Clinical course of gastrointestinal stromal tumor diagnosed by endoscopic ultrasound-guided fine-needle aspiration

Feasibility of Endoscopic Ultrasound-Guided Tissue Acquisition for < 20-mm Upper Gastrointestinal Subepithelial Lesions

BACKGROUND

There are few reports on the usefulness of endoscopic ultrasound-guided tissue acquisition (EUS-TA) for upper gastrointestinal subepithelial lesions (SELs) < 20 mm with on-site stereomicroscopic assessment.

AIM

This study is aimed at investigating the usefulness of EUS-TA combined with on-site stereomicroscopic assessment using fine-needle biopsy (FNB) for SELs < 20 mm.

METHODS

Participants (n = 133) underwent EUS-TA combined with on-site stereomicroscopic assessment using a 22-gauge FNB needle for upper gastrointestinal SELs between January 2018 and January 2022. We conducted a comparative study of diagnostic results after dividing the participants into two groups on the basis of lesion size: < 20 and ≥ 20 mm.

RESULTS

There were 42 cases in the < 20-mm group and 91 cases in the ≥ 20-mm group. The diagnostic yield of EUS-TA in all cases was 97.7%, with values of 97.6% in the < 20-mm group and 97.8% in the ≥ 20-mm group and no significant difference between the groups. A total of 298 passes were made. The tissue sampling rate was 99.0%, and specimens with stereomicroscopically visible white cores (SVWCs) ≥ 4 mm were sampled at a rate of 87.2%. There was no significant difference in the sampling rate of specimens with SVWCs ≥ 4 mm between the groups. The diagnostic sensitivity in specimens with SVWC ≥ 4 mm was 98.5% (256/260 passes). Multivariate analysis showed that this factor significantly contributed to diagnosis (odds ratio 24.396, 95% confidence interval: 1.6596-4.7292, p < 0.001).

CONCLUSIONS

EUS-TA using a FNB needle combined with on-site stereomicroscopic assessment is a useful diagnostic method for < 20-mm SELs.

The value of a nomogram model based on CT imaging features in differentiating duodenal gastrointestinal stromal tumors from pancreatic head neuroendocrine tumors

OBJECTIVE

To construct a nomogram model based on multi-slice spiral CT imaging features to predict and differentiate between duodenal gastrointestinal stromal tumors (GISTs) and pancreatic head neuroendocrine tumors (NENs), providing imaging evidence for clinical treatment decisions.

METHODS

A retrospective collection of clinical information, pathological results, and imaging data was conducted on 115 cases of duodenal GISTs and 76 cases of pancreatic head NENs confirmed by surgical pathology at Zhongshan Hospital Fudan University from November 2013 to November 2022. Comparative analysis was performed on the tumor's maximum diameter, shortest diameter, long diameter/short diameter ratio, tumor morphology, tumor border, central position of the lesion, lesion long-axis direction, the relationship between tumor and common bile duct (CBD), duodenal side ulceration of the lesion, calcification, cystic and solid proportion within the tumor, thickened feeding arteries, tumor neovascularization, distant metastasis, and CT values during plain and enhanced scans in arterial and venous phases. Statistical analysis was conducted using t-tests, Mann-Whitney U tests, and χ2 tests. Univariate and multivariate logistic regression analyses were used to identify independent predictors for differentiating duodenal GISTs from pancreatic head NENs. Based on these independent predictors, a nomogram model was constructed, and the receiver operating characteristic (ROC) curve was used to evaluate the diagnostic performance of the model. The nomogram was validated using a calibration curve, and decision curve analysis was applied to assess the clinical application value of the nomogram.

RESULTS

There were significant differences in the duodenal GISTs group and the pancreatic head NENs group in terms of longest diameter (P < 0.001), shortest diameter (P < 0.001), plain CT value (P < 0.001), arterial phase CT value (P < 0.001), venous phase CT value (P = 0.002), lesion long-axis direction (P < 0.001), central position of the lesion (P < 0.001), the relationship between tumor and CBD(< 0.001), border (P = 0.004), calcification (P = 0.017), and distant metastasis (P = 0.018). Multivariate logistic regression analysis identified uncertain location (OR 0.040, 95% CI 0.003-0.549), near the duodenum (OR 0, 95% CI 0-0.009), with the lesion long-axis direction along the pancreas as a reference, along the duodenum (OR 0.106, 95% CI 0.010-1.156) or no significant difference (OR 4.946, 95% CI 0.453-54.017), and the relationship between tumor and CBD (OR 0.013, 95% CI 0.001-0.180), shortest diameter (OR 0.705, 95% CI 0.546-0.909), and calcification (OR 18.638, 95% CI 1.316-263.878) as independent risk factors for differentiating between duodenal GISTs and pancreatic head NENs (all P values < 0.05). The combined diagnostic model's AUC values based on central position of the lesion, calcification, lesion long axis orientation, the relationship between tumor and CBD, shortest diameter, and the joint diagnostic model were 0.937 (0.902-0.972), 0.700(0.624-0.776), 0.717(0.631-0.802), 0.559 (0.473-0.644), 0.680 (0.603-0.758), and 0.991(0.982-0.999), respectively, with a sensitivity of 97.3% and a specificity of 93.0% for the joint diagnostic model. The nomogram model's AUC value was 0.985(0.973-0.996), with a sensitivity and specificity of 94.7% and 93.9%, respectively. The calibration curve indicated good agreement between predicted and actual risks. Decision curve analysis verified the clinical application value of the nomogram.

CONCLUSION

The nomogram model based on CT imaging features effectively differentiates between duodenal GISTs and pancreatic head NENs, aiding in more precise clinical treatment decisions.

Common Symptoms and a Rare Diagnosis: A Case of Duodenal Gastrointestinal Stromal Tumor Presenting as Gastrointestinal Bleeding

Duodenal gastrointestinal stromal tumors (D-GISTs) are a rare subtype of GISTs, accounting for only 4% to 5% of all GIST cases. This case report details the presentation, diagnosis, and management of a 48-year-old female who presented with melena and anemia and was eventually diagnosed with a D-GIST. The tumor was identified through imaging studies, and histopathology performed after surgical resection revealed a submucosal neoplasm composed of spindle cells with extensive hemorrhage and necrosis. Given the tumor's rarity and its challenging presentation, which can mimic other conditions such as pancreatic masses, the case underscores the importance of considering D-GIST in differential diagnoses of duodenal or pancreatic lesions. Surgical resection remains the cornerstone of treatment, with adjuvant therapy considered in high-risk cases to prevent recurrence.

