EUS-guided sampling of suspected GI stromal tumors

English version of Japanese Clinical Practice Guidelines 2022 for gastrointestinal stromal tumor (GIST) issued by the Japan Society of Clinical Oncology

The Japan Society of Clinical Oncology Clinical Practice Guidelines 2022 for gastrointestinal stromal tumor (GIST) have been published in accordance with the Minds Manual for Guideline Development 2014 and 2017. A specialized team independent of the working group for the revision performed a systematic review. Since GIST is a rare type of tumor, clinical evidence is not sufficient to answer several clinical and background questions. Thus, in these guidelines, we considered that consensus among the experts who manage GIST, the balance between benefits and harms, patients' wishes, medical economic perspective, etc. are important considerations in addition to the evidence. Although guidelines for the treatment of GIST have also been published by the National Comprehensive Cancer Network (NCCN) and the European Society for Medical Oncology (ESMO), there are some differences between the treatments proposed in those guidelines and the treatments in the present guidelines because of the differences in health insurance systems among countries.

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.

Gastric schwannoma: The gastrointestinal tumor simulator - case report and review of the literature

INTRODUCTION AND IMPORTANCE

Gastric schwannoma is a rare and benign tumor originating from the peripheral nerves of the stomach. Despite its benign nature, this tumor typically remains asymptomatic for an extended period, and its radiological and endoscopic presentation poses challenges in distinguishing it from other gastric mesenchymal tumors.

CASE PRESENTATION

Here, we present a rare case of a patient experiencing gastric pain and melena secondary to a gastric mass. The initial preoperative diagnosis indicated a gastrointestinal stromal tumor, but subsequent pathological and immunohistochemical staining of the surgical specimen confirmed the presence of gastric schwannoma.

DISCUSSION

To gain insights into this uncommon condition, we conducted an electronic search on PubMed using the keywords "gastric schwannoma" and "gastric neurinoma." Our focus centered on case series containing more than five cases of gastric localization, resulting in the analysis of 14 case series involving a total of 321 patients. Our review aims to comprehensively discuss the clinical, radiological, and therapeutic aspects associated with this rare disease.

CONCLUSION

In the absence of a definitive preoperative diagnosis, the surgical approach is considered the primary treatment for resectable gastric schwannoma, given its excellent long-term outcomes. However, further studies are imperative to better define the role of endoscopic resection in managing this condition.

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.

Endoscopic Ultrasound Advanced Techniques for Diagnosis of Gastrointestinal Stromal Tumours

Gastrointestinal Stromal Tumors (GISTs) are subepithelial lesions (SELs) that commonly develop in the gastrointestinal tract. GISTs, unlike other SELs, can exhibit malignant behavior, so differential diagnosis is critical to the decision-making process. Endoscopic ultrasound (EUS) is considered the most accurate imaging method for diagnosing and differentiating SELs in the gastrointestinal tract by assessing the lesions precisely and evaluating their malignant risk. Due to their overlapping imaging characteristics, endosonographers may have difficulty distinguishing GISTs from other SELs using conventional EUS alone, and the collection of tissue samples from these lesions may be technically challenging. Even though it appears to be less effective in the case of smaller lesions, histology is now the gold standard for achieving a final diagnosis and avoiding unnecessary and invasive treatment for benign SELs. The use of enhanced EUS modalities and elastography has improved the diagnostic ability of EUS. Furthermore, recent advancements in artificial intelligence systems that use EUS images have allowed them to distinguish GISTs from other SELs, thereby improving their diagnostic accuracy.

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.

A Gastroenterologist's Approach to the Diagnosis and Management of Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal (GI) tract. These tumors have been shown to harbor oncogenic mutations of the c-kit tyrosine kinase receptor or platelet-derived growth factor receptor alpha (PDGFRA). Immunohistochemical analysis of GISTs allows for the differentiation of these tumors from other mesenchymal tumors of the GI tract such as leiomyomas and leiomyosarcomas. All GISTs have the potential to behave in a malignant fashion. Tumor location, size, and mitotic index are factors used to predict the risk of malignant behavior. Endoscopy and endoscopic ultrasound play a critical role in the diagnosis of GISTs and can yield important information to further risk-stratify tumors and determine management. This article provides a gastroenterologist's perspective on the diagnosis and management of GISTs.

