Oxyntic gland neoplasm of the stomach: expanding the spectrum and proposal of terminology

An emerging entity of gastric adenocarcinoma: clinicopathological features and differential diagnosis of gastric adenocarcinoma of fundic-gland type in 25 retrospective cases

Gastric adenocarcinoma of fundic-gland type (GA-FG) is a rare gastric cancer with an extremely low rate of vascular and lymph node metastases. It can be cured with endoscopic submucosal dissection (ESD). However, inadequate understanding of GA-FG may lead to overtreatment, negatively impacting patient quality of life. We analyzed the clinical, endoscopic, and pathological characteristics of 25 cases of GA-FG. Immunohistochemical markers (CEA, MUC2, MUC5AC, MUC6, H + /K + ATPase, Pepsinogen-I, CgA, P53, and Ki67) were used to differentiate GA-FG from conventional gastric adenocarcinoma (CGA), neuroendocrine tumor (NET), gastric adenocarcinoma of fundic-gland mucosa type (GA-FGM), and other related conditions. The expression of β-catenin and Yes-associated protein (YAP) was also analyzed. All 25 GA-FG cases were located in the proximal stomach, with maximum diameter ranging from 4 to 20 mm. Histologically, the tumors displayed branching, mutual pulling or fusion of glandular duct structures, occasional sieve-like patterns, and mild cellular atypia. Some cases exhibited foveolar hyperplasia, with indistinct boundaries between proliferating and normal epithelium. The absence of an abrupt transition at low magnification was a critical feature to distinguish GA-FG from GA-FGM. Immunophenotypically, GA-FG resembled gastric-type adenocarcinoma with a low Ki67 index. The wild-type expression of P53 and varying Ki67 intensity patterns were helpful for diagnosing non-neoplastic hyperplasia. Abnormal β-catenin nuclear expression was found in 1 case, while 6 out of 12 showed positive YAP expression. GA-FG is a well-differentiated adenocarcinoma mimicking gastric fundic glands growth patterns. Accurate diagnosis of GA-FG is essential to accurate treatment and avoid oversurgery.

Contract to kill: GNAS mutation

The mutation in Gsα-coding GNAS exons, popular as gsp oncogene, is the most frequent mutation across all heterotrimeric G proteins involved in oncogenesis. GNAS R201, the most frequently mutated, followed by Q227, are found predominantly across various neoplasms and cancers such as IPMN, pituitary, thyroid, appendiceal, colorectal, etc. This review emphasizes the pivotal significance of the gsp oncogene and its ramifications underpinning the sustained addiction to GNAS mutation. Recent studies delineating the mechanistic intricacies that provide solid evidence of the profound impact of oncogenic GNAS on tumor formation, progression, and maintenance are highlighted. We have leveraged the discoveries of Gsα as an ideal neoantigen candidate for vaccine therapy, allele-specific inhibitors, and cyclic peptide-based small molecular inhibitors for G proteins and explored the therapeutic potential to target oncogenic GNAS directly. Alternative therapeutic modalities and patient-centric studies to mitigate the impact of GNAS mutations are also discussed. The exposition of novel studies and strategies designed to address the potential challenges inherent in these approaches of targeting the activating mutations of GNAS, along with probable avenues for further investigation, are highlighted. This review aims to reverberate the current understanding of the oncogenic potential of GNAS, the genomic and biological landscape of GNAS-driven neoplasms and cancers, and potential therapeutic strategies against them.

Diffuse Cyclin D1 and SPINK1 Expression in Gastric Oxyntic Gland Neoplasms: Promising Diagnostic Markers Identified Using Spatial Transcriptome Analysis

Oxyntic gland neoplasms typically arise in Helicobacter pylori-naive stomachs and are composed predominantly of chief cells, with a smaller component of parietal cells. Their pathologic diagnosis can be challenging owing to minimal cellular atypia. Especially in biopsy specimens with a limited tumor volume or when pathologists have limited experience in diagnosing this neoplasm, distinguishing them from normal oxyntic glands can be difficult, and no reliable diagnostic markers are currently available. In this study, single-cell spatial transcriptome analysis successfully identified significant upregulation of CCND1 and SPINK1 in all 6 analyzed cases of oxyntic gland neoplasms compared with normal oxyntic glands. Immunohistochemical analysis confirmed this finding in 21 endoscopically resected cases of oxyntic gland neoplasms, demonstrating that cyclin D1 and serine peptidase inhibitor Kazal type 1 (SPINK1) were diffusely expressed in oxyntic gland neoplasms, whereas their expression was scarcely observed in normal oxyntic glands, with a few of them showing weak to moderate staining. Even in biopsy specimens, these 2 markers highlighted the tumor areas and clearly distinguished neoplastic from normal oxyntic glands. Nonneoplastic foveolar epithelia and mucous neck cells also showed positive staining for both cyclin D1 and SPINK1. In addition, a mild increase in cyclin D1 expression and patchy or mosaic expression of SPINK1 were observed in fundic gland polyps, H. pylori-associated gastritis, and pyloric gland adenomas, whereas a diffuse staining pattern was specific to oxyntic gland neoplasms. These observations suggest that cyclin D1 and SPINK1 are reliable markers in differentiating oxyntic gland neoplasms from nonneoplastic oxyntic glands and pyloric gland adenomas. Cyclin D1 is commonly used for immunostaining in many pathology departments, and owing to its higher sensitivity and specificity compared with SPINK1, it is considered the best diagnostic marker.

Spectrum of gastric neoplasms in Helicobacter pylori-naïve patients

Chronic Helicobacter pylori (Hp) infection is the largest etiological factor for gastric cancer, but in recent years the reports of Hp-naïve gastric neoplasms (HpNGNs) have increased as the Hp-infected population in Japan has been declining. The histopathologic spectrum of HpNGNs differs significantly from that of conventional Hp-infected gastric neoplasms. Molecularly, the former harbor considerably fewer genetic and epigenetic abnormalities, reflecting the absence of chronic inflammatory conditions in the gastric mucosa. The majority of HpNGNs fall within several specific histological entities; each arise from particular background mucosa. Most originate from the fundic gland mucosa and have a gastric immunophenotype, as seen in foveolar-type gastric adenoma (FGA), oxyntic gland adenoma (OGA)/gastric adenocarcinoma of fundic gland type (GA-FG), signet-ring cell carcinoma (SRCC), and sporadic fundic gland polyp with dysplasia (FGPD). In contrast, tumors arising from the pyloric or cardiac gland mucosa have a diverse immunophenotype, as seen in intestinal-type gastric dysplasia (IGD) and gastric cardiac carcinoma. FGA, FGPD, SRCC, and IGD are mostly found as small intramucosal lesions. OGA/GA-FG frequently progresses to invasive carcinoma, but only a few have lymph node metastases. Thus, these tumors are regarded as precancerous lesions by Western pathologists, while in Japan they tend to be diagnosed as carcinomas, even in cases of low-grade dysplasia. Gastric cardiac carcinomas, on the other hand, are often found as advanced carcinomas and harbor a high malignant biological potential. A new diagnostic framework for gastric neoplasms is required in the present era of Hp-naïve individuals in Japan.

