Discrepancy in diagnosis of gastric submucosal tumor among esophagogastroduodenoscopy, CT, and endoscopic ultrasonography: a retrospective analysis of 93 consecutive cases

EUS-Guided Diagnosis of Gastric Subepithelial Lesions, What Is New?

Gastric subepithelial lesions (SELs) are intramural lesions that arise underneath the gastric mucosa. SELs can be benign, but can also be malignant or have malignant potential. Therefore, correct diagnosis is crucial. Endosonography has been established as the diagnostic gold standard. Although the identification of some of these lesions can be carried out immediately, solely based on their echo characteristics, for certain lesions histological examination is necessary. Sometimes histology can be inconclusive, especially for smaller lesions. Therefore, new methods have been developed in recent years to assist decision making, such as contrast enhanced endosonography, EUS elastography, and artificial intelligence systems. In this narrative review we provide a complete overview of the gastric SELs and summarize the new data of the last ten years concerning the diagnostic advances of endosonography on this topic.

Single-incision needle-knife biopsy for the diagnosis of GI subepithelial tumors: a systematic review and meta-analysis

BACKGROUND AND AIMS

A histologic diagnosis of GI subepithelial tumors (SETs) is important because of the malignant potential of these lesions. The current modalities of choice, including EUS-guided FNA and biopsy (EUS-FNA/FNB) have demonstrated suboptimal diagnostic success. Single-incision with needle-knife (SINK) biopsy has emerged as an alternative diagnostic approach to increase tissue acquisition and diagnostic success. The aim of this study was to perform a systematic review and meta-analysis to evaluate the technical success, diagnostic success, and adverse events of SINK biopsy.

METHODS

We searched multiple databases including PubMed, EMBASE, CINAHL, Cochrane, Web of Science, and Google Scholar from inception to July 2022. The primary outcomes assessed were the technical success and diagnostic success of SINK in GI SETs. The secondary outcomes assessed were adverse events and whether immunohistochemical analysis could be successfully performed on tissue samples obtained via SINK.

RESULTS

Seven studies with a total of 219 SINK biopsy procedures were included in this meta-analysis. The technical success rate was 98.1% (95% CI, 94.9%-99.3%; P = .000; I² = .0%), and the diagnostic success rate was 87.9% (95% CI, 82.6%-91.7%; P = .000; I² = .0%). The immunohistochemical success rate was 88.3% (95% CI, 78.7%-93.9%; P = .000; I² = 3.5%). The rate of adverse events was 7.5% (95% CI, 4.3%-12.7%; P = .00; I² = 7.2%), and bleeding was the most common adverse event.

CONCLUSION

SINK biopsy is a safe diagnostic procedure with a high technical and diagnostic success in patients with GI SET. Further randomized controlled trials and direct comparison studies are needed to validate these findings.

Risk stratification for 1- to 2-cm gastric gastrointestinal stromal tumors: visual assessment of CT and EUS high-risk features versus CT radiomics analysis

OBJECTIVES

To investigate the ability of CT and endoscopic sonography (EUS) in predicting the malignant risk of 1-2-cm gastric gastrointestinal stromal tumors (gGISTs) and to clarify whether radiomics could be applied for risk stratification.

METHODS

A total of 151 pathologically confirmed 1-2-cm gGISTs from seven institutions were identified by contrast-enhanced CT scans between January 2010 and March 2021. A detailed description of EUS morphological features was available for 73 gGISTs. The association between EUS or CT high-risk features and pathological malignant potential was evaluated. gGISTs were randomly divided into three groups to build the radiomics model, including 74 in the training cohort, 37 in validation cohort, and 40 in testing cohort. The ROIs covering the whole tumor volume were delineated on the CT images of the portal venous phase. The Pearson test and least absolute shrinkage and selection operator (LASSO) algorithm were used for feature selection, and the ROC curves were used to evaluate the model performance.

