Very well-differentiated gastric carcinoma of intestinal type: analysis of diagnostic criteria

Gastric-type extremely well-differentiated adenocarcinoma of the stomach: A rare tumor with diagnostic difficulties and high inter-observer variation in endoscopic pinch biopsies

Extremely well-differentiated gastric-type adenocarcinoma (EWDGA) is a rare type of gastric cancer composed of deceptively bland-looking malignant cells resembling normal foveolar or pyloric epithelium. The histological features of this tumor have not been recognized by many pathologists, and inter-observer variation studies are lacking. Here, we report seven EWDGAs and inter-observer variation of six preoperative biopsies was evaluated by 11 pathologists in a single institute. Based on the pathological diagnosis of the endoscopic biopsy slides, the average rate of definite malignancy diagnosis was 15.2 %, and the overall diagnostic concordance rate was 34.9 % among 11 pathologists. Microscopically, the surface epithelium was preserved and only a few atypical tumor glands were scattered in most endoscopic biopsies. Structural atypia was minimal, and the tumor glands were barely distinguishable from normal glands. Although nuclear atypia was minimal, enlarged nuclei, relatively large glands with irregular shapes, and abundant cytoplasmic mucin were observed in gastric pinch biopsies. In preoperative biopsies, no cases showed p53 overexpression, and Ki-67 labeling index ranged from 3 % to 35 % and was higher compared to non-neoplastic glands in 3 cases. After gastrectomy, four (57.1 %) patients had advanced gastric cancer and three (42.9 %) had lymph node metastasis. Genomic profiling of the four patients revealed mutations of TP53, BRAF, KRAS, STK11, and MDM2/CCND1 amplification. Immunohistochemistry for p53 was not helpful while Ki-67 may be helpful when staining pattern is distinct from the non-neoplastic mucosa. In conclusion, it is challenging to diagnose EWDGA using biopsy specimens. Recognizing and addressing this rare entity will increase diagnostic accuracy to ensure the early diagnosis of cancer.

Long-Term Survival in Metastatic Pancreatic Adenocarcinoma of Intestinal Type

Introduction and Literature Review: Pancreatic cancer is often diagnosed in an advanced/metastatic stage, as it is a very aggressive type of cancer. The prognosis of pancreatic cancer is extremely unfavorable. The mean survival rate for patients with metastatic pancreatic adenocarcinoma is 3-6 months. Stage IV pancreatic cancer has a five-year survival rate of 1.3% to 13%. This article presents recent data regarding the oncologic management of metastatic pancreatic cancer. Case presentation: We present the case of a female patient who was 49 years old at the time of diagnosis, in June 2021. The patient was diagnosed with stage IV pancreatic neoplasm (due to liver metastases). The diagnosis was made by histopathological and immunohistochemical examination, which corroborated imaging investigations. The patient underwent four lines of chemotherapy between July 2021 and July 2024, undergoing partial response to the disease. The patient is a long-term survivor of metastatic pancreatic cancer (3 years in July 2024). Discussions: the peculiarity of this case is long-term survival (3 years and a month at the date when this article is being written) in a patient with pancreatic cancer and liver metastases. Conclusions: histopathological type, good performance status, CEA, and CA tumor markers 19.9 within normal limits may be favorable prognostic factors for long-term survival in metastatic pancreatic carcinoma.

Early gastric cancer with RhoGAP fusion is linked to frequent nodal metastasis and a part of microtubular-mucocellular histology

INTRODUCTION

Gastric cancer with fusion genes involving the Rho GTPase-activating protein domain (RhoGAP-GC) is mainly included in the genomically stable type of The Cancer Genome Atlas classification. Clinical implications and histological characteristics of RhoGAP-GC in the early phase remain unclear.

METHODS

We analyzed 878 consecutive pT1b GCs for RhoGAP and its partner genes using fluorescence in situ hybridization assay.

RESULTS

RhoGAP fusion was detected in 57 (6.5%) GCs. Univariate analysis revealed that female sex, middle-lower third tumor location, advanced macroscopic type, tumor diameter > 2 cm, pT1b2, lymphatic invasion, venous invasion, negative EBER-ISH, and RhoGAP fusion were significantly associated with lymph node metastasis (LNM). Multivariate analysis presented RhoGAP fusion, lymphatic invasion, tumor diameter > 2 cm, advanced macroscopic type, venous invasion, and middle-lower third tumor location as independent risk factors for LNM. Notably, RhoGAP fusion had the highest odds ratio (3.92) for LNM among analyzed parameters (95% CI 2.12-7.27; p < 0.001). Compared to non-RhoGAP-GCs, RhoGAP-GCs were significantly frequent in younger females and showed the highest incidence of lymphatic invasion (56.2%) and LNM (49.1%) (p < 0.001). Histologically, microtubular architecture with pseudo-trabecular interconnection and small aggregations of tumor cells with a varied amount of cytoplasmic mucin, named "microtubular-mucocellular (MTMC) histology," was found in 93.0% (53 of 57) of RhoGAP-GCs in the intramucosal area. MTMC histology showed high sensitivity and negative predictive value (93.0% and 99.4%, respectively) for RhoGAP fusion, albeit positive predictive value is low (34.9%).

CONCLUSION

RhoGAP-GC is linked to a characteristic MTMC histology and a high incidence of LNM.

Mixed adenoma-neuroendocrine tumor of the stomach: analysis of nine cases with literature review

Mixed adenoma-neuroendocrine tumor (MANET) comprises adenoma and well-differentiated neuroendocrine tumor (NET) components. Given the limited information on this due to its rarity, we aimed to clarify the clinicopathologic features and optimal management of gastric MANETs in a case series and literature review. Nine patients with gastric MANETs, including eight male and one female patient (mean age, 72 years), were identified from the institutional pathology archive. Endoscopically, the tumors appeared as flat elevated lesions with sizes ranging from 0.8 to 4.4 cm. One patient had familial adenomatous polyposis, and no patient had autoimmune gastritis. All MANETs developed in the gastric body mucosa exhibiting chronic metaplastic atrophic gastritis. The glandular components were intestinal-type low-grade adenoma, and focal high-grade dysplasia was also recognized in three cases. The NET component was in middle/deep lamina propria in six cases and confined to deep lamina propria in the remaining three cases. Minimal cytologic atypia was found in the NET component, with no recognizable mitosis and a Ki-67 labeling index of < 2%. The NET component mostly showed diffuse positivity for serotonin and CDX2, suggesting that it consists of enterochromaffin cells. Diffuse p53 immunostaining was observed only in the high-grade adenomatous component of one case. No recurrence was observed during the follow-up period of 2-94 months. Correct distinction between the NET and poorly differentiated carcinoma components is crucial to prevent overtreatment of gastric MANETs. Considering its indolent nature, endoscopic resection is the primary recommendation for gastric MANETs as well as for pure adenomas.