Clinical course of small gastric subepithelial lesion less than 20 mm diagnosed by endoscopic ultrasound-guided fine-needle aspiration

BACKGROUND AND AIM

Gastrointestinal stromal tumors (GISTs) are treated as malignant gastric subepithelial lesions (SELs), and resection is recommended. However, small gastric SELs < 20 mm with no malignant features are monitored without histopathological examination, and the frequency of malignancy is unknown. This study aimed to clarify the clinicopathological findings and clinical course of gastric SELs < 20 mm measured by endoscopic ultrasound (EUS).

METHODS

This retrospective cohort study included consecutive patients with small gastric SELs < 20 mm diagnosed using EUS at a tertiary referral center between 2009 and 2021. The clinical course after diagnosis using EUS-guided fine-needle aspiration (EUS-FNA) was reviewed.

RESULTS

Among 333 patients with small gastric SELs, 104 patients with 105 lesions underwent EUS-FNA. The pathological diagnosis was confirmed in 87 patients. GISTs were the most common pathology (47%). Among the 87 patients, 43 underwent therapeutic interventions, including tumor resection and chemotherapy. In groups of tumor resection, the pathological tumor size on the resected specimen was significantly larger than the size measured by EUS (19.5 mm vs 15.0 mm, P < 0.001), and 37% of resected SELs were 20 mm or over. No recurrence was observed after tumor resection during a mean follow-up period of 40 months.

CONCLUSIONS

Approximately 40% of small gastric SELs were malignant tumors, such as GIST, with most of them requiring treatment. Additionally, considering that the EUS measurement is 5 mm smaller than the pathological tumor diameter, further examinations, such as systematic EUS-FNA, may be required for SEL, including those smaller than 20 mm.

Diagnostic yield of endoscopic and EUS-guided biopsy techniques in subepithelial lesions of the upper GI tract: a systematic review

BACKGROUND AND AIMS

Obtaining adequate tissue samples in subepithelial lesions (SELs) remains challenging. Several biopsy techniques are available, but a systematic review including all available techniques to obtain a histologic diagnosis of SEL is lacking. The aim of this study was to evaluate the diagnostic yield and adverse event rates of endoscopic biopsies, EUS-guided FNA (EUS-FNA), EUS-guided fine-needle biopsy (FNB) (EUS-FNB), and mucosal incision-assisted biopsy (MIAB) for SELs in the upper GI tract.

METHODS

A search strategy in multiple databases was performed. The primary outcome was diagnostic yield, defined as the percentage of procedures in which histology was obtained and resulted in a definitive histopathologic diagnosis. Secondary outcome measures included reported procedure-related adverse events, which were graded according to the AGREE (Adverse Events in Gastrointestinal Endoscopy) classification.

RESULTS

A total of 94 original articles were included. Studies were classified per endoscopic technique to obtain histopathology. This resulted in 8 included studies for endoscopic biopsy methods, 55 studies for EUS-FNA, 33 studies for EUS-FNB, and 26 studies for MIAB. Pooled rates for diagnostic yield were 40.6% (95% confidence interval [CI], 30.8-51.2) for endoscopic biopsy, 74.6% (95% CI, 69.9-78.7) for EUS-FNA, 84.2% (95% CI, 80.7-87.2) for EUS-FNB, and 88.2% (95% CI, 84.7-91.1) for MIAB. Reported procedure-related adverse events graded AGREE II or higher were 2.8% to 3.9% for endoscopic biopsies, 1.0% to 4.5% for EUS-FNA, .9% to 7.7% for EUS-FNB, and 1.9% to 7.9% for MIAB.

CONCLUSIONS

Based on the available evidence, MIAB and EUS-FNB seem to be most effective in terms of achieving a high diagnostic yield, with similar rates of adverse events.

Endoscopic ultrasound-guided fine-needle aspiration for gastrointestinal subepithelial lesions

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is the first-choice procedure for obtaining pathological tissue samples from gastrointestinal (GI) subepithelial lesions (SELs). However, its diagnostic accuracy is lower than that for pancreatic masses owing to puncture difficulty and the need for immunostaining for definitive diagnosis. The advent of fine-needle biopsy needles, which have become well known in recent years, improves the diagnostic accuracy of EUS-FNA for GI SELs. The forward-viewing echoendoscope and rapid on-site evaluation (ROSE) have also helped to improve diagnostic accuracy. Furthermore, in facilities where ROSE is not available, endosonographers perform a macroscopic on-site evaluation. With these procedural innovations, EUS-FNA is now performed aggressively even for SELs smaller than 20 mm. The incidence of procedure-related adverse events such as bleeding and infection is low, and thus, EUS-FNA can be safely performed to diagnose SELs.

Gastrointestinal Stromal Tumors and the General Surgeon

Gastrointestinal stromal tumors (GISTs) are rare malignancies of the gastrointestinal tract but are the most common sarcoma. This review covers aspects of the care of patients with GIST relevant to surgeons. In particular, management of sub-2 cm GISTs, the utility of neoadjuvant and adjuvant therapy for primary GISTs, and indications for surgery in the setting of metastatic disease are discussed.

Endoscopic Ultrasonography-guided Fine-needle Aspiration Cytology Combined with a Cell-block Method for Gastrointestinal Subepithelial Lesions

Objective The diagnostic accuracy of an endoscopic ultrasound-guided fine-needle aspiration cytology/biopsy combined with a cell-block method (FNA-CB) for gastrointestinal subepithelial lesions (GI-SELs) has not been fully studied. Methods A total of 109 patients (with 110 GI-SELs) were evaluated to clarify the rate of obtaining evaluable histology specimens using FNA-CB. In addition, we investigated the following: 1) the accuracy for determining the histology, 2) effects of the number of cell clusters obtained via FNA-CB, 3) correlation of the Ki67 labelling index (Ki67LI) of the gastrointestinal stromal tumor (GIST) lesions between FNA-CB and resected specimens, and 4) clinical courses for patients followed up after FNA-CB. Results Of the 110 GI-SELs for which FNA-CB was performed, 95 (86%) were able to be histologically evaluated using the first FNA-CB. For the 70 resected GI-SELs, the accuracy of FNA-CB to determine histology was 96%, remaining at 90% even when only a few cell clusters were obtained. The concordance rate of the risk-grouping of GIST (high-risk, Ki67LI ≥8; low-risk, <8) between FNA-CB and resected specimens was 84%. Of the 29 patients followed up after the first FNA-CB, 12 with benign GI-SELs determined using the first FNA-CB showed no obvious increases in their GI-SEL sizes. Conclusion Since FNA-CB can be used to determine the histology and reproductive activity of GI-SELs accurately, not only preoperative histological confirmation but also reliable information to determine clinical plans, such as follow-up without surgery or neoadjuvant chemotherapy, can be obtained.