RESULTS

The presence of EUS- and CT-based morphological high-risk features, including calcification, necrosis, intratumoral heterogeneity, irregular border, or surface ulceration, did not differ between very-low and intermediate risk 1-2-cm gGISTs (p > 0.05). The radiomics model consisting of five radiomics features showed favorable performance in discrimination of malignant 1-2-cm gGISTs, with the AUC of the training, validation, and testing cohort as 0.866, 0.812, and 0.766, respectively.

CONCLUSIONS

Instead of CT- and EUS-based morphological high-risk features, the CT radiomics model could potentially be applied for preoperative risk stratification of 1-2-cm gGISTs.

KEY POINTS

• The presence of EUS- and CT-based morphological high-risk factors, including calcification, necrosis, intratumoral heterogeneity, irregular border, or surface ulceration, did not correlate with the pathological malignant potential of 1-2-cm gGISTs. • The CT radiomics model could potentially be applied for preoperative risk stratification of 1-2-cm gGISTs.

Multifeature Fusion Classification Method for Adaptive Endoscopic Ultrasonography Tumor Image

Endoscopic ultrasonography (EUS) has been found to be of great advantage in the diagnosis of digestive tract submucosal tumors. However, EUS-based diagnosis is limited by variability in subjective interpretation on the part of doctors. Tumor classification of ultrasound images with the computer-aided diagnosis system can significantly improve the diagnostic efficiency and accuracy of doctors. In this study, we proposed a multifeature fusion classification method for adaptive EUS tumor images. First, for different ultrasound tumor images, we selected the region of interest based on prior information to facilitate the estimation in the subsequent works. Second, we proposed a method based on image gray histogram feature extraction with principal component analysis dimensionality reduction, which learns the gray distribution of different tumor images effectively. Third, we fused the reduced grayscale features with the improved local binary pattern features and gray-level co-occurrence matrix features, and then used the multiclassification support vector machine. Finally, in the experiment, we selected the 431 ultrasound images of 109 patients in the hospital and compared the experimental effects of different features and different classifiers. The results revealed that the proposed method performed best, with the highest accuracy of 96.18% and an area under the curve of 99%. It is evident that the method proposed in this study can efficiently contribute to the classification of EUS tumor images.

ACG Clinical Guideline: Diagnosis and Management of Gastrointestinal Subepithelial Lesions

Subepithelial lesions (SEL) of the GI tract represent a mix of benign and potentially malignant entities including tumors, cysts, or extraluminal structures causing extrinsic compression of the gastrointestinal wall. SEL can occur anywhere along the GI tract and are frequently incidental findings encountered during endoscopy or cross-sectional imaging. This clinical guideline of the American College of Gastroenterology was developed using the Grading of Recommendations Assessment, Development, and Evaluation process and is intended to suggest preferable approaches to a typical patient with a SEL based on the currently available published literature. Among the recommendations, we suggest endoscopic ultrasound (EUS) with tissue acquisition to improve diagnostic accuracy in the identification of solid nonlipomatous SEL and EUS fine-needle biopsy alone or EUS fine-needle aspiration with rapid on-site evaluation sampling of solid SEL. There is insufficient evidence to recommend surveillance vs resection of gastric gastrointestinal stromal tumors (GIST) <2 cm in size. Owing to their malignant potential, we suggest resection of gastric GIST >2 cm and all nongastric GIST. When exercising clinical judgment, particularly when statements are conditional suggestions and/or treatments pose significant risks, health-care providers should incorporate this guideline with patient-specific preferences, medical comorbidities, and overall health status to arrive at a patient-centered approach.