Prognostic value analysis and survival model construction of different treatment methods for advanced intestinal type gastric adenocarcinoma

Background

Intestinal-type gastric adenocarcinoma, representing 95 % of gastric malignancies, originates from the malignant transformation of gastric gland cells. Despite its prevalence, existing methods for prognosis evaluation of this cancer subtype are inadequate. This study aims to enhance patient-specific prognosis evaluation by analyzing the clinicopathological characteristics and prognostic risk factors of intestinal-type gastric adenocarcinoma patients using data from the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute (NCI).

Methods

We extracted clinical data for patients diagnosed with intestinal-type gastric adenocarcinoma between 2010 and 2015 from the SEER database, selecting 257 cases based on predefined inclusion and exclusion criteria. Independent risk factors for overall survival (OS) and cancer-specific survival (CSS) were identified using a Cox regression model. A nomogram model for predicting OS or CSS was developed from the Cox risk regression analysis and validated through the consistency index (C-index), ROC curve, and calibration curve.

Results

Age, primary tumor resection, chemotherapy, lymph node metastasis, and tumor size were identified as independent prognostic factors for OS and CSS (P < 0.05). The nomogram model, constructed from these indicators, demonstrated superior predictive consistency for OS and CSS compared to the AJCC-TNM staging system. ROC curve analysis confirmed the model's higher accuracy, and calibration curve analysis indicated good agreement between the nomogram's predictions and actual observed outcomes.

Conclusion

The nomogram model derived from SEER database analyses accurately predicts OS and CSS for patients with intestinal-type gastric adenocarcinoma. This model promises to facilitate more tailored treatments in clinical practice.

Genomic and Pathologic Profiling of Very Well-Differentiated Gastric Adenocarcinoma of Intestinal Type: A Study With Emphasis on Diffuse-Type Transformation

Very well-differentiated adenocarcinoma of intestinal type is a distinct subtype of gastric cancer characterized by anastomosing glands with a hand-in-hand pattern and low-grade cytologic atypia resembling intestinal metaplasia. This is a slow-growing neoplasm with an indolent clinical course; however, a subset demonstrates transformation into adenocarcinoma with higher-grade histology, typically diffuse-type carcinoma, and behaves aggressively. This study aimed to better characterize the genomic and pathologic features, with a focus on factors associated with diffuse-type transformation. A total of 58 cases with (n=31) and without (n=27) diffuse-type transformation were analyzed for molecular and pathologic features. First, comprehensive deep DNA sequencing was conducted in 18 cases (discovery cohort), followed by a digital droplet polymerase chain reaction of hot spot RHOA mutations in 40 cases (validation cohort). In total, RHOA mutations were the most common alteration (34%), followed by loss of ARID1A (12%), p53 alterations (10%), and CLDN18 :: ARHGAP26/6 fusions (3.4%). FGFR2 amplification was identified in an advanced case with a p53 alteration. Altered p53 expression was recognized only in higher-grade components and was significantly associated with advanced disease ( P =0.0015) and diffuse-type transformation ( P =0.026). A mixed mucin phenotype was also strongly correlated with advanced disease ( P <0.001) and diffuse-type transformation ( P <0.001). Decreased E-cadherin expression was frequently observed (74%) in poorly cohesive components. This study demonstrated that a subset of RHOA -mutant diffuse-type gastric cancers develops through the transformation of very well-differentiated adenocarcinoma of intestinal type. Our observations suggest a mixed mucin phenotype as a risk factor and alterations in p53 and E-cadherin as drivers of diffuse-type transformation.

Clinical pathological characteristics of "crawling-type" gastric adenocarcinoma cancer: A case report

BACKGROUND

Gastric cancer (GC) is a significant health problem worldwide, and early detection and accurate diagnosis are crucial for improving patient outcomes. Crawling-type gastric adenocarcinoma is a rare subtype of GC that has unique histopathological and clinical characteristics, and its diagnosis and management can be challenging. This pathological type of GC is also rare.

CASE SUMMARY

Here, we report the case of a patient who underwent ordinary endoscopy, narrow-band imaging, and endoscopic ultrasonography intending to determine the extent of tumor invasion and upper abdominal enhanced computed tomography and whether there was tumor metastasis. Then, endoscopic submucosal dissection was performed. After pathological and immunohistochemical examination, the pathological diagnosis was crawling-type gastric adenocarcinoma. This is a very rare and special pathological type of tumor. This case highlights the importance of using advanced endoscopic techniques and pathological examination in diagnosing and managing gastric crawling-type adenocarcinoma. Moreover, the findings underscore the need for continued research and clinical experience in this rare subtype of GC to improve patient outcomes.

CONCLUSION

The "crawling-type" GC is a rare and specific tumor pathology. It is difficult to identify and diagnose gliomas via endoscopy. The tumor is ill-defined, with a flat appearance and indistinct borders due to the lack of contrast against the background mucosa. Pathology revealed that the tumor cells were hand-like, so the patient has diagnosed with "crawling-type" gastric adenocarcinoma.

Value of quantitative microsurface structure analysis for evaluating the invasion depth of type 0-II early gastric cancer

Background and Aim

The microsurface structure reflects the degree of damage to the glands, which is related to the invasion depth of early gastric cancer. To evaluate the diagnostic value of quantitative microsurface structure analysis for estimating the invasion depth of early gastric cancer.

Methods

White-light imaging and narrow-band imaging (NBI) endoscopy were used to visualize the lesions of the included patients. The area ratio and depth-predicting score (DPS) of each patient were calculated; meanwhile, each lesion was examined by endoscopic ultrasonography (EUS).

Results

Ninety-three patients were included between 2016 and 2019. Microsurface structure is related to the histological differentiation and progression of early gastric cancer. The receiver operating characteristic curve showed that when an area ratio of 80.3% was used as a cut-off value for distinguishing mucosal (M) and submucosal (SM) type 0-II gastric cancers, the sensitivity, specificity, and accuracy were 82.9%, 80.2%, and 91.6%, respectively. The accuracies for distinguishing M/SM differentiated and undifferentiated early gastric cancers were 87.4% and 84.8%, respectively. The accuracy of EUS for distinguishing M/SM early gastric cancer was 74.9%. DPS can only distinguish M-SM1 (SM infiltration <500 μm)/SM (SM infiltration ≥500 μm) with an accuracy of 83.8%. The accuracy of using area ratio for distinguishing 0-II early gastric cancers was better than those of using DPS and EUS (P < 0.05).