The Diagnosis of Small Gastrointestinal Subepithelial Lesions by Endoscopic Ultrasound-Guided Fine Needle Aspiration and Biopsy

Endoscopic ultrasonography (EUS) has been widely accepted in the diagnosis of all types of tumors, especially pancreatic tumors, lymph nodes, and subepithelial lesions (SELs). One reason is that the examination can provide a detailed observation, with tissue samples being immediately obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). Many SELs are detected incidentally during endoscopic examinations without symptoms. Most SELs are mesenchymal tumors originating from the fourth layer, such as gastrointestinal stromal tumors (GISTs), leiomyomas, and schwannomas. GISTs are potentially malignant. Surgical treatment is recommended for localized GISTs of ≥20 mm. However, the indications for the diagnosis and follow-up of GISTs of <20 mm in size are controversial. There are several reports on the rapid progression or metastasis of small GISTs. Therefore, it is important to determine whether a SEL is a GIST or not. The main diagnostic method is EUS-FNA. Recently, endoscopic ultrasound-guided fine needle biopsy (EUS-FNB) using a new biopsy needle has been reported to obtain larger tissue samples. Additionally, various biopsy methods have been reported to have a high diagnostic rate for small GISTs. In local gastric SELs, regardless of the tumor size, EUS can be performed first; then, EUS-FNA/B or various biopsy methods can be used to obtain tissue samples for decision-making in relation to therapy and the follow-up period.

Utility of endoscopic ultrasonography-guided fine-needle biopsy (EUS-FNB) for diagnosing small subepithelial lesions (< 20 mm)

AIM

Subepithelial lesions (SELs) are defined as being located under the mucosa. Presently, endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is commonly performed to diagnose SELs. With the development of new puncture needles, endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB), which allows for the acquisition of large tissue samples, has been proposed. However, studies on EUS-FNB of SELs measuring < 20 mm have not yielded satisfactory results. Therefore, we aimed to assess the performance and usefulness of EUS-FNB of SELs measuring less than < 20 mm.

METHODS

The present study included 62 patients who underwent EUS-FNA or EUS-FNB for SELs at our hospital between January 2015 and March 2019. EUS-FNA was performed using fine-needle aspiration needles, and EUS-FNB was performed using fine-needle biopsy needles. These needles, which come in different shapes and diameters, were compared in terms of their usefulness in performing procedures for SELs measuring ≥ 20 mm and those measuring < 20 mm.

RESULTS

For SELs measuring ≥ 20 mm, the use of needles with a large diameter, such as 19 or 20 G, resulted in significantly improved diagnostic rates. For SELs measuring < 20 mm, the use of FNB needles showed significantly improved diagnostic rates, regardless of the size of the puncture needles.

CONCLUSION

Even when SELs are less than 20 mm, they might have malignant potential, and histological diagnosis may be desirable in some cases. EUS-FNB has an advantage over EUS-FNA in the diagnosis of SELs measuring < 20 mm.

A liver metastasis 7 years after resection of a low-risk duodenal gastrointestinal stromal tumor

Duodenal gastrointestinal stromal tumors (dGISTs) are rare, and a lack of consensus exists regarding their treatment, particularly for recurrent disease. We herein report a rare case of liver metastasis 7 years after resection of a low-risk duodenal gastrointestinal stromal tumor. A 45-year-old woman revealed positive fecal occult blood. Upper gastrointestinal endoscopy revealed a submucosal duodenal tumor with ulceration and oozing on the apex. Endoscopic ultrasound showed a hypoechoic mass originating in the submucosa. Contrast-enhanced abdominal computed tomography (CT) revealed a 30-mm hyper-vascular tumor in the duodenal bulb. The patient underwent partial resection of the duodenal bulb with distal gastrectomy, followed by Roux-en-Y reconstruction. Histopathological evaluation revealed a tumor comprised of spindle-shaped cells including 5 mitotic figures per 50 high-power fields. Immunohistochemical evaluation indicated that the tumor cells were positive for c-Kit and CD34 expression. The tumor was diagnosed as low-risk dGIST. Postoperative follow-up was continued, and 7 years later, CT revealed a 39-mm enhanced tumor in liver segment 4. The tumor was diagnosed as a metastatic liver tumor, and the patient underwent S4 partial hepatectomy. As a result of histological and immunohistochemical analysis, the tumor was diagnosed as a liver metastasis from dGIST. The patient has been receiving oral imatinib 400 mg daily and remains free of disease 5 years after her last surgery. Low-risk dGIST can metastasize relatively long after surgery. However, an excellent long-term prognosis may be achieved by combining complete resection and imatinib therapy in patients with recurrent liver metastases.

Diagnosis and Treatment of Duodenal Gastrointestinal Stromal Tumors

The diagnostic value of different noninvasive diagnostic modalities and the endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) reliability of duodenal gastrointestinal stromal tumors (GISTs) are ambiguous in the present studies.

Indocyanine green-labeled dasatinib as a new fluorescent probe for molecular imaging of gastrointestinal stromal tumors

BACKGROUND AND AIM

It is difficult to differentiate gastrointestinal stromal tumors (GISTs) from other subepithelial lesions under gastrointestinal endoscopy. Because most GISTs express tyrosine kinase receptor c-KIT, fluorescence-labeled c-KIT-specific tyrosine kinase inhibitors seem to be useful agents for molecular imaging of GIST. We aimed to develop a near-infrared fluorescent imaging technology for GIST targeting c-KIT using the novel fluorescent probe indocyanine green-labeled dasatinib (ICG-dasatinib) and to investigate the antitumor effect of ICG-dasatinib on GIST cells.