Successful Endoscopic Management of Oxyntic Gland Adenoma: A Case Report

Oxyntic gland adenomas (OGAs) are benign gastric neoplasms composed of gland-forming epithelial cells with predominantly chief cell differentiation resembling oxyntic glands confined to the mucosa. If the tumor has submucosal invasion, it should be classified as gastric adenocarcinoma of fundic gland type. The OGAs can pose a diagnostic challenge, as they can resemble aggressive gastric neoplasms. There are no current guidelines on the management of OGA. Due to the relatively small size and low malignant potential, these lesions are typically managed endoscopically. In this case, we are reporting a 22-year-old woman who was diagnosed with OGA during evaluation of iron deficiency anemia and underwent successful endoscopic resection.

Oxyntic Gland Neoplasms - From Adenoma to Advanced Gastric Cancer: A Review of 29 Cases

PURPOSE

Oxyntic gland neoplasm (OGN) is a rare condition that can be classified as oxyntic gland adenoma (OGA) or gastric adenocarcinoma of fundic-gland type (GA-FG). GA-FG primarily presents as early gastric cancer, with only a few reported cases of advanced gastric cancer (AGC). We aimed to investigate the clinicopathological features of OGN and describe an aggressive variant.

MATERIALS AND METHODS

We investigated a total of 29 cases, including a patient with double primary cases, diagnosed with OGN or differentiated-type adenocarcinoma with GA-FG morphology, between November 2016 and April 2022. We analyzed 54 pathological specimens and reviewed their clinicopathological, endoscopic, and histological features. The lesions were reclassified as OGA or GA-FG, and immunohistochemical (IHC) staining for MUC-5AC and MUC-6 was performed on available resected GA-FG cases.

RESULTS

The median patient age was 65 years and males accounted for 58.6% of patients. Most cases occurred in the body horizontally (69.0%) and on the greater curvature side cross-sectionally (48.3%). Endoscopically, type 0-IIa (41.4%) and a subepithelial tumor-like appearance (24.1%) were the most common findings. Histologically, there were 8 cases of OGA (27.6%) and 21 cases of GA-FG (72.4%). In GA-FG, MUC-6 was positive in 13 cases (81.3%), whereas MUC-5AC was positive in 8 cases (50.0%). Three cases presented as AGCs.

CONCLUSIONS

Although OGNs are generally considered low-grade, they can present as AGCs and may exhibit features of lymphovascular or perineural invasion. Recognizing the clinicopathological features and accurately diagnosing OGN are important for providing adequate treatment.

Antacids and reflux esophagitis as a risk factor for gastric neoplasm of fundic-gland type: A retrospective, matched case-control study

BACKGROUND AND AIM

Since the first report of gastric adenocarcinoma of the fundic-gland type in 2010, the clinicopathological characteristics of gastric neoplasm of the fundic-gland type (GNFG) have become clearer; however, their risk factors remain unclear. This exploratory study aimed to identify the risk factors for GNFG.

METHODS

We conducted a single-center, retrospective, matched case-control study using medical information recorded at our health management center from January 2014 to July 2023. During this period, 39 240 people underwent upper gastrointestinal endoscopy. GNFG were extracted as cases and matched to controls, according to age and sex, in a 1:8 ratio, excluding those with a history of gastrointestinal surgery and those with a history or comorbidity of cancer. Univariate analysis was used to compare patient background and endoscopic findings. Multivariable analysis was performed, adjusting for factors with P values < 0.1 and antacid use.

RESULTS

A total of 20 GNFG cases and 160 matched healthy controls were included. In the univariate analysis, only reflux esophagitis was significantly more common in GNFG (40.0% vs 18.1%; P = 0.036). Factors antacids and duodenitis had P values < 0.1. Logistic regression analysis was performed, adjusting for antacids, reflux esophagitis, and duodenitis. Antacids and reflux esophagitis were the independent risk factors for GNFG (odds ratio = 3.68 [95% confidence interval: 1.04-11.91] and 3.25 [95% confidence interval: 1.11-9.35]).

CONCLUSIONS

Although the sample of patients with GNFG was small, antacids and reflux esophagitis were identified as a risk factor. The pathogenesis of antacids and reflux esophagitis may be involved in the development of GNFG.

[Oxyntic gland neoplasia - case report and diagnostic dilemma]

Az oxynticus mirigy neoplasia terminológia a gyomor olyan atípusos fő- és fedősejtek által alkotott mirigyei esetében használatos, amikor nem látszik invázió, tehát a fundus mirigy adenocarcinoma diagnózisa nem állítható fel, ugyanakkor a laesio nem került kompletten eltávolításra, tehát teljes vastagsága nem vizsgálható. Az oxynticus mirigy neoplasiák etiológiája jelenleg tisztázatlan, egyes források protonpumpagátlókkal, valamint antihisztamin-használattal hozták őket összefüggésbe. Endoszkópos vizsgálat során a morfológiájuk nem specifikus, lapos és polypoid laesiók egyaránt lehetnek, és döntően a gyomor felső egyharmadára lokalizáltak. Amennyiben komplett endoszkópos nyálkahártya-reszekció kivitelezhető, további kezelés nem szükséges, tehát összességében jó prognózisú elváltozásoknak tarthatók. Közleményünkben egy 84 éves nő esetét mutatjuk be, akinél haspuffadás miatt indult kivizsgálás, és gasztroszkópia történt. A corpus területén 1 cm-es, lapos polypus volt látható, melyből többszörös biopszia történt, a képlet közel teljes eltávolításával. A szövettani vizsgálat során a nyálkahártya mélyén jól körülírt és jól differenciált, expanzív szélű elváltozás volt megfigyelhető, melyet atípusos fősejtek, elvétve pedig fedősejtek alkottak. Ezek a sejtek oxynticusmirigy-szerű struktúrákat képeztek. A pepszinogénreakció a fősejtekben szemcsés jellegű, citoplazmatikus pozitivitást mutatott. H+/K+ ATPáz reakcióval a fedősejtekben szintén szemcsés jellegű, citoplazmatikus pozitivitás látszott. MUC6-tal a laesionalis sejtekben diffúz, citoplazmatikus pozitivitás volt megfigyelhető. Invázió jeleit nem láttuk. A morfológiai, valamint az immunfenotípus alapján is az elváltozást oxynticus mirigy neoplasiának véleményeztük, ’low-grade’ dysplasiával. Az oxynticus mirigy neoplasiák mind klinikai, mint patológiai szempontból fokozott figyelmet igényelnek, ugyanis ritka entitásokról van szó, melyeknek egyelőre sem az etiológiájuk, sem a prognózisuk nem tisztázott teljes mértékben. Differenciáldiagnosztikai szempontból fundus mirigy polypus, pylorus mirigy adenoma, valamint neuroendokrin tumor jön szóba. A definitív diagnózis felállítását pepszinogén, H+/K+ ATPáz, valamint MUC6 immunhisztokémiai reakciók segíthetik. Orv Hetil. 2024; 165(27): 1053–1057.

Gastric epithelial neoplasm of fundic-gland mucosa lineage: representative of the low atypia differentiated gastric tumor and Ki67 may help in their identification

Background

Gastric epithelial neoplasm of the fundic-gland mucosa lineages (GEN-FGMLs) are rare forms of gastric tumors that encompass oxyntic gland adenoma (OGA), gastric adenocarcinoma of the fundic-gland type (GA-FG), and gastric adenocarcinoma of the fundic-gland mucosa type (GA-FGM). There is no consensus on the cause, classification, and clinicopathological features of GEN-FGMLs, and misdiagnosis is common because of similarities in symptoms.