Conclusion

Quantitative analysis of microsurface structure can be performed to assess M/SM type 0-II gastric cancer and is expected to be effective for judging the invasion depth of gastric cancer.

Clinicopathological, immunohistochemical and molecular features of acinic cell carcinoma of the breast

Breast acinic cell carcinoma (ACC) is a rare subtype of breast cancer. Accurate diagnosis of ACC using core needle biopsy (CNB) is pivotal for the use of effective treatments and patient prognosis. In the present study, a detailed analysis of the morphological, immunohistochemical and gene mutation features of 2 cases of ACC was performed. CNB was performed prior to surgical excision. The breast ACC in the present cases exhibited overt burrowing labyrinthine networks or 'hand-holding-hand' features. The tumor cells in both of the present cases expressed cytokeratin (CK)7, S100 and CK5/6, but were negative for p63, estrogen receptor and progesterone receptor. GATA binding protein 3 was positive in case 1 but negative in case 2. Fluorescence in situ hybridization indicated no ETS variant transcription factor 6 break-apart probe detection. Next-generation sequencing results revealed the same mutation and a similar abundance in exon 27 (NM_005120.2; c.3817G>T; p.A1273S) of the mediator of RNA polymerase II transcription, subunit 12 homolog (MED12) gene in both patients. To conclude, the findings of the present study suggested that recognition of this rare 'hand-holding-hand' structure could potentially be beneficial for avoiding patient misdiagnosis. In addition, it could be suggested that a mutation in the MED12 exon 27 was associated with the formation of a burrowing labyrinthine network or 'hand-holding-hand' feature.

Mixed crawling-type gastric adenocarcinoma

Crawling-type gastric carcinoma is a rare variant of early gastric carcinoma. Endoscopically, it is a poorly defined tumor with a flat appearance and histologically, especially in a small biopsy, mimic intestinal metaplasia with reactive atypia. We present a case in which, due to the finding of foci of signet ring cell carcinoma, correct management of the patient was carried out.

Unusual or Uncommon Histology of Gastric Cancer

This review comprehensively examines the diverse spectrum of gastric cancers, focusing on unusual or uncommon histology that presents significant diagnostic and therapeutic challenges. While the predominant form, tubular adenocarcinoma, is well-characterized, this review focuses on lesser-known variants, including papillary adenocarcinoma, micropapillary carcinoma, adenosquamous carcinoma, squamous cell carcinoma (SCC), hepatoid adenocarcinoma, gastric choriocarcinoma, gastric carcinoma with lymphoid stroma, carcinosarcoma, gastroblastoma, parietal cell carcinoma, oncocytic adenocarcinoma, Paneth cell carcinoma, gastric adenocarcinoma of the fundic gland type, undifferentiated carcinoma, and extremely well-differentiated adenocarcinoma. Although these diseases have different nomenclatures characterized by distinct histopathological features, these phenotypes often overlap, making it difficult to draw clear boundaries. Furthermore, the number of cases was limited, and the unique histopathological nature and potential pathogenic mechanisms were not well defined. This review highlights the importance of understanding these rare variants for accurate diagnosis, effective treatment planning, and improving patient outcomes. This review emphasizes the need for ongoing research and case studies to enhance our knowledge of these uncommon forms of gastric cancer, which will ultimately contribute to more effective treatments and better prognostic assessments. This review aimed to broaden the pathological narrative by acknowledging and addressing the intricacies of all cancer types, regardless of their rarity, to advance patient care and improve prognosis.

The Role of Mucin Expression in the Diagnosis of Oesophago-Gastric Cancer: A Systematic Literature Review

Survival in oesophago-gastric cancer (OGC) is poor due to early diagnostic challenges. Non-invasive risk stratification may identify susceptible patients with pre-malignant or benign disease. Following diagnostic confirmation with endoscopic biopsy, early OGC may be treated sooner. Mucins are transmembrane glycoproteins implicated in OGC with potential use as biomarkers of malignant transformation. This systematic review defines the role of mucins in OGC diagnosis. A literature search of MEDLINE, Web of Science, Embase and Cochrane databases was performed following PRISMA protocols for studies published January 1960-December 2022. Demographic data and data on mucin sampling and analysis methods were extracted. The review included 124 studies (n = 11,386 patients). Gastric adenocarcinoma (GAc) was the commonest OG malignancy (n = 101) followed by oesophageal adenocarcinoma (OAc, n = 24) and squamous cell carcinoma (OSqCc, n = 10). Mucins MUC1, MUC2, MUC5AC and MUC6 were the most frequently implicated. High MUC1 expression correlated with poorer prognosis and metastases in OSqCc. MUC2 expression decreases during progression from healthy mucosa to OAc, causing reduced protection from gastric acid. MUC5AC was upregulated, and MUC6 downregulated in GAc. Mucin expression varies in OGC; changes may be epigenetic or mutational. Profiling upper GI mucin expression in OGC, with pre-malignant, benign and healthy controls may identify potential early diagnostic biomarkers.

Association of CDX2 and mucin expression with chemotherapeutic benefits in patients with stage II/III gastric cancer

BACKGROUND

Better predictors of patients with stage II/III gastric cancer (GC) most likely to benefit from adjuvant chemotherapy are urgently needed. This study aimed to assess the ability of CDX2 and mucin markers to predict prognosis and fluorouracil-based adjuvant chemotherapy benefits.

METHODS

CDX2 and mucin protein expressions were examined by immunohistochemistry and compared with survival and adjuvant chemotherapy benefits in a prospective evaluation cohort of 782 stage II/III GC patients. Then, the main findings were validated in an independent validation cohort (n = 386) and an external mRNA sequencing dataset (ACRG cohort, n = 193).

RESULTS

In the evaluation cohort, CDX2, CD10, MUC2, MUC5AC, and MUC6 expressions were observed in 59.7%, 26.7%, 27.6%, 55.1%, and 57.7% of patients, respectively. However, only the expression of CDX2 was found to be associated with adjuvant chemotherapy benefits. Most importantly, CDX2-negative patients had a poorer prognosis when treated with surgery only, while the prognosis of CDX2-negative and CDX2-positive patients was similar when receiving postoperative adjuvant chemotherapy. Further analysis revealed that patients with CDX2 negative tumors benefited from chemotherapy (5-year overall survival rates: 60.0% with chemotherapy vs. 23.2% with surgery-only, p < 0.001), whereas patients with CDX2 positive tumors did not (pinteraction  = 0.004). Consistent results were obtained in the validation and ACRG cohorts.

CONCLUSIONS

Negative expression of CDX2 is an independent risk factor for survival in stage II/III GC, but subsequent adjuvant chemotherapy is able to compensate for this unfavorable effect. Therefore, active chemotherapy is more urgent for patients with negative CDX2 expression than for patients with positive CDX2 expression.