Advances in endoscopic resection techniques of small gastric tumors originating from the muscularis propria

Gastrointestinal stromal tumors are common gastrointestinal tumors typically originating from the muscularis propria layer of the stomach. Small gastric stromal tumors are usually detected incidentally during routine endoscopic examination. Although they may have malignant potentially, controversies remain regarding the need for endoscopic resection of small gastric stromal tumors originating from the muscularis propria. According to the guidelines of the European Society of Medical Oncology, all gastrointestinal stromal tumors >2 cm in size should be resected with endoscopic surveillance recommended for tumors <2 cm. Endoscopic resection including endoscopic mucosal dissection (EMD), endoscopic submucosal dissection (ESD), submucosal tunneling endoscopic resection and snare assisted endoscopic resection. However, EMD and ESD procedures may be accompanied with serious complications including perforation, bleeding, and abdominal infection. Snare-assisted endoscopic resection is an alternative approach and has the advantages of a shorter procedure time and a low rate of perforation or bleeding. This study summarizes the safety and feasibility of a novel snare-assisted endoscopic resection technique and highlights the pros and cons of the different endoscopic approaches currently used for subepithelia small gastric tumors.

Application of Endoscopic Ultrasound Combined with Multislice Spiral CT in Diagnosis and Treatment of Patients with Gastrointestinal Eminence Lesions

Objective

To evaluate the application of endoscopic ultrasound (EUS) combined with multislice spiral CT (MSCT) in the diagnosis and treatment of patients with gastric eminence lesions.

Methods

A total of 160 patients with gastric eminence lesions enrolled in our hospital from June 2018 to June 2021 were included and received EUS and MSCT. The results of the two examinations and the postoperative pathological results were compared.

Results

The common pathological types of gastric eminence lesions include polyps and stromal tumors, with the most common sites of lesions in the gastric antrum, followed by the fundus of the stomach and the gastric body. Gastric eminence lesions mostly originate from the mucosal layer and muscularis mucosa, accounting for 83.13% of the total. With pathological results as the gold standard, the detection rate of MSCT was 90.63%, and that of EUS was 78.13%. With the joint diagnosis as a reference, the receiver operating curve (ROC) revealed a higher diagnostic efficiency of MSCT and EUS.

Conclusion

The accuracy of MSCT in the diagnosis of gastric eminence lesions is significantly higher than that of EUS, both of which can offer useful guidance for the choice of endoscopic treatment methods. The combination of MSCT and EUS examination before endoscopic gastroscopy may provide a better treatment efficacy on gastric protruding lesions with high safety.

Advancements in the Diagnosis of Gastric Subepithelial Tumors

A diagnosis of subepithelial tumors (SETs) is sometimes difficult due to the existence of overlying mucosa on the lesions, which hampers optical diagnosis by conventional endoscopy and tissue sampling with standard biopsy forceps. Imaging modalities, by using computed tomography and endoscopic ultrasonography (EUS) are mandatory to noninvasively collect the target's information and to opt candidates for further evaluation. Particularly, EUS is an indispensable diagnostic modality for assessing the lesions precisely and evaluating the possibility of malignancy. The diagnostic ability of EUS appears increased by the combined use of contrast-enhancement or elastography. Histology is the gold standard for obtaining the final diagnosis. Tissue sampling requires special techniques to break the mucosal barrier. Although EUS-guided fine-needle aspiration (EUS-FNA) is commonly applied, mucosal cutting biopsy and mucosal incision-assisted biopsy are comparable methods to definitively obtain tissues from the exposed surface of lesions and seem more useful than EUS-FNA for small SETs. Recent advancements in artificial intelligence (AI) have a potential to drastically change the diagnostic strategy for SETs. Development and establishment of noninvasive methods including AI-assisted diagnosis are expected to provide an alternative to invasive, histological diagnosis.

Could computed tomography be used as a surrogate of endoscopic ultrasonography in the screening and surveillance of small gastric Gastrointestinal stromal tumors?

PURPOSE

To investigate whether computed tomography (CT) could be used for screening and surveillance of small gastric gastrointestinal stromal tumors (gGISTs).