A Meta-Analysis Comparing Endoscopic Ultrasound-guided Fine-needle Aspiration With Endoscopic Ultrasound-guided Fine-needle Biopsy

BACKGROUND

The superiority between endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) and endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) is still a debate. The purpose of this meta-analysis was to compare the diagnostic value and safety of these 2 needles in sampling of all solid lesions and separately pancreatic lesions.

MATERIALS AND METHODS

PubMed, EMBASE, and the Cochrane library were searched for randomized controlled studies that reported the comparison of FNA and FNB in solid mass. Outcome measures included diagnostic accuracy, number of needle passes, diagnostic adequacy, presence of tissue cores, and adverse events. Standard error, upper and lower confidence intervals at 95% confidence interval for the risk were obtained using Review Manager Version 5.3 which was also used to generate forest plots for pooled analysis. The random or fixed effect model was applied depending on the heterogeneity ( I2 ).

RESULTS

Eighteen randomized control trial studies with a total of 2718 patients (1141 patients with EUS-FNA, 1108 with EUS-FNB, and remaining 469 patients were sampled with both needles alternatively) were included in the meta-analysis.FNB group has relatively good diagnostic accuracy relative risk (RR): 0.94, 0.92-0.97; P =0.0002), diagnostic adequacy (RR: 0.95, 0.9-1.0; P =0.04) and high quality histologic yield compared (RR: 0.77, 0.64-0.93; P =0.007) with the FNA group in solid gastrointestinal lesions, and the number of needle passes to obtain sufficient tissue (mean difference: 0.54, 0.45-0.64; P <0.00001) was lower in the FNB group. For solid pancreatic disease only, there was no difference in diagnostic accuracy (RR: 0.97, 0.93-1.01, P =0.13) or quality histologic yield (RR: 0.60, 0.29-1.23; P =0.16). The rate of adverse events (RR: 1.04, 0.48-2.29; P =0.92) did not significantly differ between FNA and FNB groups.

CONCLUSIONS

In solid gastrointestinal lesions, FNB is associated with a relatively better diagnostic adequacy, diagnostic adequacy and tissue cores rates, and less number of needle passes. For solid pancreatic disease only, there is no difference in diagnostic accuracy or tissue cores rates.

Comparison of diagnostic performances of slow-pull suction and standard suction in endoscopic ultrasound-guided fine needle biopsy for gastrointestinal subepithelial tumors

Background/Aims

Endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) is integral to the diagnosis of gastrointestinal (GI) subepithelial tumors (SETs). The impact of different EUS-FNB tissue sampling techniques on specimen adequacy and diagnostic accuracy in SETs has not been fully evaluated. This study aimed to compare the diagnostic outcomes of slow-pull (SP) and standard suction (SS) in patients with GI SETs.

Methods

In this retrospective comparative study, 54 patients were enrolled. Medical records were reviewed for location and size of the target lesion, FNB needle type/size, technical order, specimen adequacy, diagnostic yield, and adverse events. The acquisition rate of adequate specimens and diagnostic accuracy were compared according to EUS-FNB techniques.

Results

The mean lesion size was 42.6±36.4 mm, and most patients were diagnosed with GI stromal tumor (75.9%). The overall diagnostic accuracies of the SP and SS techniques were 83.3% and 81.5%, respectively (p=0.800). The rates of obtaining adequate core tissue were 79.6% and 75.9%, respectively (p=0.799). No significant clinical factors affected the rate of obtaining adequate core tissue, including lesion location and size, FNB needle size, and final diagnosis.

Conclusions

SP and SS had comparable diagnostic accuracies and adequate core tissue acquisition for GI SETs via EUS-FNB.