Further prognostic stratification of intestinal type of gastric adenocarcinoma by CDX2 expression pattern

Gastric cancer is one of the most deadly malignancies worldwide. It is routinely divided into 2 common histologic subtypes by the Lauren classification, intestinal type and diffuse type. In recent years, the intestinal type of gastric cancer has been found to represent a heterogeneous disease with divergent prognosis. Our objective was to investigate the CDX2/CK7 immunohistochemical pattern and its role in further stratifying this type of gastric cancer. Gastrectomy cases with a diagnosis of the intestinal type of gastric adenocarcinoma from a single large institution between 2008 and 2022 were collected. Forty-four cases with available blocks and enough tumor tissue were included in this study. Four different immunohistochemical patterns were identified: CDX2+/CK7+ (40.9%), CDX2-/CK7+ (34.1%), CDX2+/CK7- (18.2%), and CDX2-/CK7- (6.8%). Compared to CDX2-negative cases, CDX2-positive ones are more likely to present better prognostic histopathological features including early stage, less perineural and lymphovascular invasion, and lower nodal metastasis. In addition, CDX2 expression was associated with specific molecular features like HER2 overexpression and genetic alterations of receptor tyrosine kinase (TRK) genes including EGFR, ERBB2, ERBB3, DDR2, and MET. In conclusion, according to the CDX2 expression pattern, the intestinal type of gastric cancer could be further divided into 2 subgroups, which have different histopathological and molecular features and different prognosis.

Superficial spreading type of early gastric cancer with diagnostic difficulty and positive surgical margin: a case report

An 83-year-old man visited our hospital because of difficulty swallowing. Gastroscopy revealed multiple ulcers and a reddish depression in the lesser curvature of the middle stomach. The initial biopsy showed regenerative atypia, so a gastroscopy was repeated every 3 months thereafter because of suspected malignancy. A biopsy performed 12 months after the initial gastroscopy revealed a well-differentiated adenocarcinoma. After determination of the planned oral resection line by two negative biopsies, laparoscopic distal gastrectomy was performed. The resected specimen showed a 0 - IIa + IIc lesion composed of well-to-moderately differentiated tubular adenocarcinoma, including hand-shaking-type gastric cancer. The oral resection margin was positive due to widespread mucosal extension; therefore, an additional total gastrectomy was needed. Cases of well-differentiated adenocarcinoma and its superficial extension may be difficult to diagnose via endoscopy and biopsy.

Claudins and Gastric Cancer: An Overview

Simple Summary

Gastric cancer (GC) is one of the most common cancers and the third leading cause of cancer deaths worldwide, with a high frequency of recurrence and metastasis, and a poor prognosis. This review presents novel biological and clinical significance of claudin (CLDN) expression in GC, especially CLDN18, and clinical trials centered around CLDN18.2. It also presents new findings for other CLDNs.

Abstract

Despite recent improvements in diagnostic ability and treatment strategies, advanced gastric cancer (GC) has a high frequency of recurrence and metastasis, with poor prognosis. To improve the treatment results of GC, the search for new treatment targets from proteins related to epithelial–mesenchymal transition (EMT) and cell–cell adhesion is currently being conducted. EMT plays an important role in cancer metastasis and is initiated by the loss of cell–cell adhesion, such as tight junctions (TJs), adherens junctions, desmosomes, and gap junctions. Among these, claudins (CLDNs) are highly expressed in some cancers, including GC. Abnormal expression of CLDN1, CLDN2, CLDN3, CLDN4, CLDN6, CLDN7, CLDN10, CLDN11, CLDN14, CLDN17, CLDN18, and CLDN23 have been reported. Among these, CLDN18 is of particular interest. In The Cancer Genome Atlas, GC was classified into four new molecular subtypes, and CLDN18–ARHGAP fusion was observed in the genomically stable type. An anti-CLDN18.2 antibody drug was recently developed as a therapeutic drug for GC, and the results of clinical trials are highly predictable. Thus, CLDNs are highly expressed in GC as TJs and are expected targets for new antibody drugs. Herein, we review the literature on CLDNs, focusing on CLDN18 in GC.

Clinical and phenotypical characteristics of submucosal invasive carcinoma in non-ampullary duodenal cancer

Objective

The rare incidence of submucosal invasive non-ampullary duodenal carcinoma has led to scant information in literature; therefore, we compared the clinicopathological features between submucosal invasive carcinoma (SM-Ca), mucosal carcinoma (M-Ca), and advanced carcinoma (Ad-Ca).

Materials

We retrospectively analyzed 165 patients with sporadic non-ampullary duodenal carcinomas (SNADCs) from four institutions between January 2003 and December 2018. The SNADCs were divided to three groups according to histological diagnosis: SM-Ca, M-Ca, and Ad-Ca. The clinicopathological characteristics and mucin phenotypes were compared between groups.

Results

Among the 165 SNADCs, 11 (7%) were classified as SM-Ca, 70 (42%) as M-Ca, and 84 (51%) as Ad-Ca. We found that all SM-Ca (P = 0.013) and most Ad-Ca (P = 0.020) lesions were located on the oral-Vater; however, an almost equal distribution of M-Ca lesions was found between the oral- and anal-Vater. No significant difference was observed between the tumor diameter of M-Ca and SM-Ca; however, 45% (5/11) of SM-Ca were ≤10 mm. A total of 73% (8/11) of SM-Ca were classified as gastric phenotype and no lesions were classified as intestinal phenotype; whereas most M-Ca were classified as intestinal phenotype (67%, 8/12).

Conclusions

SM-Ca lesions were all located on the oral-Vater and were highly associated with the gastric mucin phenotype, which were different from the features of most M-Ca.

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.

Risk-Scoring System for Prediction of Non-Curative Endoscopic Submucosal Dissection Requiring Additional Gastrectomy in Patients with Early Gastric Cancer

Purpose

When patients with early gastric cancer (EGC) undergo non-curative endoscopic submucosal dissection requiring gastrectomy (NC-ESD-RG), additional medical resources and expenses are required for surgery. To reduce this burden, predictive model for NC-ESD-RG is required.

Materials and Methods

Data from 2,997 patients undergoing ESD for 3,127 forceps biopsy-proven differentiated-type EGCs (2,345 and 782 in training and validation sets, respectively) were reviewed. Using the training set, the logistic stepwise regression analysis determined the independent predictors of NC-ESD-RG (NC-ESD other than cases with lateral resection margin involvement or piecemeal resection as the only non-curative factor). Using these predictors, a risk-scoring system for predicting NC-ESD-RG was developed. Performance of the predictive model was examined internally with the validation set.

