Intestinal-type gastric dysplasia in Helicobacter pylori-naïve patients

Multiple metachronous foveolar-type gastric adenomas in a Helicobacter pylori-naïve patient with long-term use of a proton pump inhibitor: a case report

A 69-year-old man undergoing long-term administration of a proton-pump inhibitor (PPI) underwent upper endoscopy, which found a small, whitish, flat lesion in the fundic gland (oxyntic) mucosa. The patient had never received treatment for Helicobacter pylori (Hp) infection, and diagnostic testing for Hp was negative, suggesting an Hp-naïve status. Two years later, the lesion appeared markedly enlarged and was endoscopically resected. Histological examination revealed a low-grade foveolar-type gastric adenoma (FGA), predominantly expressing MUC5AC by immunohistochemistry. Two years later, while PPI therapy was continued, three new flat lesions were found. These were endoscopically resected and histologically diagnosed as low-grade FGAs as before, suggesting that multiple metachronous tumors had developed in a short period of time during long-term PPI administration. A KRAS mutation and a CTNNB1 mutation were identified in the tumor. To our best knowledge, this is the first report of potentially PPI-associated multiple metachronous FGAs in an Hp-naïve patient. Here we report a case of multiple foveolar-type gastric adenomas with rapid metachronous recurrences during long-term use of a proton pump inhibitor in Helicobacter pylori-naïve patient.

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.

Gastric Adenocarcinomas with CDX2 Induction Show Higher Frequency of TP53 and KMT2B Mutations and MYC Amplifications but Similar Survival Compared with Cancers with No CDX2 Induction

Background: Gastric cancer is one of the most prevalent gastrointestinal cancers. Mortality is high, and improved treatments are needed. A better understanding of the pathophysiology of the disease and discovery of biomarkers for targeted therapies are paramount for therapeutic progress. CDX2, a transcription factor of hindgut specification, is induced in several gastric cancers, especially with intestinal differentiation, and could be helpful for defining sub-types with particular characteristics. Methods: Gastric cancers with induced CDX2 mRNA expression were identified from the gastric cohort of The Cancer Genome Atlas (TCGA) and were compared with cancers that had no CDX2 mRNA induction. Induced CDX2 mRNA expression was defined as mRNA expression z-score relative to all samples above 0, and non-induced CDX2 mRNA expression was defined as mRNA expression z-score relative to all samples below -1. Results: Patients with gastric cancers with CDX2 mRNA induction were older, had less frequently diffuse histology, and more often had mutations in TP53 and KMT2B and amplifications in MYC. CDX2 induction was correlated with HNF4α induction and was reversely correlated with SOX2. Gastric cancers with CDX2 mRNA induction showed lower PD-L1 expression than cancers with lower CDX2 expression but did not differ in CLDN18 mRNA expression. Progression-free and overall survival of the two groups was also not significantly different. Conclusion: Gastric cancers with CDX2 mRNA induction displayed specific characteristics that differentiate them from cancers with no CDX2 induction and could be of interest for optimizing current and future therapies.

Prevalence of Gastric Epithelial Tumors in Helicobacter pylori-uninfected Individuals Undergoing a Medical Checkup

Objective This study investigated the prevalence of gastric epithelial tumor in Helicobacter pylori-uninfected subjects who underwent esophagogastroduodenoscopy (EGD) as part of an annual checkup. Methods A total of 20,540 EGD examinations of H. pylori-uninfected individuals (12,917 men, 7,623 women; mean age 51.5±9.2 years old) were performed between April 2016 and March 2023. The prevalence of gastric epithelial tumor discovery and the size and location of each lesion type were analyzed. Results According to 20,540 examinations, 61 gastric epithelial tumors were endoscopically and histologically diagnosed in 58 of the subjects, with a prevalence rate of 0.28%. These tumors included signet-ring carcinoma (n=10, 0.05%), gastric adenocarcinoma of fundic-gland type (n=10, 0.05%), intestinal-type well-differentiated adenocarcinoma (n=2, 0.01%), and raspberry-type gastric foveolar tumors (n=36, 0.18%). One subject had two intestinal-type well-differentiated adenocarcinomas, and two each had two raspberry-type gastric foveolar tumors. The mean sizes of the signet-ring carcinomas, gastric adenocarcinoma of fundic-gland type, intestinal-type well-differentiated adenocarcinomas, and raspberry-type gastric foveolar tumors were 6.4, 4.7, 5.0, and 3.4 mm, respectively. Each lesion was located at a specific site in the stomach characteristic of its type. Conclusion In the present H. pylori-uninfected subjects, the prevalence of gastric epithelial tumors found on an EGD examination was 0.28%. Endoscopic examination should be performed in H. pylori-uninfected individuals to detect such tumors in characteristic locations.