Tissue diagnosis necessary for small endoscopic ultrasound-suspected gastric gastrointestinal stromal tumors 2 cm or less in size: A prospective study focusing on the endoscopic incisional biopsy

BACKGROUND AND AIM

The small endoscopic ultrasound (EUS)-suspected gastric gastrointestinal stromal tumors (GISTs), gastric subepithelial tumors at the muscularis propria layer on EUS, are detected frequently. Bite-on-bite forceps biopsy and EUS-guided tissue sampling yield variable results. This study aimed to analyze clinicopathologic features of the small EUS-suspected gastric GISTs 2 cm or less in size and to evaluate the efficacy and safety of the endoscopic incisional biopsy (EIB) for these small tumors.

METHODS

This prospective study investigated 70 patients with small EUS-suspected gastric GISTs 2 cm or less in size in two stages. Firstly, 30 patients were recruited for the efficacy and safety evaluation of the EIB. Secondly, 40 patients were randomly assigned to receive either EIB or the bite-on-bite biopsy for comparison of the diagnostic yield, procedure time, and adverse event rate.

RESULTS

Combining two study stages, leiomyoma (74%) was diagnosed histologically to outnumber GIST (26%) with a diagnostic rate of 94% for patients receiving EIB. KIT exon 11 mutations (50%) and PDGFRA exon 12 mutations (16%) were detected in the small gastric GISTs. In the direct comparison, the diagnostic yield of EIB and the bite-on-bite biopsy was 85% and 50%, respectively (P = 0.018). There was no statistically significant difference of the mean procedure time or adverse event rate between these two groups.

CONCLUSIONS

Leiomyoma is more common than expected among these small tumors. Tissue diagnosis with an effective and safe sampling technique, such as EIB, is necessary for making further clinical decisions.

The Histopathological Types and Distribution Characteristics of Gastric Mixed Tumors

Objective

The present study aimed to investigate the histopathological types and distribution characteristics of gastric mixed tumors.

Methods

Detailed histological observations, together with related immunohistochemical and genetic tests, were analyzed on 960 surgically resected samples in 6 hospitals with gastric mixed tumors from May 2017 to May 2021 in this retrospective study.

Results

Epithelial-derived tumors accounted for 80.10% (769/960) of the gastric mixed tumor samples studied, and tumors of different tissue origins accounting for 10.83% (104/960), mesenchymal-derived tumors accounting for 6.25% (60/960), neuroendocrine tumors accounting for 2.40% (23/960), and lymphoma accounting for 0.42% (4/960). The histological types of gastric mixed tumors identified as most commonly were epithelial originated, followed by mixed tumors of different tissue originated, then mixed neuroendocrine, lymphoma, and mesenchymal originated in sequence. The histological number of gastric mixed tumors was ≤ 3 in 83.23% (799/960) of cases and > 4 in 16.77% (161/960) of cases. The mixed histological patterns of gastric mixed tumors were divided into three types: those with tumor cells interspersed with each other, those with incomplete fibrous tissue separation, and those without fibrous tissue separation. The gene target characteristics of gastric mixed tumors were the existence of multi-gene mutation, including human epidermalgrowth factor receptor-2 (HER2) gene amplification, key result areas (K-ras) and platelet-derived growth factor receptor alpha (PDGFRA).

Conclusion

Gastric mixed tumors should be adequately sampled, each piece of tissue should be involved in the morphological proportional division of the tumor, and any independent histological component should be written into the pathological examination report.

Natural History of Asymptomatic Esophageal Subepithelial Tumors of 30 mm or Less in Size

BACKGROUND

No definite guidelines for the management of small esophageal subepithelial tumors (SETs) have been established, because there are limited data and studies on their natural history. We aimed to assess the natural history and propose optimal management strategies for small esophageal SETs.

METHODS

Patients diagnosed as esophageal SETs ≤ 30 mm in size between 2003 and 2017 using endoscopic ultrasound (EUS) with a minimal follow-up of 3 months were enrolled, and their esophagogastroduodenoscopy (EGD) and EUS were retrospectively reviewed.

