded into the hepatic and common bile duct. On microscopic examination, it displayed closely packed pyloric-type glands, and focal architectural distortion with mild nuclear atypia. Immunohistochemically, it expressed MUC1, MUC5AC, MUC6 and p53, but not MUC2 and CD10. The Ki67-proliferation index was 25%. Furthermore, high-grade intraepithelial neoplasia was observed in the surrounding bile duct. We detected chromosomal gains at 7p, 7q11q21, 15q, 16p, 20, losses at 6p23pter, 6q, 18, and amplifications at 1q and 6p21p22 in the pyloric gland adenoma by comparative genomic hybridization. A KRAS codon 12 mutation (c.35G>T; p.G12V) was detected in the pyloric gland adenoma and in the adjacent dysplasia by sequencing analysis. The diagnosis of pyloric gland adenoma was established with transition into well-differentiated adenocarcinoma and high-grade biliary intraepithelial neoplasia.

Conclusion

Pyloric gland adenoma evolving in the cystic duct is a rare differential diagnosis of obstructive bile duct tumours. Other premalignant bile duct lesions may be associated. Due to the risk of developing adenocarcinoma, surgical resection should be performed.

Adenomas of the gallbladder. Morphologic features, expression of gastric and intestinal mucins, and incidence of high-grade dysplasia/carcinoma in situ and invasive carcinoma

We report 201 gallbladder adenomas from 91 patients most of whom were adult females. Fifty-three (58%) patients had gallstones. In 83 (91%) patients the adenomas were single. One gallbladder had 102 adenomas. Histologically, 165 (82%) of 201 adenomas were classified as pyloric, 28 (14%) as intestinal, 5 (2.4%) as foveolar, and 3 (1.4%) as biliary. Two patients had intestinal-type adenomas coexisting with biliary papillomatosis. Twenty-eight percent of pyloric gland adenomas contained squamoid morules. Two pyloric gland adenomas were composed predominantly of columnar oxyphil cells. High-grade dysplasia/carcinoma in situ was identified in 44 (27%) of 165 pyloric gland adenomas and low-grade dysplasia in 25 (15%) of 165. However, only 2 (1%) invasive adenocarcinomas, both of intestinal type, arose in pyloric gland adenomas. Both patients survived more than 5 years. Intestinal-type adenomas were classified as tubular, papillary, and tubulopapillary. High-grade dysplasia/carcinoma in situ was recognized in 13 (46%) of 28 intestinal adenomas. However, only 1 (3.5%) invasive adenocarcinoma with biliary phenotype arose in an intestinal-type adenoma. Foveolar adenomas showed low-grade dysplasia, and biliary adenomas were composed of columnar cells similar to the normal biliary cells of the gallbladder. None of these tumors progressed to adenocarcinoma. MUC5AC and MUC6 labeled 44 (95%) of 46 pyloric gland adenomas, whereas CDX2 was positive in 14 (78%) of 18 intestinal adenomas and MUC2 in 6 (33%) of 18. MUC5AC and MUC6 labeled 2 foveolar adenomas, and 2 biliary adenomas expressed only CK7. The immunophenotype of gallbladder adenomas justifies their classification into pyloric, intestinal, foveolar, and biliary. Our results indicate that adenomas of the gallbladder play a minor role in the pathway of gallbladder carcinogenesis.

Immunohistochemical analysis of pyloric gland adenomas using a series of Mucin 2, Mucin 5AC, Mucin 6, CD10, Ki67 and p53