Methods

37 cases diagnosed with GEN-FGMLs were included in this study. H&E-stained slides were reviewed and clinicopathological parameters were recorded. Immunohistochemical staining was conducted for MUC2, MUC5AC, MUC6, CD10, CD56, synaptophysin, chromograninA, p53, Ki67, pepsinogen-I, H+/K+-ATPase and Desmin.

Results

The patients' ages ranged from 42 to 79 years, with a median age of 60. 17 were male and 20 were female. Morphologically, 19 OGAs, 16 GA-FGs, and two GA-FGMs were identified. Histopathological similarities exist between OGA, GA-FG, and GA-FGM. The tumors demonstrated well-formed glands, expanding with dense growth patterns comprising pale, blue-grey columnar cells with mild nuclear atypia. These cells resembled fundic gland cells. None of the OGA invaded the submucosal layer. The normal gastric pit epithelium covered the entire surface of the OGA and GA-FG, but the dysplasia pit epithelium covered the GA-FGM. Non-atrophic gastritis was observed in more than half of the background mucosa. All cases were diffusely positive for MUC6 and pepsinogen-I on immunohistochemistry. H+/K+-ATPase staining was negative or showed a scattered pattern in most cases. MUC5AC was expressed on the surface of GA-FGMs. p53 was focally expressed and the Ki67 index was low (1%-20%). Compared with OGA, GA-FG and GA-FGM were more prominent in the macroscopic view (p < 0.05) and had larger sizes (p < 0.0001). Additionally, GA-FG and GA-FGM exhibited higher Ki67 indices than OGA (p < 0.0001). Specimens with Ki-67 proliferation indices >2.5% and size >4.5 mm are more likely to be diagnosed with GA-FG and GA-FGM than OGA.

Conclusion

GEN-FGMLs are group of well-differentiated gastric tumors with favourable biological behaviours, low cellular atypia, and low proliferation. Immunohistochemistry is critical for confirming diagnosis. Compared with OGA, GA-FG and GA-FGM have larger sizes and higher Ki67 proliferation indices, indicating that they play a critical role in the identification of GEN-FGML. Pathologists and endoscopists should be cautious to prevent misdiagnosis and overtreatment, especially in biopsy specimens.

Prevalence, clinical characteristics and treatment outcomes of oxyntic gland neoplasm: a single-center retrospective study

BACKGROUND

Oxyntic gland neoplasm (OGN) is a rare subtype of gastric cancer. The aim of this study is to evaluate the prevalence, clinicopathological features, effectiveness and safety of endoscopic treatment, as well as the prognosis of OGN.

METHODS

We retrospectively analyzed the data of patients pathologically diagnosed with OGN at our hospital from November 1, 2019 to May 1, 2023.

RESULTS

A total of 36 patients with 45 lesions were identified, resulting in a disease frequency of 0.047% (36/76,832). The mean age was 55.0 ± 7.5 years, with a male-to-female ratio of about 1:1.12. Most lesions were ≤10 mm in size (84.4%), located in the upper third of the stomach (73.3%), exhibited slight elevation (75.5%), appeared whitish (55%), had dilated blood vessels on the surface (75.5%). 16 and 21 lesions were treated by precutting endoscopic mucosal resection (EMR-P) and endoscopic submucosal dissection (ESD), respectively. No significant differences were found between EMR-P and ESD in terms of en bloc resection rate (100% vs 100%, p = 1.000), complete resection rate (100% vs 90.5%, p = 0.495), and curative resection rate (93.8% vs 90.5%, p = 1.000). No complications such as bleeding and perforation were observed. No recurrence or metastasis was observed during the follow-up period.

CONCLUSIONS

OGN is a rare tumor with unique clinical, endoscopic, and pathological characteristics. EMR-P and ESD are deemed safe and effective for treating OGNs. The relatively faster and easier EMR-P seems at least non-inferior to ESD, especially for removal of smaller OGNs. The overall prognosis is favorable.

A case of gastric adenocarcinoma with pyloric gland-type infiltrating submucosa

BACKGROUND

The development of immunohistochemical staining has revealed that gastric adenocarcinoma with the gastric phenotype can be divided into the foveolar, fundic gland, and pyloric gland phenotypes. Gastric adenocarcinoma of the pyloric gland type is difficult to diagnose using biopsy because of its low atypia and rarity. Herein, we describe a case of gastric adenocarcinoma of the pyloric gland type that was diagnosed immunohistochemically after endoscopic resection.

CASE PRESENTATION

A 67-year-old man was referred to our hospital for the diagnosis and treatment of a 30-mm elevated lesion on the lesser curvature side of the middle of the gastric body. Although four biopsies were performed, it was difficult to determine whether the lesion was benign or malignant. Therefore, endoscopic submucosal dissection was performed, and the presence of tumor cells infiltrating the submucosa with venous invasions was identified. Immunohistochemical staining revealed that the tumor cells were positive for MUC5AC and MUC6 and negative for Pepsinogen I and H + /K + -ATPase. From the above findings, he was diagnosed as having gastric adenocarcinoma with pyloric gland type. The patient underwent a laparoscopic distal gastrectomy and was discharged without any adverse events.

CONCLUSIONS

Gastric adenocarcinoma of the pyloric gland type is a rare disease, and endoscopic resection can serve as a viable diagnostic option for this condition when it is difficult to diagnose using biopsy. Immunohistochemical pathology images can aid in the diagnosis of gastric adenocarcinoma of the pyloric gland type.

Comparison of Prognosis and Metachronous Gastric Tumor Rates After Endoscopic Submucosal Dissection Between Gastric Neoplasm of Fundic Gland Type Neoplasms and Conventional Gastric Adenocarcinoma

INTRODUCTION

Gastric neoplasm of the fundic gland type (GNFG) is a tumor with a good prognosis. However, since it has not been compared with conventional gastric adenocarcinoma (CGA), it is unknown whether it has a good prognosis or requires surveillance after treatment. The purpose of this study was to determine the prognosis and metachronous gastric tumor rates compared with those of CGA.

METHODS

We conducted a single-center, retrospective, matched-cohort study using our database from January 2010 to December 2021. We extracted GNFG data from the endoscopic submucosal dissection (ESD) database and matched patients with conventional early gastric cancer as controls in a 1:4 ratio by age and sex. GNFG and CGA were compared for the overall survival (OS), disease-specific survival, progression-free survival, and metachronous gastric tumor rates.

RESULTS

Overall, 43 lesions were GNFG and 164 CGAs were matched. There were three deaths in the GNFG group and 11 deaths in the CGA group. There was no significant difference in the OS between the two groups (P=0.81). The five-year OS rates for the GNFG and CGA groups were 90.9% and 92.9%, respectively. No disease-specific deaths or recurrences were observed in either group. There was no significant difference in the cumulative metachronous gastric tumor rate between the two groups (P=0.17). The cumulative five-year metachronous gastric tumor rates for the GNFG and CGA groups were 6.6% and 2.5%, respectively.

CONCLUSIONS

The prognosis for GNFG is good, however, not better than that for CGA. The metachronous gastric tumor rate after ESD in GNFG was not lower than that in CGA. Therefore, after ESD, GNFG may need to be managed in the same way as CGA.