Results

Rate of NC-ESD-RG was 17.3%. Independent pre-ESD predictors for NC-ESD-RG included moderately differentiated or papillary EGC, large tumor size, proximal tumor location, lesion at greater curvature, elevated or depressed morphology, and presence of ulcers. A risk-score was assigned to each predictor of NC-ESD-RG. The area under the receiver operating characteristic curve for predicting NC-ESD-RG was 0.672 in both training and validation sets. A risk-score of 5 points was the optimal cut-off value for predicting NC-ESD-RG, and the overall accuracy was 72.7%. As the total risk score increased, the predicted risk for NC-ESD-RG increased from 3.8% to 72.6%.

Conclusions

We developed and validated a risk-scoring system for predicting NC-ESD-RG based on pre-ESD variables. Our risk-scoring system can facilitate informed consent and decision-making for preoperative treatment selection between ESD and surgery in patients with EGC.

Novel Pathologic Factors for Risk Stratification of Gastric "Indefinite for Dysplasia" Lesions

Methods

In total, 123 IND cases with final diagnoses of cancer (29.3%), high-grade dysplasia (6.5%), low-grade dysplasia (11.4%), and nonneoplasm (52.8%) were randomly divided into test set (n = 27) and validation set (n = 96). By the image analysis, size, pleomorphism, hyperchromasia, irregularity of nuclei, and ratios of structural atypia area (SAA) to total IND area were measured in the test set. Using the validation set, consensus meetings were held for the evaluation of pathologic factors that predict the final diagnosis.

Results

By image analysis, the only ratio of SAA to total IND area was associated with the final diagnosis (p < 0.001). In the consensus meeting for validation, the nuclear factors, except loss of nuclear polarity (p = 0.004–0.026), could not predict the final diagnosis. Conversely, most structural factors could predict the final diagnosis. In particular, SAA > 25% was the most powerful predictive factor. We proposed criteria of risk stratification by using SAA > 25%, loss of surface maturation (LOSM), and loss of nuclear polarity (LONP) (Malignancy rate; Category 0: SAA ≤ 25% without LOSM and LONP; 0%, Category 1: SAA ≤ 25% with any of LOSM or LONP; 15.2%–16.7%, Category 2: SAA > 25% without LOSM and LONP; 44.4%–50.0%, Category 3: SAA > 25% with any of LOSM or LONP 54.5%–55.6%).

Conclusions

Structural atypia was more helpful than nuclear atypia and SAA > 25% was the most powerful predictor for the diagnosis of INDs of the stomach. We propose shortening the follow-up period to six months for Category 1, endoscopic resection for Category 2 and 3, postresection follow-up periods of one year for Category 2, and six months for Category 3.

Analysis of clinicopathological and molecular features of crawling-type gastric adenocarcinoma

BACKGROUND

Crawling-type adenocarcinoma (CRA) is an important gastric cancer (GC) subtype that exhibits a specific histological pattern and has characteristic clinicopathological findings. Despite its characteristic histology, little is known about the molecular characteristics of CRA.

METHODS

We examined 177 GC cases, including 51 cases of CRA and 126 cases having conventional differentiated adenocarcinomas (CDAs). Results for immunohistochemistry (mucin phenotype; Muc5AC, Muc6, Muc2 and CD10, CDX-2, MLH-1, p53 and β-catenin), mutation analysis (TP53, KRAS and BRAF), microsatellite instability (BAT25, BAT26, D2S123, D5S346 and D17S250), DNA methylation status by a two-panel method (RUNX3, MINT31, LOX, NEUROG1, ELMO1 and THBD), MLH-1 promoter methylation, and allelic imbalance (AI; 1p, 3p, 4p, 5q, 8p, 9p, 13q, TP53, 18q and 22q) were examined.

RESULTS

CRAs were more likely to occur in the middle third of the stomach, in younger patients and to be macroscopically depressed. Nuclear accumulation of β-catenin and loss of MLH-1 expression were less frequent among CRA cases compared to CDA cases. At a molecular level, CRA is often characterized by the deletion mutation c.529_546 (18-base pair deletion at codon 177-182 in exon 5) in the TP53 gene (10 cases). Although the low methylation epigenotype was significantly more frequent for CRAs compared to CDAs, multiple AIs were more often seen in CRAs relative to CDAs.

CONCLUSIONS

The results demonstrated that TP53 mutations, particularly c.529_546del, and multiple AIs are closely associated with CRA carcinogenesis. Our results suggest that CRA is an independent entity of GC in terms of clinicopathologic and molecular findings.

Preoperative diagnosis of a gastric extremely well-differentiated adenocarcinoma: A case report

•

Gastric extremely well-differentiated adenocarcinoma (EWDA) is a rare type of gastric adenocarcinoma.

•

It is very difficult to preoperatively diagnose gastric EWDA presenting as an elevated lesion appearing like a submucosal tumor.

•

This is the first report of a gastric EWDA appearing like a submucosal tumor diagnosed by preoperative endoscopic submucosal dissection.

Introduction

Gastric adenocarcinomas with low grade atypia may be difficult to diagnose as gastric cancer by preoperative biopsy. We report an extremely well-differentiated adenocarcinoma (EWDA) of the stomach which appeared like a submucosal tumor diagnosed by preoperative endoscopic submucosal dissection.

Presentation of case

A 70-year-old male was referred with a 3-month history of a submucosal-appearing lesion in the gastric wall found on endoscopy. Biopsies of the lesion were performed and were inconclusive for neoplasia. Endoscopic ultrasonography showed a low echoic tumor growing into the fourth layer of the gastric wall. It was difficult to identify the tumor by repeat biopsy. Endoscopic submucosal dissection of the lesion was performed and revealed adenocarcinoma, and laparoscopic total gastrectomy was performed. Histopathologic evaluation showed that the tumor was stage IIA (T3N0M0). There is no recurrence 12 months after resection.

Discussion

Gastric EWDAs are rare lesions, accounting for 0.6% of all gastric cancers. It is difficult to diagnose gastric EWDA especially if it appears like a submucosal tumor. This lesion was finally diagnosed by endoscopic submucosal dissection.

Conclusion

Endoscopic submucosal dissection may facilitate establishing the preoperative diagnosis of a tumor thought to be a gastric EWDA based on its endoscopic appearance and pathological findings.

Clinicopathological features of early gastric cancers arising in Helicobacter pylori uninfected patients

BACKGROUND

Persistent Helicobacter pylori (H. pylori) infection causes chronic inflammation, atrophy of the gastric mucosa, and a high risk of developing gastric cancer. In recent years, awareness of eradication therapy has increased in Japan. As H. pylori infections decrease, the proportion of gastric cancers arising from H. pylori uninfected gastric mucosa will increase. The emergence of gastric cancer arising in H. pylori uninfected patients though rarely reported, is a concern to be addressed and needs elucidation of its clinicopathological features.