A pyloric gland adenoma (PGA) of the stomach was first described in a book chapter in 1976 by Kurt Elster and has been rarely reported in the literature. We expanded the current immunohistochemical data of these adenomas in a detailed series to further analyse the immunhistochemical status of PGA. From 60 patients with PGA with and without adenocarcinomas of the gastrointestinal tract, an immunhistochemical panel of Mucin 2, Mucin 5AC, Mucin 6, CD10, Ki67 and p53 was used to define the expression of these markers. All PGA were positive for Mucin 6 (deep mucoid glands), which they express over the whole lesion up to the surface. Mucin 5AC expression varies from case to case. A transition from gastric to intestinal differentiation can be observed focally as depicted by Mucin 2 and CD10 in 65% of the cases. The gastric corpus mucosa of elderly patients with either Helicobacter pylori gastritis or autoimmune gastritis is highly affected. Almost 47% of all PGA already underwent malignant transformation into adenocarcinoma. Significant immunohistochemical differences could be detected between PGA with and without adenocarcinoma regarding ki67 and p53. The diagnosis of PGA can be confirmed immunohistochemically by staining against apomucin 6 and apomucin 5AC. Focal intestinal differentiation supports the hypothesis that gastric adenocarcinomas can initially develop from carcinomas of the gastric type and transform into intestinal type later on. The high frequency of malignant transformation of PGA underlines its high potential for invasive malignancy.

[Tubular adenoma of the stomach with special reference to the Japanese criteria and pyloric gland adenoma]

The term gastric adenoma usually refers to a flat adenoma of the intestinal type. Adenomas of the gastric type, so-called pyloric gland adenomas (PGA), which was first characterized by German and Japanese pathologists in 1990, have been regarded as exceptional until recently. In 2003, we first reported systematic clinical pathological analyses of PGA, demonstrating its unstable and precancerous nature. American gastrointestinal pathologists have finally recognized this disease entity in 2009. In this article we introduce the Japanese criteria of the gastric adenoma and review and discuss the clinical pathological and molecular aspects of PGAs.

Pyloric gland adenoma: an entity distinct from gastric foveolar type adenoma

Pyloric gland adenoma (PGA) is a rare neoplasm demonstrating gastric epithelial differentiation. In this series, we studied 41 PGAs from 36 patients. We compared them to 28 gastric foveolar type gastric adenomas (GTAs) from 25 patients. PGAs occurred in an older population with a mean age of 73 compared with 48 in GTAs (P<0.001). There was a significant female predominance, particularly for gastric PGAs. Morphologically, PGAs were characterized by closely packed pyloric gland-type tubules with a monolayer of cuboidal to low columnar epithelial cells containing round nuclei and pale to eosinophilic cytoplasm with a ground glass appearance. The cells lacked an apical mucin cap, a feature distinct from GTAs. An immunohistochemical panel of mucin core peptides (MUCs) and CDX2 was performed on a subset of the lesions. All PGAs expressed MUC6 with coexpression of MUC5AC, whereas GTAs expressed predominantly MUC5AC without MUC6. Both lesions lacked CDX2 and MUC2 except in areas of intestinal metaplasia (IM) found in some PGAs. Histologic features consistent with conventional dysplasia were found in 26 (63.4%) PGAs. Using a 2-tier grading system, 5 (12.2%) cases demonstrated low-grade dysplasia whereas 21 (51.2%) cases showed high-grade dysplasia including 5 (12.2%) cases with an associated intramucosal or more deeply invasive adenocarcinoma. This was significantly different from GTAs; all cases showed only low-grade dysplasia (P<0.001). In addition, 60% of gastric PGAs were associated with IM in the surrounding mucosa and 40% of lesions arose in a background of autoimmune gastritis, whereas these 2 conditions were only associated with 1 case (3%) of GTA. In summary, PGA is a distinct entity. Despite its bland histologic appearance, it is much more likely to be accompanied by background IM and autoimmune gastritis and can evolve into invasive adenocarcinoma displaying pyloric gland differentiation.

Gastric-type well-differentiated adenocarcinoma and pyloric gland adenoma of the stomach

Since 1985, when gastric-type well-differentiated adenocarcinomas were demonstrated in hyperplastic polyps of the stomach, we have studied phenotypic expression in gastrointestinal epithelial lesions. The recent discovery of MUC genes coding core proteins of mucin has improved research on the phenotypic expression of gastrointestinal neoplasms. The disease entity of gastric-type well-differentiated adenocarcinoma has recently been accepted, especially in Japan and Europe. This entity has often become a clinicopathological subject of discussion, because its biological behavior is possibly highly malignant, in spite of the difficulty in making endoscopic and histopathological diagnoses. Even under these circumstances, the term "gastric adenoma" usually means flat adenoma of the intestinal type. Gastric-type adenomas have been regarded as exceptional until recently. Although gastric-type adenomas could theoretically be classified into foveolar type and pyloric-gland type, foveolar-type adenoma is, in practice, difficult to distinguish from gastric-foveolar-type adenocarcinoma. In 2003, we first reported systematic clinicopathological analyses of pyloric gland adenoma, demonstrating its unstable and precancerous nature. In this article, we review and discuss the clinicopathological and molecular pathological aspects of gastric-type well-differentiated adenocarcinomas and pyloric gland adenomas, mainly based on our published and unpublished data.