RESULTS

Of 275 esophageal SETs in 262 patients, the initial size was < 10 mm, 10-20 mm, and 20-30 mm in 104 (37.8%), 105 (38.2%), and 66 (24.0%) lesions, respectively. Only 22 (8.0%) SETs showed significant changes in size and/or echogenicity and/or morphology at a median of 40 months (range, 4-120 months). Tissues of 6 SETs showing interval changes were obtained using EUS-guided fine needle aspiration biopsy; 1 was identified as a gastrointestinal stromal tumor (GIST) and was surgically resected, while the other 5 were leiomyomas and were regularly observed. Eight SETs showing interval changes were resected surgically or endoscopically without pathological confirmation; 1 was a GIST, 2 were granular cell tumors, and the other 5 were leiomyomas.

CONCLUSION

Regular follow-up with EGD or EUS may be necessary for esophageal SETs ≤ 30 mm in size considering that small portion of them has a possibility of malignant potential. When esophageal SETs ≤ 30 mm show significant interval changes, pathological confirmation may precede treatment to avoid unnecessary resection.

The necessarity of treatment for small gastric subepithelial tumors (1-2 cm) originating from muscularis propria: an analysis of 972 tumors

Background and objectives

Up till now, there are still controversies about the specific indication of endoscopic resection for small gastric subepithelial tumors (gSETs) originating from muscularis propria. We aimed to investigate the safety of endoscopic resection and postoperative pathology analysis.

Method

The patients with primary small gSETs originating from muscularis propria, treated by endoscopic resection in the endoscopic center of Shengjing Hospital between January, 2011 and September, 2019 were enrolled. The complete resection rate, adverse events and clinicopathological features were recorded.

Result

A total of 936 patients with 972 gastric SETs ≤ 2 cm originating from muscularis propria were included in our study. All the lesions were successfully treated by endoscopic resection. Nearly half of lesions were proved to be gastrointestinal stromal tumor (GIST) [n = 411 (42.3%)] according to postoperative pathology. All the objects were further subdivided into 2 groups, ≤ 1 cm, > 1 and ≤ 2 cm gSETs. The risk of gastric GIST of intermediate/high risk in the group (> 1 and ≤ 2 cm gSETs) is 8.41 times as that of gastric GIST in the group (the size of gastric ≤ 1 cm gSETs) (P < 0.05).

Conclusion

Endoscopic resection is a safe and effective treatment for small gSETs. gSETs (1–2 cm) is more risky than gSETs (≤ 1 cm) and should be resected. This should be evaluated by further studies.

How to Approach Submucosal Lesions in the Gastrointestinal Tract: Different Ideas between China and USA

Between 2019 and 2020, the author Gao pursued advanced endoscopic training at the University of Mississippi Medical Center in the USA. She experienced certain different ideas between the East (China) and the West (USA) in terms of endoscopic approach to the submucosal tumors (SMTs) or lesions in the gastrointestinal (GI) tract. In the West (USA), when SMTs are found on gastroscopy, the main goal of endoscopists is to obtain a tissue diagnosis through endoscopic ultrasound-guided fine-needle aspiration or biopsy (EUS-FNA or FNB) or single incision needle-knife biopsy (SINK); if immunohistochemical tests confirmed the GISTs, the first-line treatment is local surgery, that is, diagnosis before treatment, whereas in China, SMTs will be completely resected with endoscopic technology for those with no lymph node metastasis or extremely low risk of lymph node metastasis. There may not be pathological tissue at first, that is, treatment before diagnosis.

Efficacy of the Franseen needle for diagnosing gastrointestinal submucosal lesions including small tumors

Background and Objectives:

Several studies have demonstrated that EUS-guided fine-needle biopsy (EUS-FNB) is useful for diagnosing gastrointestinal subepithelial lesions (GI SELs). However, there is limited evidence regarding the use of Franseen needles during EUS-FNB for patients with GI SELs. In addition, the optimal approach for diagnosing small SELs is unclear. This study aimed to evaluate whether EUS-FNB using a Franseen needle was effective for diagnosing GI SELs, including small lesions.

Methods:

Between January 2013 and January 2020, 150 consecutive patients with GI SELs underwent EUS-FNA/FNB to achieve a histological diagnosis. Eighty-six consecutive patients who underwent EUS-FNB using a Franseen needle were compared to 64 patients who underwent EUS-FNA using a conventional needle.