METHODS

Indocyanine green-labeled dasatinib was synthesized by labeling linker-induced dasatinib with ICG derivative 3-indocyanine-green-acyl-1,3-thiazolidine-2-thione. Human GIST cell lines GIST-T1 and GIST-882M were incubated with ICG-dasatinib and observed by fluorescent microscopy. GIST cells were incubated with ICG-dasatinib, unlabeled dasatinib, or imatinib, and cell viabilities were evaluated. Subcutaneous GIST model mice or orthotopic GIST model rats were intravenously injected with ICG-dasatinib and observed using an IVIS Spectrum.

RESULTS

Strong fluorescent signals of ICG-dasatinib were observed in both GIST cell lines in vitro. IC50 values for ICG-dasatinib, unlabeled dasatinib, and imatinib were 13.9, 1.17, and 16.2 nM in GIST-T1 and 26.6, 3.63, and 47.6 nM in GIST-882M cells, respectively. ICG-dasatinib accumulated in subcutaneous xenografts in mice. Fluorescent signals were also observed in liver and gallbladder, indicating biliary excretion; however, fluorescence intensity of tumors was significantly higher than that of intestine after washing. Strong fluorescent signals were observed in orthotopic xenografts through the covering normal mucosa in rats.

CONCLUSIONS

Indocyanine green-labeled dasatinib could visualize GIST cells and xenografted tumors. The antitumor effect of ICG-dasatinib was preserved to the same degree as imatinib.

Optimal Endoscopic Resection Technique for Selected Gastric GISTs. The Endoscopic Suturing System Combined with ESD-a New Alternative?

Background and Study Aim: In terms of therapeutic management, gastrointestinal stromal tumors (GISTs) seem to be the most difficult group of subepithelial gastrointestinal lesions (SELs). Despite various treatment option, choice of optimal management remains a dilemma in daily practice. Our aim was to evaluate a new hybrid resection technique of gastric GISTs type III as a modality of endoscopic full-thickness resection. Methods: Three males and one female (mean age of 68) were qualified for the procedure. Endoscopic full-thickness resections consisted of the endoscopic resection combined with suturing by Apollo OverStitch System. The main inclusion criterium was a complete diagnosis of GISTs (computed tomography (CT), endoscopic ultrasound (EUS), fine-needle biopsy (FNB)) with the evaluation of the tumor features, especially, the location in the gastric wall. All of the tumors were type III with a diameter between 20–40 mm. The lesions were located in the corpus (1), antrum (1) and between gastric body and fundus (2). All procedures were performed in 2019. Results: The technical and therapeutic success rate was 100% and the mean resection time 107.5 min. Neither intra- nor postprocedural complications were observed. In all four cases, R0 resection was achieved. Histopathologic assessment confirmed GIST with <5mitose/50HPF in all of the tumors, with very low risk. Conclusion: Based on our outcomes, endoscopic resection combined with the sewing by Apollo OverStitch of gastric GISTs type III, with the diameter between 20–40 mm, seems to be an effective therapeutic option with a good safety profile, however further studies with a larger treatment group are needed.

Gastrointestinal Stromal Tumors of the Small Intestine: Progress in Diagnosis and Treatment Research

In recent years, the diagnosis and treatment of gastrointestinal stromal tumors (GISTs) of the small intestine have been a hot topic due to their rarity and non-specific clinical manifestations. With the development of gene and imaging technology, surgery, and molecular targeted drugs, the diagnosis and treatment of GISTs have achieved great success. For a long time, radical resection was prioritized to treat GISTs of the small intestine. At present, preoperative tumor staging is a novel treatment for unresectable malignant tumors. In addition, karyokinesis exponent is the sole independent predictor of progression-free survival of GISTs. The DNA, miRNA, and protein of exosomes have also been found to be biomarkers with prognostic implications. The research on the treatment of GISTs has become a focus in the era of precision medicine, ushering in the use of standardized, normalized, and individualized treatment.

Comparison of the treatment outcomes of endoscopic and surgical resection of GI stromal tumors in the stomach: a propensity score-matched case-control study

BACKGROUND AND AIMS

We aimed to investigate the safety and efficacy of endoscopic resection (ER) compared with surgical resection (SR) of gastric GI stromal tumors (GISTs).

METHODS

This study included 51 and 403 patients who underwent ER and SR, respectively, for ≤5 cm GISTs in the stomach between June 2005 and August 2017. After propensity score matching (1:1) using age, sex, tumor size, mitotic count, and comorbidities, the oncologic outcomes were compared with 48 patients each from ER and SR groups.

RESULTS

The ER group had significantly shorter hospital stay (4.4 ± 2.9 vs 6.6 ± 3.6 days, P < .001) and procedure time (38.3 ± 24.2 vs 66 ± 33.3 min, P < .001). The R0 resection rate was 62.7% in the ER group and 98.5% in the SR group. In the ER group, macroperforation occurred in 6 patients (11.8%) with a tumor located in the fundus (4/6, 66.7%) or body (2/6, 33.3%). All cases of perforation were cured with conservative treatment. In the SR group, postoperative adverse events such as stricture and leakage occurred in 7 patients (1.7%) with a tumor located in the antrum (4/7, 57.1%) or cardia (3/7, 42.9%). After matching, the overall mean follow-up period was 47.9 ± 37.8 months in the ER group and 41.3 ± 22.6 months in the SR group. No recurrence or distant metastasis occurred in either group during the follow-up period.

CONCLUSIONS

ER is an effective and safe therapeutic method that might be comparable with SR for treating small-sized (≤5 cm) gastric GISTs. Selecting the resection method according to the tumor location seems appropriate.

On-site stereomicroscope quality evaluations to estimate white core cutoff lengths using EUS-FNA biopsy sampling with 22-gauge needles

BACKGROUND AND AIMS

Although rapid on-site cytologic evaluation (ROSE) during EUS-guided FNA biopsy (EUS-FNAB) sampling may improve accuracy of pathologic analyses, cytopathologists are not widely available. We calculated the cutoff lengths required for accurate pathologic diagnoses from stereomicroscopically visible white cores (SVWCs) sampled using 22-gauge needles.

