Artificial Intelligence-Based Diagnosis of Gastric Mesenchymal Tumors Using Digital Endosonography Image Analysis.

Background/Objectives: Artificial intelligence (AI)-assisted endoscopic ultrasonography (EUS) diagnostic tools have shown excellent performance in diagnosing gastric mesenchymal tumors. This study aimed to assess whether incorporating clinical and endoscopic factors into AI-assisted EUS classification models based on digital image analysis could improve the diagnostic performance of AI-assisted EUS diagnostic tools. Methods: We retrospectively analyzed the data of 464 patients who underwent both EUS and surgical resection of gastric mesenchymal tumors, including 294 gastrointestinal stromal tumors (GISTs), 52 leiomyomas, and 41 schwannomas. AI-assisted classification models for GISTs and non-GIST tumors were developed utilizing clinical and endoscopic factors and digital EUS image analysis. Results: Regarding the baseline EUS classification models, the area under the receiver operating characteristic (AUC) values of the logistic regression, decision tree, random forest, K-nearest neighbor (KNN), and support vector machine (SVM) models were 0.805, 0.673, 0.781, 0.740, and 0.791, respectively. Using the new classification models incorporating clinical and endoscopic factors into the baseline classification models, the AUC values of the logistic regression, decision tree, random forest, KNN, and SVM models increased to 0.853, 0.715, 0.896, 0.825, and 0.794, respectively. In particular, the random forest and KNN models exhibited significant improvement in performance in Delong's test (both p < 0.001). Conclusion: The diagnostic performance of the AI-assisted EUS classification models improved when clinical and endoscopic factors were incorporated. Our results provided direction for developing new AI-assisted EUS models for gastric mesenchymal tumors.

Effective Endoscopic Submucosal Dissection of a Huge Esophageal Liposarcoma: A Case Report.

This case report presents the successful endoscopic submucosal dissection (ESD) of a well-differentiated esophageal liposarcoma in a 51-year-old male with persistent dysphagia. The cause was initially diagnosed as a 10 cm pedunculated lesion extending from the upper esophageal sphincter to the mid-esophagus. An ESD was chosen over traditional surgery because it is less invasive. The procedure involved a precise submucosal injection and excision with special techniques to manage bleeding from a central vessel. Despite the extraction challenges owing to the size of the lesion, it was successfully removed orally. A histopathological examination of the 8.3×4.2×2.3 cm specimen revealed the characteristic features of a well-differentiated liposarcoma, including MDM2 and CDK4 positivity. The follow-up revealed no recurrence, and active surveillance has been performed since. This report highlights the versatility of ESD in treating significant esophageal tumors and provides evidence for its efficacy as a minimally invasive alternative.

A rare case of esophageal mucoepidermoid carcinoma successfully treated via endoscopic submucosal dissection.

Esophageal mucoepidermoid carcinoma (EMEC) is a special subtype of esophageal malignancy, accounting for less than 1% of all cases of primary esophageal carcinoma. Pathologically, it consists of a mixture of adenocarcinoma and squamous cell carcinoma with mucin-secreting cells. Special staining for mucicarmine helps to diagnose EMEC. We present a rare case of EMEC successfully treated via endoscopic submucosal dissection (ESD). A 63-year-old man was referred to our tertiary hospital. On esophagogastroduodenoscopy, a 6-mm-sized subtle reddish depressed lesion was identified in the mid-esophagus. Diagnostic ESD was performed with a high suspicion of carcinoma. Histopathologic findings were consistent with EMEC which was confined to the lamina propria without lymphatic invasion. We plan to do a careful follow-up without administering adjuvant chemotherapy or radiotherapy. Due to the small volume of the lesion, establishing a diagnosis was difficult through forceps biopsy alone. However, by using ESD, we could confirm and successfully treat a rare case of early-stage EMEC.