Results:

The diagnostic yield was significantly higher using a Franseen needle than using a conventional needle (85% vs. 75%, P = 0.006). Furthermore, in cases with SELs that were <20 mm, the diagnostic yield was significantly higher using a Franseen needle than using a conventional needle (81% vs. 45%; P = 0.003). Multivariate analysis revealed that obtaining a sufficient diagnostic sample was independently predicted by Franseen needle use (adjusted odds ratio: 2.8, 95% confidence interval: 1.2–6.3; P = 0.01) and tumor size of >20 mm (adjusted odds ratio: 3.4, 95% confidence interval: 1.4–8.2; P = 0.006).

Conclusion:

Even when attempting to diagnose small GI SELs, EUS-FNB using a Franseen needle appears to provide a more efficient acquisition of true histological core tissue than using a conventional needle.

The Pathologic Confirmation in Subepithelial Tumors

Background/Aims: Subepithelial tumors (SETs) are small, mostly asymptomatic lesions with normal overlying mucosa, usually identified incidentally on endoscopy. The aim of this study was to evaluate the pathologic diagnosis of SETs, and to assess the diagnostic yield and impact of endoscopic submucosal dissection (ESD) biopsy on the management of patients with SETs.Materials and Methods: We included 52 subepithelial lesions in this study during the study period. Inclusion criteria included size of the SET >2 cm, and a gastrointestinal stromal tumor (GIST) that cannot be excluded using EUS. We performed an endoscopic biopsy of each SET using the ESD technique.Results: The mean diameter of the lesions was 24.15±6.0 mm. The diagnostic yield of this method was 96.15%. Among the 52 participants, 45 were located in the stomach, four in the esophagus, and three in the duodenum. The pathologic diagnoses included: 17 leiomyomas, 13 GISTs, 11 ectopic pancreases, two carcinomas, two inflammatory fibroid polyps, two Brunner’s gland hyperplasia, two lipomas, one glomus tumor, and two remained undiagnosed. The mean duration of the procedure was 13.44±2.41 minutes. Three complications were associated with the procedure.Conclusions: Deep biopsy via ESD is useful in determining the histopathologic nature of SETs. This method minimizes the need for unnecessary surgery in benign SETs.

Endoscopic Resection of Gastrointestinal Stromal Tumor: Is It Safe?

Recently, results from clinical studies of endoscopic resection of gastrointestinal stromal tumor (GIST) in the stomach are being reported. This procedure has several advantages, such as the provision of a definite diagnosis and therapeutic plan, avoidance of frequent follow-up examination, and reduction of patients’ anxiety. However, several concerns also exist such as a limited number of studies, low R0 resection rate, and relatively shorter follow-up period compared with surgical resection. Nevertheless, it is encouraging that most of the post-procedural complications have been treated with conservative management and that some of the patients did not show recurrence of the tumor during long-term follow-up. The selection of suitable cases and the experience of the endoscopists are the most important factors for successful endoscopic resection of gastric GIST. Development of novel procedures as well as collaboration with laparoscopic surgeons are currently in progress.

Optimal number of needle punctures in endoscopic ultrasound-guided fine-needle biopsy for gastric subepithelial lesions without rapid on-site evaluation

PURPOSE

The utility of endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) for gastric subepithelial lesions (SELs) has been reported. In this study, we examined the optimal number of needle punctures during EUS-FNB for gastric SELs without rapid on-site evaluation (ROSE). The factors that allowed for a single needle puncture to arrive at the correct diagnosis were also analyzed.

METHODS

We conducted a retrospective study of all patients who underwent EUS-FNB to evaluate gastric SELs between April 2015 and September 2020; 51 patients with 57 gastric SELs were enrolled. The optimal number of needle punctures was determined when additional needle passes did not increase diagnostic sensitivity by more than 10%. Factors allowing for only a single needle puncture to arrive at the correct diagnosis were identified by univariate and multivariate logistic regression analyses.