METHODS

Overall, 118 patients with mediastinal or upper abdominal solid masses requiring pathologic diagnoses were included. EUS-FNAB sampling was performed using 22-gauge needles. SVWCs were isolated and measured using stereomicroscopy, and the utility of calculated cutoff lengths in diagnosis was investigated.

RESULTS

The procedure success and SVWC sampling rates were both 100%, and the median SVWC length was 10 mm. Pathologic examination identified 75, 31, and 12 patients with pancreatic neoplasms (PNs), subepithelial lesions (SELs), and other lesions, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for diagnosing malignancy using EUS-FNAB sampling were 93.1%, 100%, 100%, 69.6%, and 94%, respectively. The final diagnostic accuracy in the entire cohort, PNs, and SELs was 92.4%, 90.7%, and 93.5%, respectively. Receiver operating characteristic curves demonstrated the overall SVWC cutoff length to be 11 mm (11 mm for PNs, 3.5 mm for SELs). The overall sensitivity according to SVWC cutoff length was 91.4% (87.6% for PNs, 98.8% for SELs). Compared with cutoff length, multivariate analysis confirmed SVWC length to be a stronger independent factor for tissue diagnosis in both groups.

CONCLUSIONS

Diagnosis improved significantly with SVWC cutoff lengths ≥11 mm. This may be a useful index for endoscopists, particularly where ROSE is unavailable. (Clinical trial registration number: UMIN000023013.).

Endoscopic features of gastrointestinal stromal tumor in the small intestine

Background/Aims

Gastrointestinal stromal tumor (GIST) is one of the most common types of submucosal tumors (SMTs). Because of GIST’s malignant potential, it is crucial to differentiate it from other SMTs. The present study aimed to identify characteristic endoscopic findings of GISTs in the small intestine.

Methods

We reviewed the clinicopathological and endoscopic findings of 38 patients with endoscopically or surgically resected SMTs in the small intestine. SMTs were classified into GIST and non-GIST groups, and clinicopathological and endoscopic findings were compared between the 2 groups.

Results

Fifteen patients had GIST and 23 patients had other types of SMTs in the small intestine. Comparison of the endoscopic findings between the 2 groups revealed that dilated vessels in the surrounding mucosa were significantly more in number in the GIST group than in the non-GIST group (P<0.05). However, there were no other differences in endoscopic findings between the 2 groups. Among patients with GISTs, the presence of dilated vessels in the surrounding mucosa was not associated with bleeding risk, tumor size, or metastasis rate at diagnosis.

Conclusions

Dilated vessels in the surrounding mucosa, identified during balloon-assisted endoscopy, may be a diagnostic indicator for GIST in the small intestine. However, its clinical significance should be further analyzed.

Efficacy of Mucosal Cutting Biopsy for the Histopathological Diagnosis of Gastric Submucosal Tumors

Background

Gastrointestinal stromal tumors occur frequently. Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is performed commonly for diagnosis. However, the success rate of histological diagnosis is insufficient when the submucosal tumor (SMT) is small. Recently, another technique, mucosal cutting biopsy (MCB) has been reported. The aim of this study is to evaluate the efficacy and safety of MCB.

Method

Between January 2012 and August 2018, MCB and EUS-FNA were performed 16 and 31 times for diagnosing gastric SMT. The diagnostic rate, the rate of successful immunohistochemistry, and the safety were reviewed. Difficult locations for EUS-FNA were also evaluated.

Results

The mean SMT sizes measured on MCB and EUS-FNA were 21.2 and 36.2 mm. The diagnostic rates of MCB and EUS-FNA were almost the same (88 vs. 81%), but successful immunohistochemistry was significantly higher in the MCB group (93 vs. 59%, p = 0.03). In the subgroup of SMTs < 20 mm, the successful histological diagnosis rate from EUS-FNA was relatively low. There were no complications. Failures of EUS-FNA were more frequent in the middle third of the stomach.

Conclusions

MCB was an effective procedure for diagnosing gastric SMT, especially in the case of small SMTs located at the middle third of the stomach.

Value of contrast-enhanced harmonic endoscopic ultrasonography in differentiating between gastrointestinal stromal tumors: A meta-analysis

OBJECTIVE

Contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) is a valuable device to diagnose and determine the malignant potential of gastrointestinal stromal tumors (GIST) as early as possible when making clinical therapeutic decisions. This study aimed to estimate the ability of CH-EUS to discriminate between GIST and benign submucosal lesions (SML) and to predict their malignant potential.

METHODS

PubMed, MEDLINE, EMBASE, the Web of Science, and Cochrane Central Register of Controlled Trials databases were screened. Using the data provided in the literatures, 2 × 2 tables were constructed to obtain the pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio. A receiver operating characteristic (ROC) curve was generated and the area under the ROC curve (AUROC) was calculated.

RESULTS

Four studies with a total of 187 patients were identified to evaluate the value of CH-EUS in discriminating between GIST and benign SML. The pooled sensitivity, specificity, and AUROC were 89% (95% CI 0.82-0.93), 82% (95% CI 0.66-0.92), and 0.89, respectively. Five studies including 143 patients were analyzed to assess the accuracy of CH-EUS in determining the malignant potential of GIST. The pooled sensitivity, specificity, and AUROC curve of CH-EUS were 96% (95% CI 0.90-0.99), 53% (95% CI 0.40-0.66), and 0.92, respectively.

CONCLUSIONS

CH-EUS is a safe, noninvasive method that can distinguish between GIST and benign subepithelial lesions and to predict their malignant potential to a certain extent. Large-scale, multicenter prospective studies are needed in the future.