Comparison of Helicobacter pylori eradication rates between 7 and 14 days of tailored therapy according to clarithromycin resistance test: A randomized, multicenter, non-inferiority study.

BACKGROUND: Recently, a simple tailored therapy based on clarithromycin resistance has been implemented as Helicobacter pylori (H. pylori) eradication therapy. Nonetheless, despite the tailored therapy and frequent adverse events, studies on treatment period are lacking. This study aimed to compare the H. pylori eradication rates of 7-day and 14-day tailored therapy regimens according to clarithromycin resistance. MATERIALS AND METHODS: This multicenter, prospective, randomized, noninferiority trial enrolled H. pylori-positive patients who were randomly assigned to 7-day and 14-day regimen groups, depending on the presence or absence of clarithromycin resistance by 23S rRNA gene point mutations. Standard triple therapy (STT) (20 mg rabeprazole, 1 g amoxicillin, and 500 mg clarithromycin twice daily) or bismuth quadruple therapy (BQT) (20 mg rabeprazole twice daily, 500 mg metronidazole thrice daily, 120 mg bismuth four times daily, and 500 mg tetracycline four times daily) was assigned by clarithromycin resistance. Eradication rates and adverse events were evaluated. RESULTS: A total of 314 and 278 patients were included in the intention-to-treat (ITT) and per-protocol (PP) analyses, respectively; however, 31 patients were lost to follow-up, whereas five patients violated the protocol. Both the 7-day and 14-day regimens showed similar eradication rates in the ITT (7-day vs. 14-day: 78.3% vs. 78.3%, p > 0.99) and PP (87.9% vs. 89.1%, p = 0.851) analyses. Non-inferiority was confirmed (p < 0.025). A subgroup analysis according to clarithromycin resistance (clarithromycin resistance rate: 28.7%) revealed no significant difference in eradication rates between the 7-day and 14-day STT (90.0% vs. 90.1%, p > 0.99) and BQT (82.5% vs. 86.5%, p = 0.757). Furthermore, adverse events did not significantly differ between the two groups. CONCLUSIONS: The 7-day triple and quadruple therapy according to clarithromycin resistance showed similar eradication rates, as compared to the 14-day therapy.

A Case of Esophageal MALT Lymphoma Mimicking a Subepithelial Tumor.

Mucosa-associated lymphoid tissue (MALT) lymphoma, also known as extranodal marginal zone lymphoma, is a low-grade B-cell lymphoma that can develop in the mucosal layer of various organs, including the gastrointestinal tract, salivary glands, lungs, and skin. The most common site is the gastrointestinal tract, particularly the stomach. On the other hand, primary esophageal lymphomas are extremely rare. MALT lymphomas can undergo histological transformation into more aggressive B-cell lymphomas, such as diffuse large B-cell lymphoma, resulting in a poor prognosis. This paper reports a rare case of primary esophageal MALT lymphoma mimicking a subepithelial tumor located in the lower esophagus that was treated successfully with radiotherapy. MALT lymphoma should be included in a differential diagnosis when subepithelial tumors are found in the esophagus, particularly if endoscopic ultrasonography reveals the tumor to be located in the deep mucosal and submucosal layers. Following the precise diagnosis, accurate staging and appropriate treatment are crucial. Regular follow-up is necessary to assess the possibility of recurrence or transformation to high-grade lymphoma.

Changing trends and characteristics of peptic ulcer disease: A multicenter study from 2010 to 2019 in Korea.