Pathology and Clinical Relevance of Gastric Epithelial Dysplasia

Gastric dysplasia is defined as an unequivocally neoplastic epithelium. Dysplastic lesions are characterized by cellular atypia reflective of abnormal differentiation and disorganized glandular architecture. The last few years have been marked by a refinement of the prognosis and risk of progression of gastric dysplasia and the recognition of novel morphologic patterns of dysplasia. Determination of the correct diagnosis and grade of dysplasia are critical steps since it will be predicting the risk of malignant transformation and help tailor appropriate surveillance strategy. This review describes the morphologic characteristics of conventional dysplasia and nonconventional gastric dysplasia that have been more recently characterized.

Gastric adenocarcinoma of the fundic gland type: A review of the literature

Background and Aim

Gastric adenocarcinoma of the fundic gland type (GA-FG) is a newly described tumor entity but lacking consensus. This review summarizes the key features and controversies regarding this uncommon neoplasm.

Methods

We reviewed studies on GA-FG published in English from 2007 to 2021.

Results

We found that 327 cases (340 lesions) have been reported. GA-FG lesions originate from deep layers of the gastric mucosa, with the following characteristics on conventional white-light endoscopy examination. These lesions, macroscopically identified as submucosal tumor-like 0-IIa, tend to have a whitish discoloration without inflammation, atrophy, or intestinal metaplasia in the background mucosa. Tumors located in the upper third of the stomach are usually solitary, with an average size <10 mm. Contrastingly, magnifying endoscopy with narrow-band imaging mostly shows the absence of any demarcation line, with a regular microvascular pattern and regular microsurface pattern. GA-FGs are covered with normal foveolar epithelium, forming a so-called endless glands pattern in the deeper region, which are mainly composed of chief cells or parietal cells. Most tumors exhibit submucosal invasion, but lymphovascular invasion and nodal metastasis are rare. Regarding the treatment of GA-FG, endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR) are effective treatment methods.

Conclusions

GA-FG is a rare tumor that typically follows a benign course. This neoplasm has distinct endoscopic and pathological features and could be treated by ESD or EMR.

Genetic analysis of fundic gland‑type gastric adenocarcinoma

This study aimed to analyze the molecular characteristics of gastric adenocarcinoma of the fundic-gland type (GAFG) and explore the possible mechanism of tumor development. Samples from 10 Chinese patients with GAFG were collected at the Peking University International Hospital and Liaocheng People's Hospital between January 2015 and March 2022. The nucleic acid sequence of Epstein Barr virus-encoded RNA (EBV-EBER) was detected by in situ hybridization. Genetic mutation information for GNAS, KRAS, NRAS, BRAF, PIK3CA, TP53, APC, CTNNB1, HER2, MLH1, MSH2, MSH6, and PMS2 was obtained by Next-Generation Sequencing, and the relevant literature was reviewed. A total of eight instances of missense mutations were detected, consisting of seven cases with GNAS mutations, two cases with KRAS mutations, and one case with a TP53 mutation. Additionally, two patients had simultaneous missense mutations in GNAS and KRAS. Nonsynonymous mutations in APC, CTNNB1, NRAS, BRAF, PIK3CA, HER2, MLH1, MSH2, MSH6, or PMS2 were not observed in any cases. In addition, all tumors were EBER-negative. GAFG exhibits diversity at the molecular level, and GNAS mutations are more common than KRAS mutations, TP53 mutations, and microsatellite instability. To date, no association between EBV/HER2 and GAFG has been found.

Clinicopathological Features and the Prevalence of Oxyntic Gland Neoplasm: A Single-center Retrospective Study

Objective We explored the clinicopathological characteristics and disease frequency of oxyntic gland neoplasms (OGNs). Methods We retrospectively evaluated the data of patients pathologically diagnosed with OGN at an internal medicine clinic. Patients A total of 13,240 upper gastrointestinal endoscopies were performed on 7,488 patients between December 1, 2017, and March 31, 2021. Results We identified 27 patients with 30 histopathologically confirmed OGNs, yielding a disease frequency of 0.36% (27/7,488). Furthermore, multiple simultaneous lesions were found in 3 of 27 patients (11%). One (3.3%) of the 30 lesions was present in the antrum, whereas the remaining lesions occurred in the body of the stomach. Nine (33%) of the 27 patients had no history of Helicobacter pylori infection, whereas the remaining 18 (67%) were either currently or had been previously infected. Nevertheless, 27/30 lesions (90%) still occurred in non-atrophied regions. After endoscopic treatment, a histopathological examination of the resected specimens revealed submucosal infiltration in 8 (44%) of the 18 lesions; however, none of the lesions showed submucosal desmoplasia. For all patients with submucosal involvement, only observation was performed. There were no recurrent lesions found on follow-up. Conclusion The period prevalence of OGN was 0.36%, which is much higher than previously reported. The discovery of a small submucosal appearing lesion with a faded yellow or white color and dilated microvasculature, especially in a non-atrophic area of the stomach, should raise suspicion for an OGN, which can be endoscopically managed.

Oxyntic Gland Adenoma in a Patient With Refractory Reflux

A 58-year-old African American male was referred for endoscopic evaluation due to a persistent nine-year history of reflux. Previous endoscopy nine years ago revealed a small hiatal hernia and chronic gastritis caused by Helicobacter pylori (H. pylori), which was treated with triple therapy. During the current endoscopic evaluation, findings consistent with reflux esophagitis were identified, along with the discovery of an incidental 6 mm sessile polyp in the gastric fundus. Pathological examination revealed the presence of an oxyntic gland adenoma (OGA). Otherwise, the stomach was found to be unremarkable endoscopically and histologically. OGA is a rare gastric neoplasm that is primarily observed in Japan, with very few reported cases in North America. Studies have suggested a potential association with antacids, while the role of H. pylori in the development of OGA remains controversial. Our patient's OGA was completely resected during the endoscopy, with no recurrence noted on the three-month follow-up.

[Clinicopathological features of Helicobacter pylori-negative early gastric cancer]

OBJECTIVE

To investigate the clinicopathological features of Helicobacter pylori (Hp)-negative early gastric cancer.

METHODS

The clinicopathological data of 30 cases of Hp-negative early gastric cancer were collected retrospectively at Pingdingshan Medical District, 989 Hospital of PLA Joint Logistics Support Force, and Beijing Chaoyang Hospital, Capital Medical University, from 2009 to 2021, and the histomorphological characteristics and immunophenotype were observed, and combined with the literature to explore.