RESULTS

EUS-FNB resulted in a definitive final diagnosis in 48 of 57 lesions (84%). Lesions in the gastric body (odds ratio [OR] 6.15, 95% confidence interval [CI] 1.75-21.6; P < 0.01) and lesions punctured using a 22G Franseen needle (OR 3.61, 95% CI 1.07-12.3; P = 0.04) were independent factors that allowed for only a single needle puncture to arrive at the correct diagnosis. The optimal number of needle punctures for lesions using a 22G Franseen needle in the gastric body and other lesions was two and three, respectively.

CONCLUSION

The optimal number of needle punctures in EUS-FNB for gastric SELs without ROSE was two or three, depending on the location and type of needle used.

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.

Tunneled biopsy is an underutilised, simple, safe and efficient method for tissue acquisition from subepithelial tumours

BACKGROUND

Tissue acquisition from subepithelial lesions is often attempted by endoscopic ultrasound (EUS)-sampling as conventional endoscopic biopsy usually fails to reach deeper layers of the gastrointestinal wall.

AIM

To investigate the utilisation, safety and diagnostic yield of an intensified “bite-on-bite” tunnel biopsy technique.

METHODS

In this retrospective cohort study, all patients presenting with subepithelial masses in the upper gastrointestinal tract from March 2013 to July 2019 were included. Data were analysed for size and location of the subepithelial mass, use of intensified tunnel biopsy protocol (more than 10 double bite-on-bite biopsies) or superficial conventional biopsies, histology and imaging results, occurrence of readmission and adverse events after endoscopy.

RESULTS

Two hundred and twenty-nine patients with subepithelial lesions were included. Superficial conventional biopsies were taken in 117 patients and were diagnostic only in one lipoma (0.9 %). Tunnel biopsies taken in 112/229 (48.9%) patients were significantly more likely to provide histological diagnosis (53.6%; P < 0.001). For lesions ≥ 10mm the diagnostic yield of tunnel biopsies further increased to 41/67 (61.2%). No immediate or delayed complications were reported. Only 8 of the 51 endoscopists (15.7%) regularly attempted tunnel biopsies.

CONCLUSION

Tunnel biopsy is a simple, safe and efficient but underutilised diagnostic modality for tissue acquisition in subepithelial masses. It should be routinely attempted at the initial endoscopy.

Diagnostic yields of endoscopic ultrasound-guided fine-needle tissue acquisition according to the gastric location

The diagnostic accuracy of endoscopic ultrasound-guided fine-needle tissue acquisition (EUS-FNTA) according to the gastric location of subepithelial tumors (SETs) has not been well established. We aimed to evaluate the efficacy of EUS-FNTA for the diagnosis of gastric SETs according to tumor location.Thirty-three patients diagnosed with gastric SETs via EUS-FNTA from January 2016 to May 2018 were analyzed retrospectively. Patient demographics, diagnostic yields, and complications were evaluated.Nineteen patients (57.6%) were female, with a mean age of 57.7 years. Endoscopic ultrasound revealed a mean longitudinal diameter of 25.6 mm. The most common location of SETs was in the gastric body (n = 18, 54.5%), followed by cardia and fundus (n = 10, 30.3%), and antrum (n = 5, 15.2%). A 20-gauge biopsy needle was most frequently used (90.9%). The diagnostic yield was obtained in 23 patients (69.7%). The most common diagnosis was gastrointestinal stromal tumor (73.9%), followed by leiomyoma (17.4%). The diagnostic yield of SETs in gastric antrum (0/5, 0%) was significantly lower than that in the gastric body and cardia (23/28, 82.1%, P = .001). A case of immediate bleeding after EUS-FNTA occurred in 1 patient (3.0%) who recovered uneventfully. According to related literature, the overall diagnostic yield of SETs in gastric antrum was significantly lower than that in the gastric body, fundus, and cardia (29.7% vs 71.4%, P < .001, n = 191).EUS-FNTA is ineffective in the diagnosis of SETs in the gastric antrum. Although EUS-FNTA is an advanced diagnostic tool for gastric SETs, it is essential to develop more effective methods for the diagnosis of antral SETs.