BACKGROUND: The clinical trend and characteristics of peptic ulcer disease (PUD) have not fully been investigated in the past decade. AIM: To evaluate the changing trends and characteristics of PUD according to age and etiology. METHODS: We analyzed seven hospital databases converted into the Observational Medical Outcomes Partnership-Common Data Model between 2010 and 2019. We classified patients with PUD who underwent rapid urease tests or Helicobacter pylori (H. pylori) serology into three groups: H. pylori-related, drug [nonsteroidal anti-inflammatory drugs (NSAIDs) or aspirin]-related, and idiopathic (H. pylori/NSAID/aspirin-negative) PUD and compared the yearly trends and characteristics among the three groups. RESULTS: We included 26785 patients in 7 databases, and the proportion of old age (≥ 65 years) was 38.8%. The overall number of PUD exhibited no decrease, whereas PUD in old age revealed an increasing trend (P = 0.01 for trend). Of the 19601 patients, 41.8% had H. pylori-related, 36.1% had drug-related, and 22.1% had idiopathic PUD. H. pylori-related PUD exhibited a decreasing trend after 2014 (P = 0.01), drug-related PUD demonstrated an increasing trend (P = 0.04), and idiopathic PUD showed an increasing trend in the old-age group (P = 0.01) during 10 years. Patients with drug-related PUD had significantly more comorbidities and concomitant ulcerogenic drugs. The idiopathic PUD group had a significantly higher number of patients with chronic liver disease. CONCLUSION: With the aging population increase, the effects of concomitant ulcerogenic drugs and preventive strategies should be investigated in drug-induced PUD. Further studies are required to clarify the relationship between idiopathic PUD and chronic liver disease.

A Gastric Magnetic Foreign Body Incidentally Detected Several Years after Ingestion.

Foreign body ingestion is commonly seen in children. However, occasionally it may also be seen among adults and is often associated with intellectual disability, psychiatric disorders, and alcoholism. Ingestion of a magnetic foreign body may cause complications such as gastrointestinal tract perforation, wherein emergency endoscopic removal of the foreign body is generally required. Here, we report a rare case of a 59-year-old male with an intellectual disability and psychiatric disorder in whom metallic objects in the stomach cavity were accidentally discovered during abdominal CT. Esophagogastroduodenoscopy revealed several metallic objects attached to two magnets, which had been ingested several years before and had remained in the stomach cavity. The magnets and metallic objects were safely removed endoscopically using rat-tooth forceps without complications.

Long-term outcomes of endoscopic resection for duodenal neuroendocrine tumors.

Duodenal neuroendocrine tumors (d-NETs) ≤ 10 mm in size, confined to the submucosal layer, without lymph node or distant metastasis, can be treated safely and effectively by endoscopic management. However, most results are based on limited data and short follow-up outcomes. Herein, we aimed to evaluate the short-term and long-term outcomes of endoscopic resection for d-NETs. We retrospectively analyzed 63 patients with 68 d-NETs who had undergone endoscopic resection at two hospitals between January 2009 and December 2021. En-bloc resection, endoscopically complete resection, and histopathologically complete resection rates were evaluated as short-term outcomes. Furthermore, long-term outcomes were analyzed in 46 patients with 50 d-NETs with a follow-up period of > 1 year. The overall en-bloc, endoscopically complete, and histopathologically complete resection rates were 92.6% (63/68), 100% (68/68), and 69.1% (47/68), respectively. Tumor size (> 5 mm) was the only predictive factor for histopathologically incomplete resection (p = 0.015). The procedure-related bleeding and perforation rates were 0% and 5.9%, respectively. No recurrences were observed in patients with histopathologically complete resection and those with histopathologically incomplete resection at a median follow-up period of 48 months (range 12-132 months). Endoscopic resection for d-NETs ≤ 10 mm in size, limited to the submucosal layer, and without lymph node or distant metastasis provides favorable long-term outcomes when endoscopically complete resection is achieved.

Successful resolution of gastric perforation caused by a severe complication of pancreatic walled-off necrosis: A case report.