RESULTS

The median age of 30 patients was 58.5 years (range: 21-80 years), including 13 males and 17 females. The upper part of the stomach was 13 cases, the middle part of the sto-mach was 9 cases, and the lower part of the stomach was 8 cases. The median diameter of the tumor was 11 mm (range: 1-30 mm). According to the Paris classification, 9 cases were 0-Ⅱa, 7 cases were 0-Ⅱb, and 14 cases were 0-Ⅱc. Endoscopic examination showed that 18 cases of lesions were red, 12 cases of lesions were faded or white, and microvascular structures and microsurface structures were abnormal. In all the cases, collecting venules were regularly arranged in the gastric body and corner mucosa. There were 18 cases of well differentiated adenocarcinoma in the mucosa. The tumor presented glandular tubular-like and papillary structure, with dense glands and disordered arrangement; the cells were cuboidal or columnar, with increased nuclear chromatin and loss of nuclear polarity, and most of them expressed gastric mucin. Signet-ring cell carcinoma was found in 7 cases, all the cancer tissues were composed of signet-ring cells, and the cancer cells were mainly distributed in the middle layer to the surface layer of mucosa. Gastric oxyntic gland adenoma (gastric adenocarcinoma of the fundic gland type confined to mucosa) in 2 cases, gastric adenocarcinoma of the fundic gland type in 2 cases, and gastric adenocarcinoma of fundic gland mucosa type in 1 case. The tumor tissue was composed of branching tubular glands, except 1 case of mucosal surface epithelium was partially neoplastic, the other 4 cases of mucosal surface epi-thelium were all non-neoplastic; the cells were arranged in a single layer, and the nucleus was close to the basal side, and the nucleus was only slightly atypical. Pepsinogen I and H+/K+ ATPase were positive in 5 cases of gastric fundus gland type tumors, and 1 case of foveolar-type tumor cells at the surface and depth of mucosa showed MUC5AC positive. The gastric mucosa adjacent to cancer was generally normal in all cases, without atrophy, intestinal metaplasia and Hp.

CONCLUSION

Hp-negative early gastric cancer is a heterogeneous disease group with various histological types, and tubular adenocarcinoma and signet-ring cell carcinoma are common. Tubular adenocarcinoma mostly occurs in the elderly and the upper to middle part of the stomach, while signet-ring cell carcinoma mostly occurs in young and middle-aged people and the lower part of the stomach. Gastric neoplasm of the fundic gland type is relatively rare.

Preoperative endoscopy and pathology report of the specimen to be recommended in sleeve gastrectomy?

Objective

Preoperative upper gastrointestinal endoscopy (UGIE) and postoperative histopathological examination (HPE) of resected specimens are still controversial issues in bariatric surgery.

Methods

A retrospective review of prospectively collected laparoscopic sleeve gastrectomies (SG) performed at our institution for morbid obesity was carried out. All patients underwent pre-operative UGIE with biopsy, post-operative HPE and conventional post-operative follow-up.

Results

From January 2019 through January 2021 we performed a total of 501 laparoscopic SG. A total of 12 (2.4%) neoplasms were found, 2 evident at preoperative UGIE, 4 detected during operation, and 6 at HPE. Eight of these 12 cases had some malignant potential and 5 would not have been detected without HPE of the specimen. The most significant unexpected case was a fundic gland type adenocarcinoma in a 64-year-old female with severe obesity.

Conclusion

On the basis of our clinical experience, we recommend both preoperative endoscopic assessment and postoperative HPE of the specimen to provide the best available treatment to these patients.

A Standardized Pathology Report for Gastric Cancer: 2nd Edition

The first edition of 'A Standardized Pathology Report for Gastric Cancer' was initiated by the Gastrointestinal Pathology Study Group of the Korean Society of Pathologists and published 17 years ago. Since then, significant advances have been made in the pathologic diagnosis, molecular genetics, and management of gastric cancer (GC). To reflect those changes, a committee for publishing a second edition of the report was formed within the Gastrointestinal Pathology Study Group of the Korean Society of Pathologists. This second edition consists of two parts: standard data elements and conditional data elements. The standard data elements contain the basic pathologic findings and items necessary to predict the prognosis of GC patients, and they are adequate for routine surgical pathology service. Other diagnostic and prognostic factors relevant to adjuvant therapy, including molecular biomarkers, are classified as conditional data elements to allow each pathologist to selectively choose items appropriate to the environment in their institution. We trust that the standardized pathology report will be helpful for GC diagnosis and facilitate large-scale multidisciplinary collaborative studies.

Transcriptome analysis reveals the essential role of NK2 homeobox 1/thyroid transcription factor 1 (NKX2-1/TTF-1) in gastric adenocarcinoma of fundic-gland type

BACKGROUND

Gastric adenocarcinoma of fundic-gland type (GA-FG) is a gastric malignancy with little relation to Helicobacter pylori. Clinical characteristics of GA-FG have been established, but molecular mechanisms leading to tumorigenesis have not yet been elucidated.

METHODS

We subjected three GA-FG tumors-normal mucosa pairs to microarray analysis. Network analysis was performed for the top 30 up-regulated gene transcripts, followed by immunohistochemical staining to confirm the gene expression analysis results. AGS and NUGC4 cells were transfected with the gene-encoding NK2 homeobox 1/thyroid transcription factor 1 (NKX2-1/TTF-1) to evaluate transcriptional changes in its target genes.

RESULTS

Comprehensive gene expression analysis identified 1410 up-regulated and 1395 down-regulated gene probes with ≥ two-fold difference in expression. Among the top 30 up-regulated genes in GA-FG, we identified transcription factor NKX2-1/TTF-1, a master regulator of lung/thyroid differentiation, together with surfactant protein B (SFTPB), SFTPC, and secretoglobin family 3A member 2(SCGB3A2), which are regulated by NKX2-1/TTF-1. Immunohistochemical analysis of 16 GA-FG specimens demonstrated significantly higher NKX2-1/TTF-1 and SFTPB levels, as compared to that in adjacent normal mucosa (P < 0.05), while SCGB3A2 levels did not differ (P = 0.341). Transduction of NKX2-1/TTF-1 into AGS and NUGC4 cells induced transactivation of SFTPB and SFTPC, indicating that NKX2-1/TTF-1 can function as normally in gastric cells as it can in the lung cells.

CONCLUSIONS

Our first transcriptome analysis of GA-FG indicates significant expression of NKX2-1/TTF1 in GA-FG. Immunohistochemistry and cell biology show ectopic expression and normal transactivation ability of NKX2-1/TTF-1, suggesting that it plays an essential role in GA-FG development.

A standardized pathology report for gastric cancer: 2nd edition

The first edition of 'A Standardized Pathology Report for Gastric Cancer' was initiated by the Gastrointestinal Pathology Study Group of the Korean Society of Pathologists and published 17 years ago. Since then, significant advances have been made in the pathologic diagnosis, molecular genetics, and management of gastric cancer (GC). To reflect those changes, a committee for publishing a second edition of the report was formed within the Gastrointestinal Pathology Study Group of the Korean Society of Pathologists. This second edition consists of two parts: standard data elements and conditional data elements. The standard data elements contain the basic pathologic findings and items necessary to predict the prognosis of GC patients, and they are adequate for routine surgical pathology service. Other diagnostic and prognostic factors relevant to adjuvant therapy, including molecular biomarkers, are classified as conditional data elements to allow each pathologist to selectively choose items appropriate to the environment in their institution. We trust that the standardized pathology report will be helpful for GC diagnosis and facilitate large-scale multidisciplinary collaborative studies.

KRAS mutation in intrahepatic cholangiocarcinoma: Linkage with metastasis-free survival and reduced E-cadherin expression

BACKGROUND AND AIMS

Although KRAS mutations are the major driver of intrahepatic cholangiocarcinoma (ICC), their role remains unexplored. This study aimed to elucidate the prognostic effects, association with clinicopathologic characteristics and potent functions of KRAS mutations in ICC.

METHODS

A hundred and seven resected stage I-III ICCs were analysed for KRAS mutation status and its link with clinicopathological features. An independent validation cohort (n = 138) was included. In vitro analyses using KRAS-mutant ICC cell lines were performed.