AIM

To evaluate the clinicopathological features of early gastric cancer in H. pylori-uninfected patients.

METHODS

A total of 2462 patients with 3375 instances of early gastric cancers that were treated by endoscopic submucosal dissection were enrolled in our study between May 2000 and September 2019. Of these, 30 lesions in 30 patients were diagnosed as H. pylori-uninfected gastric cancer (HpUIGC). We defined a patient as H. pylori-uninfected using the following three criteria: (1) The patient did not receive treatment for H. pylori, which was determined by investigating medical records and conducting patient interviews; (2) Lack of endoscopic atrophy; and (3) The patient was negative for H. pylori after being tested at least twice using various diagnostic methods, including serum anti-H. pylori-IgG antibody, urease breath test, rapid urease test, and microscopic examination.

RESULTS

The frequency of HpUIGC was 1.2% (30/2462) for the patients in our study. The study included 19 males and 11 females with a mean age of 59 years. The location of the stomach lesions was divided into three sections; upper third (U), middle third (M), lower third (L). Of the 30 lesions, 15 were U, 1 was M, and 14 were L. Morphologically, 17 lesions were protruded and flat elevated type (0-I, 0-IIa, 0-IIa + IIc), and 13 lesions were flat and depressed type (0-IIb, 0-IIc). The median tumor diameter was 8 mm (range 2-98 mm). Histological analysis revealed that 22 lesions (73.3%) were differentiated type.The HpUIGC lesions were classified into fundic gland type adenocarcinoma (7 cases), foveolar type well-differentiated adenocarcinoma (8 cases), intestinal phenotype adenocarcinoma (7 cases), and pure signet-ring cell carcinoma (8 cases). Among 30 HpUIGCs, 24 lesions (80%) were limited to the mucosa; wherein, the remaining 6 lesions showed submucosal invasion. One of the submucosal invasive lesions showed more than 500 μm invasion. The mucin phenotype analysis identified 7 HpUIGC with intestinal phenotype and 23 with gastric phenotype.

CONCLUSION

We elucidated the clinicopathological characteristics of HpUIGC, revealing recognition not only undifferentiated-type but also differentiated-type. In addition, intestinal phenotype tumors were also observed and could be an important tip.

miR-99a-5p as Possible Diagnostic and Prognostic Marker in Patients With Gastric Cancer

BACKGROUND

The signet-ring cell carcinoma (SRC), one of the histological subtypes of gastric cancer, often exhibits aggressive behavior in clinical practice and is therefore a commonly found subtype in advanced gastric cancer. However, SRC, especially at the early stages, has recently been reported to show a lower potential for malignancy than other pathological subtypes. Because the detailed molecular mechanisms underlying SRC pathology remain unclear, we focused on microRNAs (miRs) and aimed to elucidate the molecular mechanisms involved in endowing early SRC with its characteristic properties.

MATERIALS AND METHODS

Formalin-fixed paraffin-embedded samples of patients diagnosed with various pathological subtypes of gastric cancer including SRC were used to purify and subsequently evaluate miRs.

RESULTS

As expected, patients with SRC were observed to have significantly high miR-99a-5p expression. Further, high miR-99a-5p expression was found to closely correlate with less aggressive clinicopathological features, and functional studies probed by overexpression of miR-99a-5p resulted in inhibition of proliferation in two SRC cell lines.

CONCLUSIONS

The present study reports that high levels of miR-99a-5p were observed in patients with SRC, particularly those with early stage SRC. In addition, miR-99a-5p expression was found to be related to cell proliferation. Therefore, miR-99a-5p could emerge as a diagnostic biomarker for early SRC and lymph node metastases or related adverse prognosis in patients.

Outcomes of endoscopic submucosal dissection for intestinal-type adenocarcinoma with anastomosing glands of the stomach

BACKGROUND AND AIM

Gastric intestinal-type adenocarcinoma with anastomosing glands (IAAG) is characterized by architectural abnormality with frequent anastomosing glands and low-grade cytologic atypia. Clinicopathologic features and long-term outcomes of endoscopic submucosal dissection (ESD) for IAAG remain unclear.

METHODS

This study included 2828 patients who underwent ESD for early gastric cancers (EGCs) (78 IAAGs [2.6%] and 2893 well-differentiated [WD] or moderately differentiated [MD] EGCs [97.4%]). Clinicopathologic features and short-term and long-term outcomes of ESD for IAAG were reviewed and compared with those for WD or MD EGCs.

RESULTS

Gastric IAAGs were larger and more likely to be confined to the lamina propria than WD or MD EGCs. Histological heterogeneity, flat or depressed lesion and lateral resection margin (LRM) involvement were observed with significantly higher frequencies in IAAGs than in WD or MD EGCs. En bloc with R0 resection and curative resection rates of IAAGs were 79.5% and 73.1%, respectively, and both were significantly lower than those of WD or MD EGCs (93.8% and 82.9%). LRM involvement accounted for 57.1% of the non-curative resection cases in gastric IAAGs. Half of IAAGs with LRM involvement had a crawling pattern at tumor periphery. Among patients undergoing curative ESD for IAAG, no recurrences occurred during a median 52 months of follow-up. No lymph node metastasis was found in any of IAAG patients undergoing additional surgery after ESD.

CONCLUSIONS

Gastric IAAGs have distinct clinicopathologic features from WD or MD EGCs. Given the favorable long-term outcomes after curative resection, ESD can be indicated for early gastric IAAGs.

RHOA mutations and CLDN18-ARHGAP fusions in intestinal-type adenocarcinoma with anastomosing glands of the stomach

A subtype of intestinal-type adenocarcinoma of the stomach, characterized by low-grade cytological atypia and anastomosing glands, has been described in several reports under different names. One of the remarkable features of these lesions, herein referred to as intestinal-type adenocarcinoma with anastomosing glands, is the frequent association of poorly differentiated adenocarcinoma components. Here we analyzed 44 intestinal-type adenocarcinomas with anastomosing glands focusing on the molecular abnormalities that are common in diffuse-type gastric cancers. Next-generation sequencing identified RHOA and CDH1 mutations in 22 (50%) and one lesion (2%), respectively. Reverse transcription-PCR detected CLDN18-ARHGAP fusions in three lesions (7%). Immunohistochemically, none of the lesions showed abnormal p53 expression patterns whereas focal and diffuse loss of ARID1A was observed in four and one lesion, respectively. Examination of 37 lesions of dysplasia and 26 usual-type intramucosal adenocarcinomas identified one RHOA mutation in adenocarcinoma and no CLDN18-ARHGAP fusions, indicating that these genetic alterations are highly specific to intestinal-type adenocarcinomas with anastomosing glands among differentiated-type intramucosal neoplasms. The present study showed that intestinal-type adenocarcinoma with anastomosing glands represents a genetically distinct group of tumors with the frequent presence of RHOA mutations and CLDN18-ARHGAP fusions, which are thought to be specific to diffuse-type gastric cancers.