Gastric dysplastic lesions in Helicobacter pylori-naïve stomach: Foveolar-type adenoma and intestinal-type dysplasia

Reports of Helicobacter pylori (Hp)-naïve gastric neoplasm (HpNGN) cases have been rapidly increasing due to the recent increase in the Hp-naïve population in Japan. Most HpNGNs exhibit the gastric immunophenotype and a low malignant potential regardless of histological type. Especially, foveolar-type gastric adenoma (FGA) and intestinal-type gastric dysplasia (IGD) rarely progress to invasive carcinoma. FGA is a foveolar epithelial neoplasm that occurs in the fundic gland (oxyntic gland) mucosa and is classified as the flat type or raspberry type (FGA-RA). The flat type is a large, whitish flatly elevated lesion while FGA-RA is a small reddish polyp. Genomically, the flat type is characterized by APC and KRAS gene mutations and FGA-RA by a common single nucleotide variant in the KLF4 gene. This KLF4 single-nucleotide variant reportedly induces gastric foveolar epithelial tumorigenesis and activates both cell proliferation and apoptosis, leading to its slow-growing nature. IGD consists of an intestinalized epithelial dysplasia that develops in the pyloric gland mucosa, characterized as a superficial depressed lesion surrounded by raised mucosa showing a gastritis-like appearance. Immunohistochemically, it exhibits an intestinal or gastrointestinal phenotype and, frequently, p53 overexpression. Thus, IGD shows unique characteristics in HpNGNs and a potential multistep tumorigenic process.

Helicobacter pylori-Negative Differentiated Intramucosal Gastric Cancer in the Antrum With a Morphological Change in Four Years: A Case Series

This case report presents two cases of differentiated intramucosal gastric cancer in the antrum. Both patients reported no history of Helicobacter pylori eradication therapy, and endoscopy and diagnostic tests indicated no H. pylori infection. Case 1 is a female patient in her 70s. Esophagoduodenogastroscopy (EGD) detected a depressed lesion. Adenocarcinoma was suspected; thus, endoscopic submucosal dissection (ESD) was performed to resect the lesion. The histological result was well-differentiated tubular adenocarcinoma, which predominantly demonstrated an intestinal mucin phenotype. The existence of a small elevated lesion in the same location was confirmed by reviewing the previous endoscopic record 52 months earlier. Case 2 is a male patient in his 60s in whom screening EGD detected an elevated lesion. The biopsy indicated gastric adenoma, and ESD was performed. The histological diagnosis was well-to-moderately differentiated tubular adenocarcinoma with a pure gastric phenotype. These results indicate that H. pylori-negative differentiated gastric carcinomas in the antrum occur as small elevated lesions that may gradually progress to a depressed form during a relatively long clinical course.

Clinicopathologic differences of gastric neoplasms between Helicobacter pylori-infected and -naïve patients: a multicenter retrospective analysis

BACKGROUND

The incidence of gastric neoplasms in Helicobacter pylori (Hp)-naïve patients has recently increased due to a remarkable decrease in the Hp-infected population in Japan. We investigated the clinicopathologic differences between Hp-infected gastric neoplasms (HpIGNs) and Hp-naïve gastric neoplasms (HpNGNs) that have not been fully elucidated so far.

METHODS

This retrospective multicenter study investigated 966 consecutive patients with 1131 gastric dysplasia or cancers who underwent endoscopic or surgical treatment for the recent decade. Clinicopathologic features were compared between HpIGN and HpNGN cases.

RESULTS

One thousand and sixty-eight HpIGNs in 916 patients included 877 differentiated types and 191 undifferentiated types. Sixty-three HpNGNs in 50 patients included 57 differentiated types (35 foveolar types, 15 intestinal types, 6 fundic-gland types, and 1 other differentiated type) and 6 undifferentiated types. HpNGNs occurred in younger (59.5 vs. 71.8 years, p < 0.05) and female patients (40.0% vs. 26.5%, p < 0.05), were found more frequently in the proximal compartment (p < 0.05), and had smaller size (median 4.0 vs. 20.0 mm, p < 0.05). Histologically, HpNGNs and HpIGNs both primarily consisted of differentiated type (90.5% vs. 82.1%, p = 0.089) and HpNGNs showed lower prevalence of invasive cancer (11.1% vs. 37.6%, p < 0.05) and lymphovascular invasion (1.6% vs. 31.6%, p < 0.05). Nearly all HpNGNs (62/63, 98.4%) were diagnosed in early pathological stage, while 16.1% (172/1068) of HpIGNs were diagnosed in advanced stage (p < 0.05).