RESULTS

KRAS mutation was significantly associated with worse overall survival in stage I-III ICCs, which was validated in an independent cohort. Recurrence-free survival did not significantly differ between cases with and without KRAS mutations, but if limited to recurrence with extrahepatic metastasis, KRAS-mutant cases showed significantly worse distant metastasis-free survival than KRAS-wild cases showed. KRAS mutations were associated with frequent tumour budding with reduced E-cadherin expression. In vitro, KRAS depletion caused marked inhibition of cell growth and migration together with E-cadherin upregulation in KRAS-mutant ICC cells. The RNA-sequencing assay revealed that KRAS depletion caused MYC pathway downregulation and interferon pathway upregulation.

CONCLUSIONS

Our observations suggest that KRAS mutations are associated with aggressive behaviour of ICC, especially the development of extrahepatic metastasis. Mutant KRAS is likely to change the adhesive status of ICC cells, affect the responsiveness of tumour cells to interferon immune signals, and consequently promote extrahepatic metastasis. KRAS mutation status, which predicts the prognoses of patients with ICC after surgical resection, is expected to help stratify patients better for individual postoperative treatment strategies.

Endoscopic features of oxyntic gland adenoma and gastric adenocarcinoma of the fundic gland type differ between patients with and without Helicobacter pylori infection: a retrospective observational study

BACKGROUND

The endoscopic features of oxyntic gland adenoma and gastric adenocarcinoma of the fundic gland type have not been fully investigated in relation to Helicobacter pylori infection status. We compared the morphology, color, and location of these lesions between patients with and without H. pylori infection.

METHODS

We retrospectively enrolled 165 patients (180 lesions) from 10 institutions. We divided the patients into the (i) Hp group (patients with current H. pylori infection [active gastritis, n = 13] and those with past infection [inactive gastritis, n = 76]) and (ii) uninfected group (H. pylori-uninfected patients, n = 52). We compared the clinical and endoscopic features of the two groups. We also performed an analysis between (i) lesions with atrophy of the surrounding gastric mucosa (atrophy group) and (ii) lesions without atrophy of the surrounding gastric mucosa (non-atrophy group).

RESULTS

The average age was older in the Hp group than in the uninfected group (68.1 ± 8.1 vs. 63.4 ± 8.7 years, p < 0.01). Although the difference was not statistically significant (p = 0.09), multiple lesions were observed in 9 of 89 patients (10.1%) in the Hp group and in only 1 of 52 patients (1.9%) in the uninfected group. Meanwhile, significant differences were observed in the prevalence of lesions located in the gastric fornix or cardia (uninfected group: 67.3% vs. Hp group: 38.0%, p < 0.01), with an elevated morphology (80.0% vs. 56.0%, p < 0.01), with a subepithelial-like appearance (78.2% vs. 42.0%, p < 0.01), and with a color similar to that of the peripheral mucosa (43.6% vs. 25.0%, p = 0.02). The male-to-female ratio, lesion size, and presence or absence of vascular dilatation or black pigmentation on the surface were not different between the two groups. In the analysis comparing lesions with and without mucosal atrophy, the prevalence of multiple lesions was significantly higher (p = 0.02) in the atrophy group (5/25 patients, 20.0%) than in the non-atrophy group (7/141 patients, 5.0%).

CONCLUSIONS

The endoscopic features of oxyntic gland adenoma and gastric adenocarcinoma of the fundic gland type differ between patients with and without H. pylori infection.

SP70 is a potential biomarker to identify gastric fundic gland neoplasms

Background

Gastric neoplasms with fundic gland differentiation include oxyntic gland adenomas (OGAs) and gastric adenocarcinomas of fundic gland type (GA-FGs). Due to their well-differentiated and similar morphology with normal fundic glands, it is usually challenging to identify these lesions in pathological diagnosis, especially in biopsy specimens. This study aims to explore and verify the potential role of a newly developed monoclonal antibody (McAb) NJ001 (SP70) in differentiating fundic neoplasms from non-neoplastic fundic gland lesions.

Methods

Twenty-three cases of histological confirmed gastric fundic gland neoplasms were obtained, including 12 cases of OGAs and 11 of GA-FGs. Fifty cases of fundic gland polyps (FGPs) were taken as the control group. Six cases of well-differentiated gastric neuroendocrine tumors (NETs) (easily misdiagnosed) were also obtained. Key clinicopathological information was collected. SP70 immunostaining was performed (with para-tumor normal fundic glands as internal control). The positive intensity and staining pattern of SP70 were analyzed and compared.

Results

In normal gastric mucosa, SP70 was strongly and diffusely stained on the cytoplasm in fundic glands, but not in the foveolar epithelium. Therefore, a zonal distribution of SP70 was observed in normal mucosa. FGPs (50/50, 100%) shared a similar expression pattern with normal fundic glands. In fundic gland neoplasms, a significant down-expression of SP70 was observed in both OGAs and GA-FGs. The positive rate of SP70 in fundic gland neoplasms (6/23, 26.1%) was significantly lower than that in FGPs (100%) (P<0.0001). There was no difference in SP70 expression between OGAs (3/12, 25.0%) and GA-FGs (3/11, 27.2%) group (P>0.05). In these 6 NET cases, SP70 was weak to moderate intensity in the majority of tumor cells (with a different expression pattern).

Conclusion

Down-expression of SP70 is a specific feature to fundic gland neoplasms including OGAs and GA-FGs. Therefore, SP70 can serve as a potential biomarker in the identification and differential diagnosis of fundic gland neoplasms.

Pepsinogen I- and H+/K+-ATPase-immunohistochemical Positivity in Endoscopically Resected Early Gastric Neoplasia

Gastric adenocarcinoma of the fundic gland type (GAFG) has been recently classified by the World Health Organization (WHO), however, clinicopathologic features of pepsinogen I- or H+/K+-ATPase-positive gastric tumors remain unclear. Therefore, this study evaluates the frequency and clinicopathologic features of those tumors, using a tissue microarray block to identify pepsinogen I- or H+/K+-ATPase-positive tumors from 810 endoscopically resected, early gastric epithelial tumors. The frequency of pepsinogen I-positive lesions was 2.1%, and that of H+/K+-ATPase-positive lesions was 2.0%. Pepsinogen I- or H+/K+-ATPase positivity was not observed in undifferentiated-type tumors, while gastric tumors with morphologic similarity to fundic glands were positive for pepsinogen I- or H+/K+-ATPase. We divided pepsinogen I- or H+/K+-ATPase-positive gastric tumors into group A, with fundic gland-like structure, or group B, without fundic gland-like structure. The frequency of group A was 1.6%: 46.2% were positive only for pepsinogen I and 53.8% for H+/K+-ATPase and pepsinogen I. The frequency of group B was 1.5%: 25% were positive only for pepsinogen I, 8.3% for H+/K+-ATPase and pepsinogen I, and 66.7% only for H+/K+-ATPase. The 2 tumor groups differed in location and endoscopic features. Hematoxylin and eosin staining showed that group B had more exposed tumors to the surface, larger nuclei, and more background atrophy than group A. Immunostaining showed significantly higher positivity rates for MUC5AC, CD10, CDX2, and p53 expression, and a higher Ki-67 labeling score. Our results provide novel insights into the pathology of early gastric tumors with histologic or immunohistochemical evidence of fundic gland differentiation.