METHOD

A total of 162 pathologically confirmed small gGISTs (≤2 cm) between September 2007 and November 2019 were retrospectively enrolled. Thirty-six lesions received contrast-enhanced CT after they were identified by endoscopy and EUS, and forty-three lesions received CT alone before surgery. The detection rate of CT for ≤1 cm gGISTs (micro-gGISTs) and 1-2 cm gGISTs (mini-gGISTs) was investigated, and the detection rate of CT alone was compared with that of CT following endoscopy and EUS. The relationship between EUS- and CT-detected high-risk features were assessed.

RESULTS

CT demonstrated a favorable detection rate for mini-gGISTs previously identified by EUS and endoscopy, whereas CT alone showed an inferior detection rate (100 % vs. 75 %, p =  0.02). CT showed a poor detection rate for micro-gGISTs, both for lesions received CT after identified by EUS and endoscopy, and those received CT alone (33.3 % vs. 14.8 %, p =  0.372). CT-detected heterogeneous enhancement pattern and presence of calcification were strongly correlated with heterogeneous echotexture (Spearman's ρ=0.66, p < 0.001) and echogenic foci (Spearman's ρ=0.79, p < 0.001) on EUS, respectively. CT-detected necrosis was moderately correlated with cystic spaces on EUS (Spearman's ρ=0.42, p = 0.02). No correlation was found between EUS- and CT- assessed irregular border.

CONCLUSIONS

CT could potentially be considered as a surrogate of EUS for surveillance of mini-gGISTs instead of micro-gGISTs, whereas couldn't be used as a screening modality for either micro- or mini-gGISTs.

Clinical Efficacy of Single-Channel Gastroscopy, Double-Channel Gastroscopy, and Double Gastroscopy for Submucosal Tumors in the Cardia and Gastric Fundus

OBJECTIVE

To determine the feasibility and efficacy of single-channel gastroscopy, double-channel gastroscopy, and double gastroscopy in treating submucosal tumors in the cardia and gastric fundus.

METHODS

The data of 77 patients with submucosal tumors (SMTs) in the cardia and gastric fundus parts of the stomach who underwent single-channel gastroscopy, double-channel gastroscopy, and double gastroscopy were retrospectively analyzed. The observed therapeutic effect, complications, and local recurrence from these three groups were then compared.

RESULTS

All lesions were completely taken out under endoscopy, and the operation time for single-channel gastroscopy group was 20-90 min with an average of 44.5 min, and the postoperative hospitalization time was 5-9 days with an average of 7.5 days. The operation time for the double-channel gastroscopy group was 40-110 min with an average of 60.5 min, and the postoperative hospitalization time was 7-10 days with an average of 8.3 days, whereas the operation time of double gastroscopy group was 35-120 min with an average of 66.3 min, and the postoperative hospitalization time was 7-10 days with an average of 8.5 days. No patient was required to be transferred to the General Surgery Department for continuous treatment. Bleeding was noted from all the patients during operation, and hemostasis was performed successfully. Postoperative bleeding was not observed in any of the cases. Full-thickness resection was performed in all the three groups. No residual or recurrent lesions were detected via reexamination of gastroscopy in all the patients.

CONCLUSION

Single-channel gastroscopy, double-channel gastroscopy, and double gastroscopy present potential capability with distinctive advantages in the endoscopic treatment of submucosal tumors of the cardia and gastric fundus, and it also shows that appropriate operation methods should be selected based on the situation of an individual patient.

Comparison of the Diagnostic Ability of Endoscopic Ultrasonography and Abdominopelvic Computed Tomography in the Diagnosis of Gastric Subepithelial Tumors

Background/Aims

Endoscopic ultrasonography (EUS) is the most efficient imaging modality for gastric subepithelial tumors (SETs). However, abdominopelvic computed tomography (APCT) has other advantages in evaluating the characteristics, local extension, or invasion of SETs to adjacent organs. This study aimed to compare the diagnostic ability of EUS and APCT based on surgical histopathology results.

Methods

We retrospectively reviewed data from 53 patients who underwent both EUS and APCT before laparoscopic wedge resection for gastric SETs from January 2010 to December 2017 at a single institution. On the basis of histopathology results, we assessed the diagnostic ability of the 2 tests.