Treatment for gastric ‘indefinite for neoplasm/dysplasia’ lesions based on predictive factors

BACKGROUND

Gastric ‘indefinite for neoplasm/dysplasia’ (IFND) is a borderline lesion that is difficult to diagnose as either regenerative or neoplastic. There is a need for guidance in the identification of a subset of patients, who have an IFND lesion with a higher risk of malignant potential, to enable risk stratification and optimal management.

AIM

To determine the clinical and pathologic factors for the accurate diagnosis of gastric IFND lesions.

METHODS

In total, 461 gastric lesions diagnosed via biopsy as IFND lesions were retrospectively evaluated. Endoscopic resection (n = 134), surgery (n = 22), and follow-up endoscopic biopsy (n = 305) were performed to confirm the diagnosis. The time interval from initial biopsy to cancer diagnosis was measured, and diagnostic delays were categorized as > 2 wk, > 2 mo, > 6 mo, and > 1 year. The IFND lesions presenting as regenerating atypia (60%) or atypical epithelia (40%) at initial biopsy were adenocarcinomas in 22.6%, adenomas in 8.9%, and gastritis in 68.5% of the cases.

RESULTS

Four clinical factors [age ≥ 60 years (2.445, 95%CI: 1.305-4.580, P = 0.005), endoscopic size ≥ 10 mm (3.519, 95%CI: 1.891-6.548, P < 0.001), single lesion (5.702, 95%CI: 2.212-14.696, P < 0.001), and spontaneous bleeding (4.056, 95%CI: 1.792-9.180, P = 0.001)], and two pathologic factors [atypical epithelium (25.575, 95%CI: 11.537-56.695, P < 0.001], and repeated IFND diagnosis [6.022, 95%CI: 1.822-19.909, P = 0.003)] were independent risk factors for gastric cancer. With two or more clinical factors, the sensitivity and specificity for carcinoma were 91.3% and 54.9%, respectively. Ten undifferentiated carcinomas were initially diagnosed as IFND. In the subgroup analysis, fold change (5.594, 95%CI: 1.458-21.462, P = 0.012) predicted undifferentiated or invasive carcinoma in the submucosal layers or deeper. Diagnostic delays shorter than 1 year were not associated with worse prognoses. Extremely well-differentiated adenocarcinomas accounted for half of the repeated IFND cases and resulted in low diagnostic accuracy even on retrospective blinded review.

CONCLUSION

More than two clinical and pathologic factors each had significant cut-off values for gastric carcinoma diagnosis; in such cases, endoscopic resection should be considered.

Expression of Gastric Markers Is Associated with Malignant Potential of Nonampullary Duodenal Adenocarcinoma

BACKGROUND

Sporadic nonampullary duodenal epithelial tumors (NADETs) are uncommon, and thus their clinicopathological features have not been fully assessed.

AIMS

In this study, we have analyzed a series of early sporadic NADETs, focusing on various immunohistological features.

METHODS

We conducted a multicenter retrospective analysis of 68 patients with endoscopically resected sporadic NADETs. Associations between immunohistological features and clinicopathological features were statistically analyzed.

RESULTS

The 68 patients consisted of 46 men (68%) and 22 women (32%) with a mean age of 60.7 ± 12.2 years (range 37-85 years). The 68 tumors were composed of 39 adenomas (57%) and 29 early-stage adenocarcinomas (43%). Duodenal adenocarcinomas were larger in size than adenomas and had papillary architecture in their pathological diagnosis with statistical significance. Duodenal adenocarcinomas also demonstrated a significantly higher expression of gastric markers (MUC5AC and MUC6) and a higher MIB-1 index. Duodenal adenomas were contrastively apt to express intestinal markers (MUC2, CDX1 and CDX2). Of the 68 cases analyzed, there were only 3 tumors positive for p53 staining, all of which were adenocarcinoma. When 7 submucosal invasive cancers and 21 intramucosal cancers were compared, submucosal invasion was positively associated with expression of MUC5AC. Also, submucosal invasion showed strong association with double-positivity of MUC5AC and MUC6.

CONCLUSIONS

Our results indicate that immunohistochemical evaluation is useful for predicting malignant potential of NADETs, especially focusing on the expression of gastrointestinal markers.

Well-differentiated adenocarcinoma may be misdiagnosed as gastritis cystica profunda

Gastric cancer (GC) is one of the most common malignant tumors in China. The low detection rate of early GC is one of the reasons for its high mortality rate. Thanks to the application of new gastroscopy technology, the detection rate of early GC has increased. Highly differentiated adenocarcinoma accounts for about 70% of all early GC cases; however, well-differentiated adenocarcinoma is difficult to diagnose because of its non-significant structural abnormality and cellular atypia. Gastritis cystica profunda is a rare disease characterized by the presence of the gastric intrinsic gland in the muscularis mucosa and/or submucosa, which is easily confused with highly differentiated adenocarcinoma. Therefore, attention should be paid to the identification of these two different entities in the clinical work.

Distinct expression profile of key molecules in crawling-type early gastric carcinoma

BACKGROUND

Gastric "crawling-type" adenocarcinoma (CRA) is a tumor histologically characterized by irregularly fused glands with low-grade cellular atypia that tends to spread laterally in the mucosa. To date, the expression characteristics of the key molecules involved in CRA, including receptor tyrosine kinases (RTKs), mismatch repair (MMR) proteins, phosphatase and tensin homolog (PTEN), as well as the Epstein-Barr virus (EBV) status, have yet to be uncovered.

METHODS

We constructed tissue microarrays of 94 CRAs, 72 conventional-type differentiated adenocarcinomas (CDAs), and 71 intramucosal poorly cohesive adenocarcinomas (PCAs) from early gastric cancers to evaluate and compare the pathological and expression profiles of potential key molecules for molecular classification (EBV; four MMR proteins-MLH1, MSH2, PMS2, and MSH6; three RTKs-HER2, MET, and EGFR; PTEN; and p53).

RESULTS

None of the CRAs showed MMR deficiency (0.0 % vs. 5.6 %, CRA vs. CDA, p = 0.036), HER2 overexpression (0.0 % vs. 12.5 %, p = 0.001), or loss of PTEN expression (0.0 % vs. 9.7 %, p = 0.003). Moreover, MET overexpression (4.4 % vs. 19.4 %, p = 0.004), and a mutant p53 pattern (12.4 % vs. 62.5 %, p < 0.001) were significantly less common in CRAs than in CDAs. However, clinicopathological features and all the profile of the molecules of CRAs were close to those of the PCA group.