Current clinical management of gastrointestinal stromal tumor

Gastrointestinal stromal tumors (GISTs) are the most common malignant subepithelial lesions (SELs) of the gastrointestinal tract. They originate from the interstitial cells of Cajal located within the muscle layer and are characterized by over-expression of the tyrosine kinase receptor KIT. Pathologically, diagnosis of a GIST relies on morphology and immunohistochemistry [KIT and/or discovered on gastrointestinal stromal tumor 1 (DOG1) is generally positive]. The prognosis of this disease is associated with the tumor size and mitotic index. The standard treatment of a GIST without metastasis is surgical resection. A GIST with metastasis is usually only treated by tyrosine kinase inhibitors without radical cure; thus, early diagnosis is the only way to improve its prognosis. However, a GIST is usually detected as a SEL during endoscopy, and many benign and malignant conditions may manifest as SELs. Conventional endoscopic biopsy is difficult for tumors without ulceration. Most SELs have therefore been managed without a histological diagnosis. However, a favorable prognosis of a GIST is associated with early histological diagnosis and R0 resection. Endoscopic ultrasonography (EUS) and EUS-guided fine needle aspiration (EUS-FNA) are critical for an accurate diagnosis of SELs. EUS-FNA is safe and effective in enabling an early histological diagnosis and adequate treatment. This review outlines the current evidence for the diagnosis and management of GISTs, with an emphasis on early management of small SELs.

EUS-guided sampling with 25G biopsy needle as a rescue strategy for diagnosis of small subepithelial lesions of the upper gastrointestinal tract

BACKGROUND AND STUDY AIMS

 This study was designed to evaluate the impact of additional tissue obtained with endoscopic ultrasound (EUS)-guided 25-gauge core biopsy needle (25G-PC) following an unsuccessful fine-needle biopsy (FNB) performed with larger-bore needles for the characterization of gastrointestinal subepithelial lesions (GI-SELs).

PATIENTS AND METHODS

 We prospectively collected and retrospectively analyzed information in our database from January 2013 to June 2017 for all patients with GI-SELs who received a EUS-guided FNB (EUS-FNB) with 25G-PC during the same procedure after failure of biopsy performed with larger-bore needle. Diagnostic yield, diagnostic accuracy and procedural complications were evaluated.

RESULTS

Sixteen patients were included in this study, 10 men and 6 women, median age 67.8 (range 43 to 76 years). Five patients were found to have a SEL localized in the distal duodenum, five in the gastric antrum, two in the gastric fundus and four in the gastric body. The mean size of the lesions was 20.5 mm (range 18 - 24 mm). EUS-FNB with 25G-PC enabled final diagnosis in nine patients (56.2 %). Regarding the subgroup of duodenal lesions, the procedure was successful in four of five (80 %). Final diagnoses with EUS-guided sampling were GIST (n = 6), leiomyoma (n = 2) and metastatic ovarian carcinoma (n = 1). No procedure-related complications were recorded.

CONCLUSION

 In patients with small GI-SELs, additional tissue obtained with 25G-PC could represents a "rescue" strategy after an unsuccessful procedure with larger-bore needles, especially when lesions are localized in the distal duodenum.

Maximizing the endosonography: The role of contrast harmonics, elastography and confocal endomicroscopy

New technologies in endoscopic ultrasound (EUS) evaluation have been developed because of the need to improve the EUS and EUS-fine needle aspiration (EUS-FNA) diagnostic rate. This paper reviews the principle, indications, main literature results, limitations and future expectations for each of the methods presented. Contrast-enhanced harmonic EUS uses a low mechanical index and highlights slow-flow vascularization. This technique is useful for differentiating solid and cystic pancreatic lesions and assessing biliary neoplasms, submucosal neoplasms and lymph nodes. It is also useful for the discrimination of pancreatic masses based on their qualitative patterns; however, the quantitative assessment needs to be improved. The detection of small solid lesions is better, and the EUS-FNA guidance needs further research. The differentiation of cystic lesions of the pancreas and the identification of the associated malignancy features represent the main indications. Elastography is used to assess tissue hardness based on the measurement of elasticity. Despite its low negative predictive value, elastography might rule out the diagnosis of malignancy for pancreatic masses. Needle confocal laser endomicroscopy offers useful information about cystic lesions of the pancreas and is still under evaluation for use with solid pancreatic lesions of lymph nodes.

In Vivo Endoluminal Ultrasound Biomicroscopy and Endoscopy of Inflamed Rat Esophagus

The development of high-frequency endoscopic ultrasound for the investigation of models of esophageal disease may offer insights for future translation to human imaging. With respect to small animal models of esophageal diseases, ultrasound imaging instrumentation must employ frequencies scaled up to maintain the compromise between image resolution and inspected region. In this sense, a 40-MHz endoluminal ultrasound biomicroscopy (eUBM) system and an endoscope were tested as diagnostic methods of imaging rat esophageal lesions in the acute and chronic phases caused by sodium hydroxide. Although endoscopy allowed grading of the esophagus in accordance with a classification specific to the epithelial alterations and including hyperemia, edema, exudates, fibrin and superficial and deep ulcerations, the eUBM images yielded the detection of superficial and deep ulcerations, as well as wall alterations caused by edema and inflammatory infiltrate in the submucosa. Additionally, eUBM enabled wall thickness measurements, which were statistically significantly increased (p < 0.05) in the acute phase.

Diagnostic and treatment strategy for small gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are considered to be potentially malignant mesenchymal tumors of the gastrointestinal tract. Clinically relevant GISTs are rare; however, subclinical GISTs (mini‐GISTs) (1‐2 cm) and pathologic GISTs (micro‐GISTs) (<1 cm) are frequently reported. Most mini‐GISTs and almost all micro‐GISTs of the stomach may exhibit benign clinical behavior, and only mini‐GISTs with high‐risk features may progress. For this review, a provisional algorithm was used to propose diagnostic and treatment strategies for patients with small GISTs. Because surgery is the only potentially curative treatment, in its application for small GISTs, the principles of sarcoma surgery should be maintained, and cost effectiveness should be considered. Indications for surgery include GISTs measuring ≥2 cm, symptomatic GISTs, and mini‐GISTs with high‐risk features (irregular borders, cystic spaces, ulceration, echogenic foci, internal heterogeneity, and tumor progression during follow‐up); however, a preoperative pathologic diagnosis is infrequently obtained. For small intestinal and colorectal GISTs, surgery is indicated irrespective of size because of their greater malignant potential. Otherwise, mini‐GISTs without high‐risk features, micro‐GISTs, and small submucosal tumors measuring <5 cm without high‐risk features may be followed by periodical endoscopic ultrasonography. Although surgical approaches and operative methods are selected according to tumor size, location, growth pattern, and surgical teams, laparoscopic surgery has produced similar oncologic outcomes and is less invasiveness compared with open surgery. After resection, pathologic examination for diagnosis and risk assessment is mandatory, and genotyping is also recommended for high‐risk GISTs. Endoscopic resection techniques, although feasible, are not routinely indicated for most mini‐GISTs or micro‐GISTs. Cancer 2016;122:3110–8. © 2016 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.