BACKGROUND: Pancreatic walled-off necrosis (WON) rarely causes critical gastric necrosis and perforation, which may develop when pancreatic WON squashes against the stomach. The Atlanta 2012 guidelines were introduced for acute pancreatitis and its related clinical entities. However, there are few reported cases describing the clinical course and resolution of pancreatic WON. CASE SUMMARY: We report the case of a 45-year-old man who presented to the urgent emergency department with gastric perforation caused by a severe complication of pancreatic WON on computed tomography. The patient underwent an emergency distal pancreatectomy, splenectomy, and gastric wedge resection. Postoperative findings showed re-perforation of the gastric wall at a previously resected margin. Furthermore, endoscopic examination revealed an ulcerative area with a defect in the fundus. After diagnostic endoscopy, endoscopic vacuum-assisted closure was performed, and continuous suction was transferred over all tissues in contact with the sponge surface. The patient recovered without any further complications and was discharged in good condition at postoperative week 8. No recurrence occurred during the 6-mo follow-up period. CONCLUSION: When managing a patient with serious gastric perforation complicated by pancreatic WON, a multidisciplinary treatment approach should be considered.

Identification of miR-143-3p as a diagnostic biomarker in gastric cancer.

BACKGROUND: Gastric cancer (GC) is among the most common types of gastrointestinal cancers and has a high incidence and mortality around the world. To suppress the progression of GC, it is essential to develop diagnostic markers. MicroRNAs regulate GC development, but a clearer insight into their role is needed before they can be applied as a molecular markers and targets. METHODS: In this study, we assessed the diagnostic value of differentially expressed microRNAs as potential diagnostic biomarkers for GC using data for 389 tissue samples from the Cancer Genome Atlas (TCGA) and 21 plasma samples from GC patients. RESULTS: The expression of hsa-miR-143-3p (also known as hsa-miR-143) was significantly downregulated in GC according to the TCGA data and plasma samples. The 228 potential target genes of hsa-miR-143-3p were analyzed using a bioinformatics tool for miRNA target prediction. The target genes correlated with extracellular matrix organization, the cytoplasm, and identical protein binding. Furthermore, the pathway enrichment analysis of target genes showed that they were involved in pathways in cancer, the phosphoinositide 3-kinase (PI3K)-protein kinase B (Akt) signaling pathway, and proteoglycans in cancer. The hub genes in the protein-protein interaction (PPI) network, were matrix metallopeptidase 2 (MMP2), CD44 molecule (CD44), and SMAD family member 3 (SMAD3). CONCLUSIONS: This study suggests that hsa-miR-143-3p may be used as a diagnostic marker for GC, contributing via the pathways involved in the development of GC.

Feasibility of endoscopic resection and impact of endoscopic ultrasound-based surveillance on colorectal subepithelial tumors.

BACKGROUND: Owing to the rising number of screening endoscopies and instrumental advances in endoscopic ultrasound (EUS), colorectal subepithelial tumors (SETs) are being increasingly detected. We aimed to determine the feasibility of endoscopic resection (ER) and the impact of EUS-based surveillance on colorectal SETs. METHODS: The medical records of 984 patients with incidentally detected colorectal SETs between 2010 and 2019 were retrospectively reviewed. Overall, 577 colorectal SETs underwent ER, and 71 colorectal SETs underwent serial colonoscopy for > 12 months. RESULTS: The mean tumor size (± standard deviation) of 577 colorectal SETs for which ER was performed was 7.0 ± 5.7 (median, 55; range, 1-50) mm; 475 tumors were located in the rectum and 102, in the colon. En bloc resection was achieved in 560/577 treated lesions (97.1%), and complete resection was achieved in 516/577 (89.4%). ER-related adverse events occurred in 15/577 (2.6%) patients. SETs originating from the muscularis propria showed a higher risk of ER-related adverse events and perforation than SETs arising from the mucosal or submucosal layer (odds ratio [OR] 19.786, 95% confidence interval [CI] 4.556-85.919; P = 0.002 and OR 141.250, 95% CI 11.596-1720.492; P = 0.046, respectively). Seventy-one patients were followed up after EUS without any treatment for > 12 months, during which three showed progression; eight, regression; and sixty, no changes. CONCLUSIONS: ER for colorectal SETs showed excellent efficacy and safety. Additionally, colorectal SETs without high-risk features in surveillance with colonoscopy showed an excellent prognosis.