Results

The overall accuracy of EUS and APCT was 64.2% and 50.9%, respectively. In particular, the accuracy of EUS vs. APCT for the diagnosis of gastrointestinal stromal tumors (GISTs), leiomyomas, and ectopic pancreas was 83.9% vs. 74.2%, 37.5% vs. 0.0%, and 57.1% vs. 14.3%, respectively. Most of the incorrect diagnoses with EUS involved hypoechoic lesions originating in the fourth echolayer, with the most common misdiagnosed lesions being GISTs mistaken for leiomyomas and vice versa.

Conclusions

APCT showed a lower overall accuracy than EUS; however, APCT remains a useful modality for malignant/potentially malignant gastric SETs.

CT Versus Endoscopic Ultrasound for Differentiating Small (2-5 cm) Gastrointestinal Stromal Tumors From Leiomyomas

OBJECTIVE. Abdominal CT or endoscopic ultrasound is recommended for the evaluation of gastric subepithelial tumors. However, few studies have compared the diagnostic performance of these two methods. We compared the diagnostic performance of CT versus endoscopic ultrasound for gastric subepithelial tumors smaller than 5 cm. We also identified significant CT findings associated with the diagnosis of gastrointestinal stromal tumors. MATERIALS AND METHODS. Seventy-one patients with pathologically proven gastric subepithelial tumors were enrolled. We examined the diagnostic performance of CT compared with endoscopic ultrasound. We analyzed CT findings, including the location, long diameter (LD), short diameter (SD), LD-SD ratio, contour, margin, growth pattern, degree and pattern of enhancement, attenuation value, intralesional necrosis, calcification, hemorrhage, surface dimpling, and perilesional lymph node. RESULTS. Endoscopic ultrasound had a sensitivity of 77.6%, specificity of 61.5%, PPV of 90.0%, NPV of 38.1%, and accuracy of 74.6%. CT had a sensitivity of 84.5%, specificity of 53.8%, PPV of 89.1%, NPV of 43.8%, and accuracy of 78.9%. Multivariate analysis revealed that the presence of intralesional necrosis (odds ratio [OR], 10.88; p = 0.037) and an LD-SD ratio less than 1.5 (OR, 32.37; p = 0.002) were independent CT findings for the diagnosis of gastrointestinal stromal tumors. CONCLUSION. CT is as effective as endoscopic ultrasound for the diagnosis of gastric subepithelial tumors smaller than 5 cm. Tumors with intralesional necrosis and an LD-SD ratio less than 1.5 may require further pathologic diagnosis.

Diagnostic performance of stomach CT compared with endoscopic ultrasonography in diagnosing gastric subepithelial tumors

PURPOSE

To evaluate the diagnostic ability of multi-detector computed tomography (MDCT) compared to endoscopic ultrasonography (EUS) as a standard reference, and investigate the factors influencing the detection of small gastric subepithelial tumors (SETs) (<5 cm) on MDCT with stomach protocol.

METHODS

We retrospectively investigated 70 patients who were suspected with gastric SETs on esophagogastroduodenoscopy (EGD), and underwent both EUS and computed tomographic (CT) scanning. EUS was performed by two gastroenterologists, and location, size, echotexture, echogenicity, and layer of origin were described when gastric SETs were detected on EUS. MDCTs were reviewed based on consensus of two radiologists blinded to the EUS result. Size, location, enhancement pattern, and contour of the lesion detected on CT were described. We calculated the diagnostic ability of CT compared to EUS with respect to detection of gastric SETs, and investigated the factors influencing detection of SETs on CT. We also used receiver operating characteristic (ROC) curve to obtain optimal cut-off size for predicting CT visibility of small SETs.