Gastrointestinal stromal tumors (GISTs) are potentially malignant, and endoscopic ultrasonography and endoscopic ultrasound‐guided fine‐needle aspiration may play a major role in the diagnosis of small GISTs and submucosal tumors. Surgery is indicated for all intestinal GISTs and for small gastric GISTs in patients who have symptoms and/or high‐risk features.

The diagnostic value of endoscopic ultrasonography and contrast-enhanced harmonic endoscopic ultrasonography in gastrointestinal stromal tumors

Objective:

To evaluate the diagnostic value of endoscopic ultrasonography (EUS) and contrast-enhanced harmonic (CEH) EUS in patients with gastrointestinal stromal tumors (GISTs).

Patients and Methods:

About 19 patients with suspected GISTs underwent EUS and CEH-EUS before tumor resection. The malignant potential was assessed according to the modified Fletcher classification system. Patients were divided into lower (Group I) and higher (Group II) malignant potential group. The clinical characteristics and EUS/CEH-EUS features were compared between two groups.

Results:

The tumor size in Group II was significantly larger than that in Group I (14.6 ± 5.8 mm vs. 32.1 ± 8.4 mm, P < 0.05). Heterogeneous echogenicity was observed in 4 (4/8) cases in Group II and none in Group I (P < 0.05). Irregular intratumoral vessels were detected in 6 cases in Group II and none in Group I (P < 0.05). The sensitivity and specificity of irregular vessel detection for discriminating higher from lower malignant potential GISTs were 75% and 100%, respectively. The positive predictive value and negative predictive value of detection of irregular vessels to high malignant potential GISTs were 33% and 100%, respectively.

Conclusion:

Detection of irregular intratumoral vessels can predict higher malignant potential before tumor resection. The tumor size and echogenicity are assistant factors for malignant potential assessment. Endoscopic resection is an efficacious treatment with good security for appropriate patients.

Small EUS-suspected gastrointestinal stromal tumors of the stomach: An overview for the current state of management

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors found in the gastrointestinal (GI) tract, with the stomach being the most common site. They represent a distinct group of GI tumors originating from the interstitial cells of Cajal and are characterized by gain-of-function mutations of KIT. KIT oncoprotein serves as both diagnostic and therapeutic targets. Prognosis is related to size, mitotic activity, and site of the tumor. Asymptomatic, small endoscopic ultrasonography (EUS)-suspected GISTs are increasingly encountered with the wide availability of endoscopic/endosonographic examination. The majority of small GISTs are biologically indolent, albeit possibly harboring c-KIT gene mutations. An ongoing controversy exists regarding the management and surveillance policy for small gastric GISTs. A number of reports on the management of GISTs have been published, not confidently addressing the issue of gastric GISTs of small size. This work provides an overview on the current state of management considerations, specifically focusing on small EUS-suspected gastric GISTs, which are increasingly encountered by clinicians.

Diagnostic potential of endoscopic ultrasonography-elastography for gastric submucosal tumors: A pilot study

BACKGROUND AND AIM

Qualitative diagnosis for gastric submucosal tumors (SMT) is not easy. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in combination with EUS-elastography (EUS-EG) is reported useful for qualitatively diagnosing pancreatic tissues. We prospectively studied whether EUS-EG could be useful in qualitative diagnosis of gastric SMT.

METHODS

We prospectively registered 25 consecutive patients with gastric SMT diagnosed by esophagogastroduodenoscopy and carried out qualitative evaluations using EUS-EG (May 2013 to March 2015) followed by histopathological diagnosis using EUS-FNA or endoscopic mucosal cutting biopsy. Elastic scores of gastric SMT were compared to the cytological diagnosis.

RESULTS

Of 25 patients, 22 had a confirmed cytological diagnosis. Regarding the Giovannini elastic score, of three patients with aberrant pancreas, one was score 1 and two were score 2; of eight patients with leiomyoma, seven were score 2 and one was score 3. Both of two patients with schwannoma were score 4. Of nine patients with gastrointestinal stromal tumor, six were score 4 and three were score 5. Gastrointestinal stromal tumor (GIST) is harder than other types of gastric SMT, and our study's findings suggested the usefulness of EUS-EG, which can also assess tumor hardness of gastric SMT.

CONCLUSION

EUS-EG might be helpful for the differential diagnosis of gastric SMT, especially to differentiate GIST from other SMT.

Therapy and follow-up of upper gastrointestinal subepithelial lesions

AIM: To explore the nature, growth, and malignant transformation of upper gastrointestinal submucosal lesions (SMLs), and evaluate the clinical efficacy, necessity and safety of surgery or endoscopic therapy for SMLs.

METHODS: We retrospectively collected 1915 cases of upper gastrointestinal submucous lesions, which were evaluated by endoscopic ultrasonography from January 2014 to December 2014 at our department. This diagnostic modality provided features about lesion location (esophagus and stomach), size, echo performance, layer of origin, etc. Different therapeutic methods were chosen according to the size, origin, and location of SMLs as well as patient's preferences. Clinical treatments included follow-up, endoscopic therapy (endoscopic snare resection, endoscopic resection, endoscopic submucosal resection, endoscopic submucosal dissection (ESD), endoscopic submucosal excavation (ESE), submucosal tunneling endoscopic resection, etc.), and surgery (open surgery, laparoscopy, and thoracoscopy). Endoscopic or surgical treatment of SMLs was performed when lesion size was significantly increased or suspected to have malignant transformation. Successful cases, size of the mass and layer of origin (mucosa layer, muscularis mucosa layer, submucosa layer, and serosal layer), complications (bleeding, perforation) and conversion surgery or not were recorded.