Endoscopic Resection for Gastric Adenocarcinoma of the Fundic Gland Type: A Case Series.

The fundic gland type (GA-FG) of gastric adenocarcinoma is a rare variant of gastric cancer recently included in the 5th edition of the World Health Organization's classification of digestive system tumors. Five patients with GA-FG underwent an endoscopic resection at our institution. None of the patients had a Helicobacter pylori infection. Four lesions were located in the upper third of the stomach, and one was in the lower third. Three lesions had a IIa shape, while two resembled a subepithelial tumor. An endoscopic submucosal dissection was performed in four patients and endoscopic mucosal resection in one. Tumor cells were composed of well-differentiated columnar cells mimicking fundic gland cells, and the median tumor size was 10 mm. Three lesions exhibited submucosal invasion. No lymphatic or venous invasion was observed. Tumor cells were positive for MUC6 in all five cases; one case was focally positive for MUC5AC. No recurrence was observed during a median follow-up period of 13 months. An endoscopic resection can be a safe treatment modality for GA-FG, considering its small size and low risk of recurrence or metastasis.

Incidence and adverse clinical events of primary sclerosing cholangitis with ulcerative colitis.

PURPOSE: The aim of this study was to conduct a nationwide population-based study to estimate the incidence of primary sclerosing cholangitis in patients with ulcerative colitis (UC-PSC) and investigate healthcare use, medication use, surgery, cancer, and death as adverse clinical events of UC-PSC. METHODS: We identified incident cases of UC with (UC-PSC) or without PSC (UC-alone) between 2008 and 2018 using health insurance claims data in Korea. Univariate (crude hazard ratio (HR)) and multivariate analyses were performed to compare the risk of adverse clinical events between groups. RESULTS: A total of 14,406 patients with UC using population-based claims data were detected in the cohort. Overall, 3.38% (487/14,406) of patients developed UC-PSC. During a mean follow-up duration of approximately 5.92 years, the incidence of PSC in patients with UC was 185 per 100,000 person-years. The UC-PSC group showed statistically more frequent healthcare use (hospitalization and emergency department visits: HRs, 5.986 and 9.302, respectively; P < .001), higher immunomodulator and biologic use (azathioprine, infliximab, and adalimumab: HRs, 2.061, 3.457, and 3.170, respectively; P < .001), and higher surgery rate (operation for intestinal obstruction, and colectomy: HRs, 9.728 and 2.940, respectively; P < .001) than did the UC-alone group. The UC-PSC group also showed significantly higher colorectal cancer and biliary tract cancer (HRs, 2.799 and 36.343, respectively; P < .001) and mortality (HR, 4.257) rates than did the UC-alone group. CONCLUSION: Patients with UC-PSC have higher risks of colorectal cancer, biliary tract cancer, and death than do patients with UC-alone. Although considered a rare disease, managing this complex and costly disease requires recognition of the impact of increased burden on healthcare services.

Magnifying Endoscopy with Narrow-Band Imaging for Duodenal Neuroendocrine Tumors.