Pathological Diversity of Gastric Cancer from the Viewpoint of Background Condition

BACKGROUND

The prevalence of Helicobacter pylori infection and chronic atrophic gastritis is decreasing in Japan, which has led to a decline in the incidence of gastric cancer. However, there are various subtypes of gastric cancer that arise from the background mucosa without H. pylori infection, and their histological characteristics are distinct from those of gastric cancer with chronic atrophic gastritis.

SUMMARY

In this review, after a brief overview of conventional gastric carcinoma with H. pylori infection, including its molecular classification, histological characteristics of gastric cancer after eradicating H. pylori are described. The clinicopathological characteristics of gastric cancer independent of H. pylori infection are then explained. Autoimmune gastritis (type A gastritis) increases the risk of gastric adenocarcinoma and neuroendocrine tumors. Gastric carcinoma without H. pylori infection has various histological subtypes, including fundic gland-type adenocarcinoma (oxyntic gland adenoma), foveolar-type adenocarcinoma/adenoma, signet ring cell carcinoma, and adenocarcinoma of the esophagogastric junction. In addition, some familial gastric cancer syndromes, including hereditary diffuse gastric cancer, familial adenomatous polyposis, and gastric adenocarcinoma and proximal polyposis of the stomach, are also discussed. Key Messages: Although the incidence of gastric cancer will decrease in the near future, the diversity of gastric cancer pathology will be enhanced because H. pylori-negative gastric cancer will have a significant impact on the clinical practice guidelines for gastric cancer. Gastroenterologists and pathologists should be aware of the morphological diversity of H. pylori-negative gastric cancer, and attention should be paid to the status of the background gastric mucosa while examining gastric cancer.

Some Morphology Frontiers of Dysplasia in the Tubular Gastrointestinal Tract: The Rodger C. Haggitt Memorial Lecture

This review, based on the content of the 2020 US Gastrointestinal Pathology Society's Rodger Haggitt Lecture, concerns an array of tubular gastrointestinal tract dysplastic or possible "predysplastic lesions" with an almost purely morphologic focus based on our collaborative efforts over the past few years. These processes include esophageal epidermoid metaplasia, Barrett esophagus-associated dysplasia, polypoid gastric dysplastic lesions, small intestinal dysplasia, and the ability of metastases to mimic it, the controversial "serrated epithelial change" encountered in the setting of long-standing ulcerative and Crohn colitis, and recently described anal columnar human papilloma virus-associated neoplasms.

The updated WHO classification of digestive system tumours-gastric adenocarcinoma and dysplasia

The fifth edition of the World Health Organization (WHO) classification of digestive system tumours was published in 2019. The classification of invasive carcinoma is basically the same as in the fourth edition, but the description of each histological type has been updated, and some rare subtypes such as micropapillary carcinoma, gastric adenocarcinoma of the fundic gland type and undifferentiated carcinoma have been added and explained. Although this classification did not provide specific numerical criteria for the diagnosis of signet-ring cell carcinoma in poorly cohesive carcinoma, an additional study defined signet-ring cell carcinoma as having more than 90% signet-ring cells. The molecular classification of gastric cancer (Epstein-Barr virus-positive type, microsatellite instability type, genomically stable type, chromosomally unstable type) was additionally introduced. Many pages in the present classification have been devoted to precancerous lesions, and this article focuses on foveolar-type adenoma/dysplasia.

Characteristic endoscopic findings of gastric adenocarcinoma of fundic-gland mucosa type

BACKGROUND AND STUDY AIMS

Gastric adenocarcinoma of fundic-gland type (GA-FG) was first proposed as a new entity of gastric adenocarcinoma in 2010. Subsequently, gastric adenocarcinoma of fundic-gland mucosa type (GA-FGM) was reported as a subtype of gastric adenocarcinoma. This study aimed to investigate the endoscopic findings of GA-FGM and to evaluate the differences between GA-FGM and GA-FG.

PATIENTS AND METHODS

This was a single-center retrospective study. Participants were selected from patients with gastric cancer treated at Fukuoka University Chikushi Hospital, between September 2007 and May 2020. Patients histologically diagnosed with GA-FGM or GA-FG were enrolled, and endoscopic findings were analyzed in detail.

RESULTS

A total of 12 GA-FGM lesions (12 patients) and 14 GA-FG lesions (13 patients) were analyzed. The two lesion types showed similar features: most lesions were of elevated type, located in the upper stomach, and developed in the stomach without Helicobacter pylori infection. On conventional endoscopy using the dye-spraying method, well-demarcated fine granular areas were observed in 7 GA-FGM lesions (58%) but not in any GA-FG lesions, with a significant difference between the two groups (P = 0.001). Magnifying endoscopy with narrow-band imaging (NBI) showed that 11 GA-FGM lesions (92%) met the diagnostic criteria for cancer according to the vessel plus surface classification system, whereas none of the GA-FG lesions met the same criteria (0%, 0/14) (P = 0.001).

CONCLUSION

Our results suggest that magnifying endoscopy with NBI is a potentially useful method for the diagnosis of GA-FGM.

Gastric epithelial neoplasm of fundic-gland mucosa lineage: proposal for a new classification in association with gastric adenocarcinoma of fundic-gland type

BACKGROUND

Gastric adenocarcinoma of fundic-gland type (GA-FG) is a rare variant of gastric neoplasia. However, the etiology, classification, and clinicopathological features of gastric epithelial neoplasm of fundic-gland mucosa lineage (GEN-FGML; generic term of GA-FG related neoplasm) are not fully elucidated. We performed a large, multicenter, retrospective study to establish a new classification and clarify the clinicopathological features of GEN-FGML.

METHODS

One hundred GEN-FGML lesions in 94 patients were collected from 35 institutions between 2008 and 2019. We designed a new histopathological classification of GEN-FGML using immunohistochemical analysis and analyzed via clinicopathological, immunohistochemical, and genetic evaluation.

RESULTS

GEN-FGML was classified into 3 major types; oxyntic gland adenoma (OGA), GA-FG, and gastric adenocarcinoma of fundic-gland mucosa type (GA-FGM). In addition, GA-FGM was classified into 3 subtypes; Type 1 (organized with exposure type), Type 2 (disorganized with exposure type), and Type 3 (disorganized with non-exposure type). OGA and GA-FG demonstrated low-grade epithelial neoplasm, and GA-FGM should be categorized as an aggressive variant of GEN-FGML that demonstrated high-grade epithelial neoplasm (Type 2 > 1, 3). The frequent presence of GNAS mutation was a characteristic genetic feature of GEN-FGML (7/34, 20.6%; OGA 1/3, 33.3%; GA-FG 3/24, 12.5%; GA-FGM 3/7, 42.9%) in mutation analysis using next-generation sequencing.

CONCLUSIONS

We have established a new histopathological classification of GEN-FGML and propose a new lineage of gastric epithelial neoplasm that harbors recurrent GNAS mutation. This classification will be useful to estimate the malignant potential of GEN-FGML and establish an appropriate standard therapeutic approach.