CONCLUSIONS

CRA demonstrated unique clinicopathological characteristics and showed a distinct expression profile of key molecules, which was close to that of a null phenotype. These results support the classification of CRA as a distinct subgroup of gastric adenocarcinoma.

计算机深度学习与智能图像诊断对胃高分化腺癌病理诊断的价值

随着计算机技术的发展, 机器学习被深入研究并应用到各个领域, 机器学习在医学中的应用将转换现在的医学模式, 利用机器学习处理医学中庞大数据可提高医生诊断准确率, 指导治疗, 评估预后. 机器学习中的深度学习已广泛应用在病理智能图像诊断方面, 目前在有丝分裂检测, 细胞核的分割和检测, 组织分类中已取得较好成效. 在病理组织学上, 胃高分化腺癌因其组织结构和细胞形态异型性小, 取材标本表浅等原因容易漏诊. 现有的早期胃癌的病理智能图像诊断系统中没有关于腺腔圆度的研究, 圆度测量可以将腺腔结构的不规则, 腺腔扩张等特征转换为具体数值的定量指标, 通过数值大小来进行诊断分析, 为病理诊断提供参考价值.

Clinicopathology of Early Gastric Carcinoma: An Update for Pathologists and Gastroenterologists

BACKGROUND

The WHO defines early gastric carcinoma (EGC) as invasive carcinoma up to the submucosal layer, regardless of nodal metastasis. The recent study results indicate that EGC varies in location, histology, nodal metastasis, and prognosis.

SUMMARY

The heterogeneity in EGC may be related to various types of epithelial stem cells. The most important stem cells include Lgr5+ cells at the base of a gastric unit in the antrum-pylorus-cardia, Mist1+ cells at the isthmus/Troy+ cells at the base in the corpus-fundus, and Sox2+ cells at the base in almost all regions. Dysregulation of these cells along with environmental factors transform stem cells in different regions into malignancy in genetically susceptible populations.

KEY MESSAGE

The 2 most vulnerable regions for EGC have been found along the lesser curvature: the cardia in elderly patients and antrum-angularis in mid-aged and elderly patients. Most hereditary early-onset gastric carcinomas are concentrated in the corpus-fundus of young women. By histology, the most common EGC type is tubular adenocarcinoma in many growth patterns, starting in the neck of a gastric unit. Worse prognosis has been found in early papillary, compared to tubular, adenocarcinoma, related to deeper penetration, more lymphovascular invasion, and more liver and nodal metastases. Contrary to the common belief, intramucosal signet ring cell carcinoma demonstrates low risk of nodal metastasis, comparable to early intestinal-type EGC.

PRACTICAL IMPLICATIONS

The overall risk for nodal metastasis in EGC is low but significant. It is urgent to organize multicenter studies on risk of nodal metastasis in EGC in order to establish more reliable clinical practice guidelines to treat EGC patients.

The Japanese Viewpoint on the Histopathology of Early Gastric Cancer

Japanese histopathologists have traditionally had greater opportunity to study the histology and clinical course of early gastric cancer because of technological developments including double contrast radiography and endoscopy systems, combined with the higher incidence of gastric cancer in the general population in Japan. Endoscopic resection is now considered best practice for treatment of early gastric cancers with a negligible risk of lymph node metastasis. Histopathologic evaluation plays a critical role in assessing the likelihood of lymph node metastasis on endoscopically resected specimens. There remains disparity between Western and Japanese histopathologists in the conceptual approach to the histopathologic evaluation of neoplastic lesions in the upper gastrointestinal tract, in particular regarding lesions straddling the borderline between noninvasive and invasive disease. Although in routine practice, the clinical impact of these conceptual differences is small, this disparity does complicate international exchange of datasets and the development of globally applicable formal definitions. Here we review the current practice in histological diagnosis of early gastric cancer in Japan and discuss some of the conceptual differences between Japanese and Western histopathological assessment of lesions in the neoplastic stomach.

Risk factors for under-diagnosis of gastric intraepithelial neoplasia and early gastric carcinoma in endoscopic forceps biopsy in comparison with endoscopic submucosal dissection in Chinese patients

Differences in pathologic diagnosis between endoscopic forceps biopsy (EFB) and endoscopic submucosal dissection (ESD) for gastric intraepithelial neoplasia (GIN) and early gastric carcinoma (EGC) in Chinese patients remain unknown. The aim of the study was to investigate risk factors for under-diagnosed pathology in initial EFB, compared to final ESD. We reviewed endoscopic and histopathologic findings for tumor location, size, macroscopic pattern, nodularity, erythema, erosion, GIN (low and high grade), and EGC diagnosed with the WHO criteria. Differences in those features between EFB and ESD were compared and risk factors for under-diagnosis by EFB were analyzed. Although concordant in most (74.9 %) cases between EFBs and ESDs, pathological diagnoses in 57 (25.1 %) cases were upgraded in ESDs. Compared to the concordant group, the lesion size ≥2 cm, and depressed and excavated patterns were significantly more frequent in the upgraded group. Further multivariate regression analysis demonstrated the depressed pattern and lesion size ≥2 cm as independent risk factors for upgraded pathology with the odds ratio of 5.778 (95 % confidence interval 2.893-11.542) and 2.535 (95 % confidence interval 1.257-5.111), respectively. Lesion size ≥2.0 cm and the depressed pattern at initial EFB were independent risk factors for pathologic upgrade to advanced diseases in ESD. Therefore, these endoscopic characteristics should be considered together with the initial EFB diagnosis to guide the optimal clinical management of patients with GIN and EGC.

Gastric-Type Extremely Well-Differentiated Adenocarcinoma of the Stomach: A Challenge for Preoperative Diagnosis

Gastric-type extremely well-differentiated adenocarcinoma (EWDA) is a rare type of gastric adenocarcinoma characterized by infiltration of well-formed mucinous glands with little or no nuclear atypia, which resemble foveolar epithelium or pyloric glands. Because of its high degree of differentiation, preoperative biopsy diagnosis of gastric-type EWDA is very difficult. We encountered a case of gastric-type EWDA, manifesting as a Borrmann type 4 lesion, in a 47-year-old man. Despite four repeated biopsies, the preoperative biopsy diagnosis was not conclusive due to the scarcity of diagnostic tumor cells and lack of knowledge regarding the unusual histologic findings of gastric-type EWDA. We herein describe the histologic findings of gastric-type EWDA in detail, with the aim of facilitating a preoperative biopsy diagnosis and understanding of this rare type of gastric adenocarcinoma.