Duodenal neuroendocrine tumors (NETs) are rare subepithelial tumors that arise from the neuroendocrine cells beneath the epithelial layer. However, an accurate histopathological diagnosis is difficult when tissue samples are obtained using conventional endoscopic forceps biopsy alone. This study aimed to evaluate the magnifying endoscopy with narrow-band imaging (ME-NBI) findings of duodenal NETs. We retrospectively analyzed a database of 22 duodenal NETs from 21 patients who underwent ME-NBI between January 2011 and June 2022. The ME-NBI, endosonographic, and histopathologic findings of duodenal NETs were analyzed. Nineteen lesions were located in the bulb, two were located in the superior duodenal angle, and one was located in the second portion of the duodenum. Eighteen lesions (82%) had IIa morphology, and nine (41%) had central depression on the surface. On endoscopic ultrasonography, almost all lesions (20/22, 91%) were located in the second and/or third layers, and the median tumor size was 6 mm. During ME-NBI, the microsurface pattern was regular in 18 lesions (82%) and absent in 4 (18%). The microvascular pattern was regular in 17 lesions (77%), irregular in 4 (18%), and absent in 1 (5%). Thickened subepithelial vessels were observed in 15 (68%) lesions. There was no difference in tumor size according to the presence or absence of thickened subepithelial vessels (6.1 ± 1.8 mm vs. 5.9 ± 3.8 mm, p = 0.860). In conclusion, the characteristic ME-NBI findings of duodenal NETs were regular microsurface and microvascular patterns and the presence of thickened subepithelial vessels. These ME-NBI features may be useful for differentiating duodenal NETs from other duodenal subepithelial lesions.

A randomized controlled trial to compare Helicobacter pylori eradication rates between the empirical concomitant therapy and tailored therapy based on 23S rRNA point mutations.

BACKGROUND: Increasing clarithromycin resistance has led to changes in several guidelines for treatment of Helicobacter pylori infections. We compared the H. pylori eradication rates of the empirical concomitant therapy (CoT) and a tailored therapy (TaT) using dual-priming oligonucleotide-based polymerase chain reaction to detect mutations in the 23S rRNA gene that are related to clarithromycin resistance. METHODS: Between June 2020 and May 2021, 290 patients were enrolled and randomly assigned to 2 groups. In the CoT group, the patients received rabeprazole 20 mg, amoxicillin 1 g, clarithromycin 500 mg, and metronidazole 500 mg twice daily for 14 days. In the TaT group, point mutation-negative patients received rabeprazole 20 mg, amoxicillin 1 g, and clarithromycin 500 mg twice daily for 14 days and point mutation-positive patients received rabeprazole 20 mg twice daily, metronidazole 500 mg thrice daily, and bismuth 120 mg and tetracycline 500 mg 4 times daily for 14 days. RESULTS: A total of 290 and 261 patients were included in the intention-to-treat (ITT) and per-protocol (PP) analyses, respectively. A2142G and/or A2143G point mutations were identified in 28.6% of the patients. No significant difference in eradication rates were observed between the 2 groups as per ITT (CoT, 82.8% and TaT, 85.5%, P = .520) and PP (CoT, 88.6% and TaT, 94.6%, P = .084) analyses. In point mutation-positive patients, the eradication rates in the CoT group were lower than those in the TaT group as per ITT (69.8% and 87.5%, respectively, P = .050) and PP (76.9% and 97.1%, respectively, P = .011) analyses. CONCLUSION: CoT and TaT showed similar overall eradication rates for H. pylori. However, CoT eradication rate was suboptimal, especially in point mutation-positive patients.

Exosomal MicroRNA Analyses in Esophageal Squamous Cell Carcinoma Cell Lines.

Exosomal miRNAs have been studied in various cancers as minimally invasive biomarkers. This study aimed to investigate the potential of exosomal microRNAs (miRNAs) as biomarkers for esophageal squamous cell carcinoma (ESCC). Exosomes were isolated from cultures of esophageal epithelial cell and ESCC cell lines using ExoDisc, and exosomal miRNAs were detected via miRNA sequencing. Of the differentially expressed 14 miRNAs, the top 2 up-regulated miRNAs (miR-205-5p and miR-429) and top 2 down-regulated miRNAs (miR-375-3p and miR-483-3p) were selected as ESCC target miRNAs. Four selected exosomal miRNAs were validated in the plasma of 20 healthy controls (HCs) and 40 ESCC patients via quantitative reverse transcription-polymerase chain reaction. The expression of plasma exosomal miR-205-5p and miR-429 significantly increased, while that of plasma exosomal miR-375-3p was significantly reduced in ESCC patients compared to that in HCs. At cut-off values of 5.04, 2.564, and 0.136, the sensitivity and specificity for the diagnosis of ESCC were 72.5% and 70.0% for miR-205-5p, 60.0% and 60.0% for miR-429, and 65.0% and 65.0% for miR-375-3p, respectively. Based on the exosomal miRNAs identified in ESCC cell lines, our study demonstrated that plasma exosomal miR-205-5p, miR-429, and miR-375-3p could serve as potential biomarkers for ESCC diagnosis.