RESULTS

Of the 70 patients, who underwent both CT and EUS due to suspicious presence of SET on EGD, EUS detected 56 probable cases of SET and 14 cases of external compression. CT led to detection of 39 cases of SET out of the 56 cases. Sensitivity and specificity of CT was 69.6% and 100.0%, respectively. Positive predictive value (PPV) and negative predictive value (NPV) of CT were 100.0% and 45.2%, respectively. There was a significant difference in mean size of CT-detected lesions compared to CT-invisible lesions (14.36 mm vs. 8.52 mm, p < 0.001), but no significant differences in terms of layer of origin and location between these two groups (p > 0.5) were observed. The ROC analysis revealed that the optimal cut-off value, also referred to prediction of CT visibility, was 10 mm. Out of 70 cases, 26 cases (37.14%) were identified as external compression or insignificant lesions such as lipoma, hemangioma, lymphangioma, or gastritis cystica on CT, and do not require regular follow-up.

CONCLUSIONS

Stomach CT shows good feasibility with respect to depiction of small SETs, especially in cases where size is larger than 10 mm. Henceforth, it is proposed that stomach CT would be a complimentary or problem-solving tool for SET in evaluating the presence of external compression and characterization of tumors.

Rapid On-Site Evaluation by Endosonographers during Endoscopic Ultrasonography-Guided Fine-Needle Aspiration for Diagnosis of Gastrointestinal Stromal Tumors

BACKGROUND/AIMS

Endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) has been used to diagnose gastrointestinal submucosal tumors (SMTs). Although rapid on-site evaluation (ROSE) has been reported to improve the diagnostic accuracy of EUS-FNA for pancreatic lesions, on-site cytopathologists are not routinely available. Given this background, the usefulness of ROSE by endosonographers themselves for pancreatic tumors has also been reported. However, ROSE by endosonographers for diagnosis of SMT has not been reported. The aim of this study was to evaluate the diagnostic accuracy of EUS-FNA with ROSE by endosonographers for SMT, focusing on diagnosis of gastrointestinal stromal tumor (GIST), compared with that of EUS-FNA alone.

METHODS

Twenty-two consecutive patients who underwent EUS-FNA with ROSE by endosonographers for SMT followed by surgical resection were identified. Ten historical control subjects who underwent EUS-FNA without ROSE were used for comparison.

RESULTS

The overall diagnostic accuracy for SMT was significantly higher in cases with than without ROSE (100% vs. 80%, p=0.03). The number of needle passes by FNA with ROSE by endosonographers tended to be fewer, although accuracy was increased (3.3±1.3 vs. 5.9±3.8, p=0.06).

CONCLUSIONS

ROSE by endosonographers during EUS-FNA for SMT is useful for definitive diagnosis, particularly for GIST.

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.

Endoscopic ultrasound-guided fine-needle aspiration skill acquisition of gastrointestinal submucosal tumor by trainee endoscopists: A pilot study

BACKGROUND AND OBJECTIVES

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is an effective method for tissue diagnosis of gastrointestinal submucosal tumors (SMTs) that are difficult to diagnose by standard endoscopic biopsy. However, the learning curve, especially for gastrointestinal SMT, has not been sufficiently established. The aim of our study was to assess the skill acquisition and diagnostic accuracy of EUS-FNA for gastrointestinal SMT in trainee endoscopists in order to elucidate the optimal starting standards of EUS-FNA.

MATERIALS AND METHODS

We prospectively evaluated 51 EUS-FNA procedures for gastrointestinal SMT between May 2010 and March 2014. The procedure was performed by two trainee endoscopists and two expert endoscopists. We investigated the diagnostic yield of EUS-FNA and the factors associated with the accuracy between the trainee endoscopists and expert endoscopists.

RESULTS

The rate of adequate EUS-FNA materials for histological examination was 86.3%. Although infections occurred in two cases (3.9%), which were managed conservatively, no severe complications were identified. Comparing the trainee endoscopists with expert endoscopists, there was no significant difference in the rate of gaining adequate specimen (76.5% vs. 82.3%, P = 0.4626). However, the mean number of passes of the trainees tended to be more than that of the expert endoscopists (2.1 pass vs. 1.7 pass, P = 0.0511), and lesions located in the middle third of the stomach were the predictive factors for nondiagnostic tumors by the trainee endoscopists (P = 0.0075).