RESULTS: In 1135 cases followed by EUS, median age was 50.7 years ± 10.3 years (range, 19-78 years), and male/female ratio was 1.16. There were 687 esophageal SMLs and 448 gastric SMLs followed by regular endoscopy (range, 3-60 mo). Esophageal cases at initial measurement had a mean size of 0.82 cm ± 0.24 cm, and gastric cases had an initial mean size of 1.31 cm ± 0.44 cm. Of the followed cases of esophagus SMLs, 18 showed an obviously increased size (>2 cm), including 5 significantly increased cases (>3 cm) over a period of 6 mo and 13 moderately increased cases (>2 cm and <3 cm) during 12 mo. Surgical resection was performed in 5 lesions ≥3 cm in size, which were diagnosed as benign lesions in 3 (one leiomyoma and two cysts) and malignant lesions in 2 (1 leiomyosarcoma and 1 malignant granular cell tumor). Of the followed cases of gastric SMLs, 16 had an obviously increased size (>2 cm), including 10 significantly increased cases (>3 cm). Traditional surgery and endoscopic therapy were performed in 10 lesions ≥3 cm in size, which were diagnosed as gastrointestinal stromal tumors (GISTs) in 8 and leiomyomas in 2. A total of 780 cases underwent endoscopic or surgical therapy. Of 112 cases (19 esophageal cases and 93 gastric cases) treated by surgery, 2 (GIST and leiomyosarcoma) developed delayed bleeding, and the success rate of surgical treatment was 98.2%. Of 668 cases who underwent endoscopic therapy, 6 (4 in ESE group and 2 in ESD group) ended up with perforation and 4 of them (4 in ESE group) were converted to surgery; 2 (both in ESE group) developed intraoperative bleeding, which was managed by endoscopic spraying of drugs, electric coagulation and clips to achieve hemostasis; 2 cases in ESE group had failed dissection and then followed by EUS. The success rate of endoscopic therapy was 98.5%. Of 431 esophageal SMLs, there were 371 (86.08%) leiomyomas, 21 (4.87%) GISTs, and 13 (3.02%) cysts. Of 349 gastric SMLs, there were 168 (48.13%) GISTs, 87 (24.92%) leiomyomas, and 60 (17.91%) cases of ectopic pancreas.

CONCLUSION: No matter where the lesion is located, the esophagus or stomach, lesion size significantly increased over a period of 6 mo after initial measurement. However, few further change were observed in size, shape and EUS finding such as echo pattern or regularity of the outer margin over a period of 6-60 mo. Leiomyoma is the most common gastrointestinal SML in the esophagus, while GISTs are common in the stomach. Leiomyoma lesions rarely showed significant change as shown by endoscopic examination. Excessive medical therapy involves known issues associated with cost-effectiveness, patient compliance and risk of complications, and conservative treatment with regular clinical follow-up is recommended.

Comparison of Endoscopic and Open Resection for Small Gastric Gastrointestinal Stromal Tumor

The National Comprehensive Cancer Network recommends conservative follow-up for gastric gastrointestinal stromal tumors (GISTs) less than 2 cm. We have previously reported that the mitotic index of 22.22% of small gastric GISTs exceeded 5 per 50 high-power fields and recommended that all small gastric GISTs should be resected once diagnosed. The aim of the present study is to compare the safety and outcomes of endoscopic and open resection of small gastric GISTs. From May 2010 to March 2014, a total of 90 small gastric GIST patients were enrolled in the present study, including 40 patients who underwent surgical resection and 50 patients who underwent endoscopic resection. The clinicopathological characteristics, resection-related factors, and clinical outcomes were recorded and analyzed. The clinicopathological characteristics were comparable between the two groups except for tumor location and DOG-1 expression. Compared with the surgical resection group, the operation time was shorter (P = .000), blood loss was less (P = .000), pain intensity was lower (P < .05), duration of first flatus and defecation was shorter (P < .05), and medical cost of hospitalization was lower (P = .027) in the endoscopic resection group. The complications and postoperative hospital stay were comparable between the two groups. No in situ recurrence or liver metastasis was observed during follow-up. Endoscopic resection of small gastric GISTs is safe and feasible compared with surgical resection, although perforation could not be totally avoided during and after resection. The clinical outcome of endoscopic resection is also favorable.

Histological diagnosis of gastric submucosal tumors: A pilot study of endoscopic ultrasonography-guided fine-needle aspiration biopsy vs mucosal cutting biopsy

AIM: To compare the usefulness of endoscopic ultrasonography-guided fine-needle aspiration biopsy (EUS-FNAB) without cytology and mucosal cutting biopsy (MCB) in the histological diagnosis of gastric submucosal tumor (SMT).

METHODS: We prospectively compared the diagnostic yield, feasibility, and safety of EUS-FNAB and those of MCB based on endoscopic submucosal dissection. The cases of 20 consecutive patients with gastric SMT ≥ 1 cm in diameter. who underwent both EUS-FNAB and MCB were investigated.

RESULTS: The histological diagnoses were gastrointestinal stromal tumors (n = 7), leiomyoma (n = 6), schwannoma (n = 2), aberrant pancreas (n = 2), and one case each of glomus tumor, metastatic hepatocellular carcinoma, and no-diagnosis. The tumors’ mean size was 23.6 mm. Histological diagnosis was made in 65.0% of the EUS-FNABs and 60.0% of the MCBs, a nonsignificant difference. There were no significant differences in the diagnostic yield concerning the tumor location or tumor size between the two methods. However, diagnostic specimens were significantly more frequently obtained in lesions with intraluminal growth than in those with extraluminal growth by the MCB method (P = 0.01). All four SMTs with extraluminal growth were diagnosed only by EUS-FNAB (P = 0.03). No complications were found in either method.

CONCLUSION: MCB may be chosen as an alternative diagnostic modality in tumors showing the intraluminal growth pattern regardless of tumor size, whereas EUS-FNAB should be performed for SMTs with extraluminal growth.

Ectopic pancreas in the stomach successfully resected by endoscopic submucosal dissection

A 32-year-old Japanese man presented with a gastric submucosal tumor. Esophagogastroduodenoscopy showed a sessile submucosal tumor measuring approximately 10 mm in diameter on the greater curvature of the gastric antrum. Endoscopic ultrasonography examination revealed a solid tumor with a diameter of 11.8 mm, which was located in the deep mucosal and submucosal layers. The internal echogenicity was homogenous and hypoechoic. Biopsy examinations were performed twice but were not diagnostic since only the intact mucosal layer was obtained. The patient was subsequently diagnosed with ectopic pancreas in the stomach by endoscopic submucosal dissection (ESD). This case underscores the usefulness of the ESD technique for the pathological diagnosis of gastric submucosal tumors.