MicroRNA Expression in Plasma of Esophageal Squamous Cell Carcinoma Patients.

BACKGROUND: Patients with esophageal squamous cell carcinoma (ESCC) have a poor prognosis and there are no effective clinical biomarkers. Recently, stable microRNAs detected in the blood have been suggested as potential biomarkers in various cancers. Therefore, we investigated whether plasma microRNAs could be feasible biomarkers for ESCC. METHODS: Peripheral blood samples were obtained from 16 healthy volunteers and 66 ESCC patients before treatment between May 2016 and April 2021. Plasma miR-18b, miR-21, miR-31, and miR-375 expression levels were measured using reverse transcription-quantitative polymerase chain reaction. RESULTS: Compared with those in healthy controls, the expression levels of plasma miR-21 were significantly higher (P = 0.022) and those of plasma miR-31 and miR-375 were significantly lower in ESCC patients (both P < 0.001). Plasma miR-18b expression levels increased in ESCC patients, but the difference was not significant (P = 0.164). The sensitivities and specificities of miR-21, miR-31, and miR-375 for differentiating ESCC patients from healthy controls were 87.5% and 61.9%, 87.5% and 98.4%, and 87.5% and 100%, respectively. There was no difference in expression levels of plasma miR-21, miR-31, and miR-375 according to clinicopathological characteristics of sex, age, tumor size and location, histologic grade, and tumor-node-metastasis stage. CONCLUSION: Our study demonstrated that plasma miR-21, miR-31, and miR-375 could be potential biomarkers for the diagnosis of ESCC. Particularly, plasma miR-31 and miR-375 showed high sensitivity and specificity for differentiating ESCC patients from healthy controls.

Diagnostic performance of endoscopic ultrasonography-guided fine-needle biopsy in upper gastrointestinal subepithelial tumors measuring 2-5 cm in size.

BACKGROUND: Subepithelial tumors (SETs) in the upper gastrointestinal (GI) tract are frequently discovered during upper endoscopy, and their management is determined based on size and histopathological diagnosis. We aimed to evaluate the diagnostic performance of endoscopic ultrasonography-guided fine-needle biopsy (EUS-FNB) in upper GI SETs of 2-5 cm in size. METHODS: We included 63 patients who underwent EUS-FNB for upper GI SETs of 2-5 cm in size between January 2013 and February 2020. The diagnostic yield of EUS-FNB, ability of EUS-FNB in discriminating malignant from non-malignant lesions, and histopathological concordance between EUS-FNB specimens and resected specimens were evaluated. RESULTS: Successful acquisition of macroscopic tissue cores was possible in all 63 cases, and the diagnostic yield of EUS-FNB was 92.1% (58/63). The sensitivity, specificity, and accuracy of EUS-FNB in discriminating malignant from non-malignant lesions were 100% (95% confidence interval [CI] 85.3-100%), 87.8% (95% CI 79.9-87.8%), and 92.1% (95% CI 81.8-92.1%), respectively. Of the 26 SETs that were endoscopically or surgically resected after EUS-FNB, the histopathological concordance rate between the EUS-FNB specimens and resected specimens was 100% (24/24), except in two cases of inadequate results with EUS-FNB specimens. CONCLUSION: EUS-FNB provides high diagnostic yield and high capability in discriminating malignant from non-malignant lesions in upper GI SETs of 2-5 cm in size.