What About Gastric Schwannoma? A Review Article

PURPOSE

Gastric schwannomas (GSs) are rare mesenchymal neoplasms of the gastrointestinal tract. Diagnosis is often achieved postoperatively, based on pathology reports of retrieved specimens. The aim of the present study is to follow up all patients with gastric schwannoma (Gs) undergoing endoscopic, partial, or more extended surgery and to evaluate the appearance of local or distant recurrence.

METHODS

A PubMed, Cochrane, and Embase systematic review of the literature has been performed. Original papers, review articles, and case reports published between 1988 and 2019 were considered eligible. All the studies who met the inclusion criteria were analyzed. Statistical analysis of data has been performed using GraphPad Prism 7 software.

RESULTS

Three hundred twenty-eight articles were found, and a total of 102 were included and analyzed in depth. Fifty-three papers reported the follow-up information, ranging from 1 to 417 months across different studies. Among them, 31 patients underwent endoscopic removal of the gastric lesions; 140 patients underwent local surgery, including wedge resection or partial gastrectomy; and 148 patients underwent subtotal or total gastrectomy. The median follow-up was of 27-38-33 months, respectively. No recurrence or distant metastasis was detected in the endoscopy group. Among local surgery group, liver metastasis was reported in one case; in extended surgery group, one patient died for multiple liver metastases.

CONCLUSIONS

Local or more extended surgery involved a larger cohort of patients and reported satisfactory long-term results compared with endoscopy group. Surgery in absence of a definite preoperative diagnosis is considered the gold standard treatment for resectable Gs.

Differential diagnosis for esophageal protruded lesions using a deep convolution neural network in endoscopic images

BACKGROUND AND AIMS

Recent advances in deep convolutional neural networks (CNNs) have led to remarkable results in digestive endoscopy. In this study, we aimed to develop CNN-based models for the differential diagnosis of benign esophageal protruded lesions using endoscopic images acquired during real clinical settings.

METHODS

We retrospectively reviewed the images from 1217 patients who underwent white-light endoscopy (WLE) and EUS between January 2015 and April 2020. Three deep CNN models were developed to accomplish the following tasks: (1) identification of esophageal benign lesions from healthy controls using WLE images; (2) differentiation of 3 subtypes of esophageal protruded lesions (including esophageal leiomyoma [EL], esophageal cyst (EC], and esophageal papilloma [EP]) using WLE images; and (3) discrimination between EL and EC using EUS images. Six endoscopists blinded to the patients' clinical status were enrolled to interpret all images independently. Their diagnostic performances were evaluated and compared with the CNN models using the area under the receiver operating characteristic curve (AUC).

RESULTS

For task 1, the CNN model achieved an AUC of 0.751 (95% confidence interval [CI], 0.652-0.850) in identifying benign esophageal lesions. For task 2, the proposed model using WLE images for differentiation of esophageal protruded lesions achieved an AUC of 0.907 (95% CI, 0.835-0.979), 0.897 (95% CI, 0.841-0.953), and 0.868 (95% CI, 0.769-0.968) for EP, EL, and EC, respectively. The CNN model achieved equivalent or higher identification accuracy for EL and EC compared with skilled endoscopists. In the task of discriminating EL from EC (task 3), the proposed CNN model had AUC values of 0.739 (EL, 95% CI, 0.600-0.878) and 0.724 (EC, 95% CI, 0.567-0.881), which outperformed seniors and novices. Attempts to combine the CNN and endoscopist predictions led to significantly improved diagnostic accuracy compared with endoscopists interpretations alone.

CONCLUSIONS

Our team established CNN-based methodologies to recognize benign esophageal protruded lesions using routinely obtained WLE and EUS images. Preliminary results combining the results from the models and the endoscopists underscored the potential of ensemble models for improved differentiation of lesions in real endoscopic settings.

Spindle cell neoplasms of the upper gastrointestinal tract, hepatobiliary tract, and pancreas by fine needle aspiration: A single institutional experience of 15 years with follow-up data

BACKGROUND

The diagnosis of spindle cell neoplasms (SCN) of the upper gastrointestinal (GI) tract, hepatobiliary tract, and pancreas detected by fine needle aspiration (FNA) is challenging. We describe a single-center experience of these samples with follow-up data and characterization of the morphologic findings.