Endoscopic resection is a suitable initial treatment strategy for oxyntic gland adenoma or gastric adenocarcinoma of the fundic gland type

The aim of this study was to reveal the histological features of oxyntic gland adenomas and gastric adenocarcinoma of the fundic-gland type (GA-FG). We retrospectively examined the histological features of 126 lesions of oxyntic gland adenoma and/or GA-FG in 116 patients. The prevalence of oxyntic gland adenomas and GA-FG was approximately equal. The majority of the lesions were resected by endoscopic mucosal resection using a diathermic snare (EMR, n = 42) or endoscopic submucosal dissection (ESD, n = 72). Histologically, there were no lesions with invasion at the level of the muscularis propria or deeper, and lymphovascular invasion was present in 1.6%. Of the ESD and EMR specimens, there were no lesions that were positive for vertical margins. Among the eight GA-FG patients with deep (≥ 500 μm) submucosal invasion, six were treated with endoscopic resection alone, and no recurrence was documented. No patients died of the disease during the median follow-up period of 14.5 months. In conclusion, all lesions were confined to the mucosa or submucosa and were negative for vertical margins. Lymphovascular invasion was present in only 1.6% of the patients. Thus, we believe that endoscopic resection is a suitable initial treatment method for oxyntic gland adenoma and GA-FG.

Helicobacter pylori-negative Gastric Cancer

<i>Helicobacter pylori (H. pylori)</i>-negative gastric cancer is diagnosed when gastric malignancies are found in patients in <i>H. pylori</i>-naïve stomachs. There are four types of noncardiac <i>H. pylori</i>-negative gastric cancers. The signet ring cell-type poorly cohesive carcinoma is most common, followed by the chief cell-predominant type gastric adenocarcinoma of the fundic gland. Extremely well-differentiated adenocarcinoma of the corpus and well-differentiated pyloric gland cancers are rare outside Japan because of country-specific differences in diagnostic criteria. In endemic areas of <i>H. pylori</i> infection, strict criteria are required for diagnosing an <i>H. pylori</i>-naïve stomach. Both invasive and noninvasive <i>H. pylori</i> tests should show negative results in a subject without a history of <i>H. pylori</i> infection. Furthermore, the serum pepsinogen (PG) assay and endoscopic findings of the background gastric mucosa are required to discriminate subjects with past infections owing to spontaneous regression or unintended eradication of <i>H. pylori</i>. There should be no gastric corpus atrophy (PG I ≤70 ng/mL and PG I/II ≤3.0). Gastroscopy should reveal a regular arrangement of collecting venules without gastric xanthoma, metaplastic gastritis, or advanced atrophy over the angle. On biopsy, there should be no gastric atrophy, intestinal metaplasia, neutrophils, or <i>H. pylori</i> infiltration, and only a mild degree of mononuclear cell infiltration is permitted. The types and characteristics of noncardiac <i>H. pylori</i>-negative gastric cancers are summarized in this review, along with current diagnostic challenges found in Korea.

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.

Helicobacter Infection and Gastric Adenoma

Background: We aimed to provide insight into the actual frequencies of gastric adenoma types and their association with gastritis status and associated mucosal changes with a focus on Helicobacter infection and the operative link on gastritis assessment (OLGA)/operative link on gastric intestinal metaplasia assessment (OLGIM) staging. Methods: From the archive of the Institute of Pathology in Bayreuth, we collected a consecutive series of 1058 gastric adenomas diagnosed between 1987 and 2017. Clinicopathological parameters retrieved from diagnostic reports included adenoma type and localization, associated mucosal changes in antrum and corpus (i.e., type of gastritis, the extent of intestinal metaplasia and atrophy), gender, date of birth, and date of diagnosis. Results: Intestinal-type adenoma was the most frequent adenoma (89.1%), followed by foveolar-type adenoma (4.3%), pyloric gland adenoma (3.4%), adenomas associated with hereditary tumor syndromes (2.8%), and oxyntic gland adenoma (0.4%). Adenomas were found in the background of Helicobacter pylori (H. pylori) gastritis in 23.9%, Ex-H. pylori gastritis in 36.0%, autoimmune gastritis in 24.8%, chemical reactive gastritis in 7.4%, and others in 0.1%. More than 70% of patients with gastric adenomas had low-risk stages in OLGA and OLGIM. Conclusions: We found a higher frequency of foveolar-type adenoma than anticipated from the literature. It needs to be questioned whether OLGA/OLGIM staging can be applied to all patients.

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.

Histopathologic Change of a Case of Gastric Oxyntic Neoplasm (Gastric Adenocarcinoma of Fundic Gland Mucosa Type) Through 5 Years With Concurrent Other Oxyntic Gland Lesions

Some gastric epithelial neoplasms show predominant chief cell differentiation (oxyntic gland neoplasms), in which the entity of "gastric adenocarcinoma of fundic gland type" was firstly designated, whereas a possible more aggressive subgroup "gastric adenocarcinoma of fundic gland mucosa type" (GA-FGM) was subsequently proposed. However, the histopathologic progression mode of these neoplasms has not been sufficiently reported. In this article, we describe a case of GA-FGM in which we could observe its progression during 5 years. The tumor was removed by endoscopic submucosal dissection 5 years after the first biopsy, which had already shown a feature of oxyntic gland neoplasm. During the follow-up period, the endoscopy revealed little change in the tumor appearance. However, the histology of endoscopic submucosal dissection showed submucosal extension with its histological progression. Besides, other oxyntic gland neoplasms of the stomach were observed metachronously or synchronously, giving an implication about a common pathogenetic basis of these lesions.

Diffuse MIST1 expression and decreased α1,4-linked N-acetylglucosamine (αGlcNAc) glycosylation on MUC6 are distinct hallmarks for gastric neoplasms showing oxyntic gland differentiation

AIMS

Gastric neoplasms showing oxyntic gland differentiation (GAOGs) constitute a gastric neoplasm subtype that shows low atypia, thus similar to non-neoplastic gastric oxyntic glands. Therefore, their diagnosis in biopsy specimens is difficult. GAOGs were first described in 2007, and introduced in the latest World Health Organization classification book as gastric adenocarcinoma of the fundic gland type (GA-FG) and oxyntic gland adenoma. Previously, we assessed α1,4-linked N-acetylglucosamine (αGlcNAc) residues attached to the MUC6 scaffold in gastric neoplasms, and observed decreased αGlcNAc glycosylation in both differentiated-type gastric cancer and high-grade pyloric gland adenoma (PGA), a gastric cancer precursor. GA-FG and PGA often harbour the same mutations. However, the αGlcNAc status in GAOGs remained unknown. To elucidate αGlcNAc expression in GAOGs, we performed the study.

METHODS AND RESULTS

We assessed the expression of αGlcNAc; the mucin markers MUC6, MUC5AC, and MUC2; the gastric gland cell markers MIST1, pepsinogen 1 (PG1), H/K-ATPase and chromogranin-A (CGA); and the proliferation marker Ki67 in 13 GAOG lesions. All 13 (100%) were MUC6-positive, whereas 10 (76.2%) were αGlcNAc-negative. Moreover, all 13 (100%) were MIST1- and PG1-positive, three (23.1%) were MUC5AC-positive, four (30.8%) were H/K-ATPase-positive, and one (7.7%) was CGA-positive.

CONCLUSIONS

GAOGs frequently lost αGlcNAc residues on MUC6, but expressed the gastric gland progenitor marker MIST1 and aberrantly expressed various types of gastric gland cell lineage marker, suggestive of immature differentiation to gastric gland cells. Thus, diffuse MIST1 positivity and decreased αGlcNAc glycosylation on MUC6-positive cells could serve as important biomarkers for the histopathological diagnosis of GAOG.