CONCLUSION

EUS-FNA for gastrointestinal SMT by trainee endoscopists can be safely performed under the supervision of EUS-FNA expert endoscopists.

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.

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.

Expanding indications for ESD: submucosal disease (SMT/carcinoid tumors)

Endoscopic submucosal dissection (ESD) is useful for submucosal tumors (SMTs) within the superficial submucosal layer, but perforation frequently occurs during ESD for SMTs located at the deeper layer. Endoscopic resection for small esophageal SMTs is acceptable, although candidates for endoscopic removal are rare. Laparoscopic assistance will be effective for minimally invasive endoscopic local resection for certain types of gastric SMT. Endoscopic mucosal resection with a ligation device would be better than ESD for rectal carcinoid in terms of simplicity and effectiveness.

Submucosal tumors: comprehensive guide for the diagnosis and therapy of gastrointestinal submucosal tumors

Small submucosal tumors (SMT) without symptoms are frequently found by endoscopic and radiological examinations. To find proper diagnostic measures and therapeutic indications for histologically undiagnosed SMT, we reviewed published articles in PubMed between 1990 and March 2013 using the key words 'submucosal tumor' and the name of a specific disease. SMT is observed in a wide range of gastrointestinal (GI) diseases and conditions, including compression by extra-GI organs and lesions, congenital tumors, inflammation, and benign as well as malignant neoplastic lesions. In the diagnosis of diseases and decision-making for therapy, endoscopic ultrasonography (EUS) and endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) may play a key role. Symptomatic SMT and SMT histologically diagnosed as malignant or potentially malignant tumors such as gastrointestinal stromal tumor (GIST) should be treated by surgery. SMT >5 cm, SMT increasing in size and those with'high-risk features' including irregular border, heterogeneous internal echo such as anechoic area, and heterogeneous enhancement by contrast media may also be removed by surgery. Laparoscopic approach is feasible for gastric GIST <5 cm and this is considered less invasive than the open approach. Emerging techniques using flexible endoscopes appear less invasive, but require further evidence and are still under clinical study. Correct diagnosis of SMT is challenging; however, EUS and EUS-FNA are useful in the histological diagnosis and clinical decision-making. In the future, minimally invasive approaches may be a mainstream of surgical treatment for small SMT.

Surgical treatment of gastric gastrointestinal stromal tumor

Gastrointestinal stromal tumor is the most common mesenchymal tumor in the gastrointestinal tract and is most frequently developed in the stomach in the form of submucosal tumor. The incidence of gastric gastrointestinal stromal tumor is estimated to be as high as 25% of the population when all small and asymptomatic tumors are included. Because gastric gastrointestinal stromal tumor is not completely distinguished from other submucosal tumors, a surgical excisional biopsy is recommended for tumors >2 cm. The surgical principles of gastrointestinal stromal tumor are composed of an R0 resection with a normal mucosa margin, no systemic lymph node dissection, and avoidance of perforation, which results in peritoneal seeding even in cases with otherwise low risk profiles. Laparoscopic surgery has been indicated for gastrointestinal stromal tumors <5 cm, and the indication for laparoscopic surgery is expanded to larger tumors if the above mentioned surgical principles can be maintained. A simple exogastric resection and various transgastric resection techniques are used for gastrointestinal stromal tumors in favorable locations (the fundus, body, greater curvature side). For a lesion at the gastroesophageal junction in the posterior wall of the stomach, enucleation techniques have been tried preserve the organ's function. Those methods have a theoretical risk of seeding a ruptured tumor, but this risk has not been evaluated by well-designed clinical trials. While some clinical trials are still on-going, neoadjuvant imatinib is suggested when marginally unresectable or multiorgan resection is anticipated to reduce the extent of surgery and the chance of incomplete resection, rupture or bleeding.