Pyloric gland adenoma arising in Barrett's esophagus with mucin immunohistochemical and molecular cytogenetic evaluation

Pyloric gland adenoma is a recently described and very rare entity. The occurrence of adenoma is very unusual in Barrett's epithelium of the esophagus. We report a case of esophageal polyp showing the features of pyloric gland adenoma, which was surrounded by so-called specialized columnar epithelium. Immunohistochemically, most tumor glands were strongly positive for MUC6, except in the superficial layer. MUC5AC was positive in almost all tumor cells, but MUC2 and CD10 were negative in the tumor. MIB-1-positive proliferating cells were distributed throughout the tumor. Microdissection and comparative genomic hybridization analyses revealed losses on 2p24-25.2, 2q14.1-ter, 5q31.3-32, 6q23-24, 8q23-24.2, 11q22.3-24 and 18q21.1-22. This is the first case of pyloric gland adenoma found to arise in Barrett's epithelium of the esophagus, showing its unstable and precancerous nature.

Adenoma with gastric differentiation (so-called pyloric gland adenoma) in a heterotopic gastric corpus mucosa in the rectum

In a 46-year-old man, a pedunculated rectal polyp measuring 3.0x3.0x2.0 cm was diagnosed histologically as a pyloric gland-type adenoma arising in heterotopic gastric corpus mucosa. The luminal site was covered by glands of the gastric foveolar type, displaying focal marked proliferation interpreted as low-grade intraepithelial neoplasia. A bidirectional gastric differentiation was found: most lower glandular structures showed positivity for the deep gastric mucin core protein Muc 6 and superficial positivity for gastric foveolar epithelium mucin core protein Muc 5AC. Pyloric gland adenoma has so far been described in one larger series only and a few case reports of the stomach, gallbladder, pancreatic duct and within heterotopic gastric corpus mucosa of the duodenal bulb. The present case report is the first case of a pyloric gland-type adenoma within a gastric corpus heterotopia of the rectal mucosa.

Pyloric gland adenoma: a clinico-pathological analysis of 90 cases

BACKGROUND

Pyloric gland adenoma is a rarely described neoplasia of the gastric mucosa. Recent publications have shown that similar lesions are also found in the gallbladder, the main pancreatic duct, the duodenum and the cervix of the uterus. Apart from case reports, few clinical data are available on these patients. We therefore conducted a search of the archived material collected between 1990 and 2000 for more clinical data on patients with this rare lesion.

PATIENTS AND METHODS

Between 1990 and 2000, 90 patients were diagnosed as having a pyloric gland adenoma in the stomach (77 patients), duodenal bulb (7 patients), duodenum (1 patient), bile duct (3 patients) or gallbladder (2 patients).

RESULTS

Pyloric gland adenomas account for 2.7% of all gastric polyps and occur predominantly in old age (73+/-12.8 years), more frequently in women (75%) than in men. The predilection site in the stomach is the corpus mucosa (64%) and they are often found in patients suffering from autoimmune gastritis (36%). At the time of diagnosis, pyloric gland adenomas measure 16.1+/-9.1 mm in size. In 30% of gastric pyloric adenomas, transition to well-differentiated adenocarcinoma has been noted.

DISCUSSION

In our material, pyloric gland adenoma is the third most common neoplastic polypoid lesion in the stomach. Since a search through the literature revealed only a few case reports on this lesion, it is possible that for some reason this lesion might be diagnosed more often than reported.

CONCLUSION

Our study revealed that 30% of the gastric pyloric gland adenomas showed continuous transition to well-differentiated adenocarcinoma at the time of the initial diagnosis. This underscores the malignant potential of the lesion, and the need for polypectomy.