CONCLUSIONS

HpNGNs is recently on the increase but shows lower malignant nature regardless of histologic type than HpIGN. Endoscopic gastric cancer screening will be reviewed via cost effectiveness for Hp-naïve individuals in future.

Endoscopic differential diagnosis between foveolar-type gastric adenoma and gastric hyperplastic polyps in Helicobacter pylori-naïve patients

BACKGROUND

Foveolar-type gastric adenoma (FGA) occurs in Helicobacter pylori (Hp)-naïve individuals and morphologically mimics Hp-naïve gastric hyperplastic polyp (HpN-GHP). FGA is often difficult to distinguish from HpN-GHP even by biopsy, due to its low-grade histologic atypia. We conducted a retrospective study to create an endoscopic diagnostic index.

METHODS

We analyzed 51 FGAs in 41 patients and 36 HpN-GHPs in 24 patients. All lesions were photographed by white-light endoscopy (WLE) and narrow-band imaging with magnification endoscopy (NBIME). Three experts and three non-experts reviewed the WLE and WLE+NBIME images to assess six items for lesion diagnosis. We analyzed correlations between the diagnostic items and histologic features and compared the diagnostic accuracy between modalities. We created a composite diagnostic index and calculated its accuracy and consistency.

RESULTS

FGAs more frequently showed the following features vs. HpN-GHPs: bright-red color (94.1% vs. 44.4%), peripheral hyperplasia (58.8% vs. 8.3%), papillary/gyrus-like microstructure (96.1% vs. 33.3%), visible capillaries (70.6% vs. 38.9%), and demarcation line (98.0% vs. 41.7%) (P < 0.05). White-zone thickening was seen only in HpN-GHPs (52.8%). Diagnostic accuracy (mean, WLE vs. WLE+NBIME) was 90.8 ± 1.1% vs. 93.5 ± 2.4% (P = 0.15) for experts and 88.5 ± 3.0% vs. 86.6 ± 3.5% (P = 0.51) for non-experts. When satisfying the four criteria (bright-red color, papillary/gyrus-like microstructure, demarcation line, and absent white-zone thickening), sensitivity and specificity for FGA were 90.2% and 94.4%, respectively, with a kappa value of ≥ 0.6 for interobserver diagnostic agreement.

CONCLUSIONS

Composite diagnostic index contributes to the reproducible, accurate, preoperative differential diagnosis of FGA and HpN-GHP.

Characteristics of different types of Helicobacter pylori: New evidence from non-amplified white light endoscopy

Background

Different types of Helicobacter pylori (H. pylori) were analyzed to determine their infection characteristics using serology, pathology, and non-magnification white light endoscopy combined with the Kimura-Takemoto classification, and the regular arrangement of collecting venules (RAC) as well.

Materials and methods

A retrospective analysis of 685 inpatients who have completed the ¹⁴C-urea breath test, the H. pylori antibody typing classification, the serum gastric function tests (PGI/PGII/G-17), the endoscope detection, and the pathological examinations.

Results

The levels of PGI, PGII, and G-17 were in descending order from the type I H. pylori infection group to the type II H. pylori infection group than the control group (F = 14.31; 26.23; 9.12, P < 0.01). Using the Kimura-Takemoto classification, there were significant differences among the three groups of different degrees of atrophy ( χ 2 =29.81; 482.78; 292.5, P< 0.01). Based on the characteristics of RAC, the H. pylori infection rates were in descending order from the type I H. pylori infection group to the type II H. pylori infection group than the control group ( χ 2 = 200.39; 174.72; 143.51, P < 0.01). The type I H. pylori infection group had higher grades than those of the type II H. pylori infection group in the OLGA and OLGIM staging systems, while the differences are statistically significant only in the OLGA staging system ( χ 2 =10.63, P < 0.05).

Conclusion

With the aid of non-amplified white light endoscopy, we found new evidence of type I H. pylori infection accelerating the progression of gastric mucosal atrophy through the degree of atrophy and the range of infection, whereas type II H. pylori infection has a low ability of migration and atrophy progression. Individual virulence factor-based eradication therapy may be a better choice in future.

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.