METHODS

We retrospectively reviewed pathology records for all FNAs diagnostic for or suggestive of SCN on esophagus, stomach, small bowel, liver, and pancreas in a 15 year period. All cases with at least 6 month follow-up were included. Surgical material (biopsy or resection) was the diagnostic gold standard. All FNAs with subsequent surgical specimens were reviewed and assessed for cellularity, architectural features, and nuclear features.

RESULTS

In 15 years, 5101 FNAs of the upper GI tract, hepatobiliary tract, and pancreas were performed. SCN was diagnosed in 98 (2%) patients. Seventy-two patients had definitive pathologic diagnoses: 68 were neoplastic and four were non-neoplastic. Cytomorphologic review in relationship to final diagnosis revealed three statistically significant features: low cellularity favors a benign process (P = .00544), epithelioid nuclear morphology favors malignancy (P = .00278), and identification of perinuclear vacuoles favors a diagnosis of GIST over non-GIST SCN (P = .04236).

CONCLUSIONS

Among cases with follow-up, final pathologic diagnoses were SCN in 94% of cases diagnosed as SCN on FNA of upper GI, hepatobiliary tract, and pancreas. Although some cytomorphologic criteria are more suggestive of malignancy, arriving at a specific diagnosis relies on collaboration of clinical, radiologic, cytomorphologic, and immunohistochemical data.

Outcomes of endoscopic ultrasound and endoscopic resection of gastrointestinal subepithelial lesions: a single-center retrospective cohort study

Background

Endoscopic resection (ER) is an emerging therapeutic alternative for subepithelial gastrointestinal lesions (SELs). We aimed to determine whether size, layer of origin, and histology based on endoscopic ultrasound (EUS) and EUS-guided sampling (EUS-GS) influenced the outcomes and selection of patients for ER.

Methods

We performed a retrospective review of patients who underwent EUS, EUS-GS and resection of SELs from 2012-2019. Two pathologists reviewed the histology and layer of origin of all resected specimens, serving as the criterion for EUS accuracy.

Results

Seventy-three patients were included, of whom 59 (81%) were gastric SELs. Per EUS, median lesion size was 21 mm (interquartile range 15-32), and 63 (86%) originated from the 4th layer. The overall accuracy of EUS and EUS-GS in predicting the layer of origin and histology was 88% (95% confidence interval [CI] 77-94%) and 96% (95%CI 87-98%), respectively. Based on EUS, 18 (25%) patients were referred for ER, 5 (7%) to laparoscopic-endoscopic cooperative surgery, and 50 (68%) to surgery. Size >20 mm was associated with the type of resection approach (P=0.005), while layer of origin and histology were not (P=0.06 and P=0.09, respectively). When SELs were inaccurately classified (n=4) there were no adverse events or revision of the resection approach.

Conclusions

EUS plays an important role in the outcome of resection approach for SELs, with size significantly influencing the selection for ER. In patients undergoing ER, no revised resections were needed when EUS was inaccurate.

Diagnosis of Pancreatic Solid Lesions, Subepithelial Lesions, and Lymph Nodes Using Endoscopic Ultrasound

Currently, endoscopic ultrasound (EUS) has become widely accepted and has considerable advantages over computed tomography (CT) and other imaging modalities, given that it enables echostructure assessment in lesions with <1 cm diameter and permits high resolution imaging. EUS-guided tissue acquisition (EUS-TA) provides consistent results under ultrasound guidance and has been considered more effective compared to CT- or ultrasound-guided lesion biopsy. Moreover, complication rates, including pancreatitis and bleeding, have been extremely low, with <1% morbidity and mortality rates, thereby suggesting the exceptional overall safety of EUS-TA. The aggressive use of EUS for various lesions has been key in facilitating early diagnosis and therapy. This review summarizes the diagnostic ability of EUS for pancreatic solid lesions, subepithelial lesions, and lymph nodes where it is mainly used. EUS has played an important role in diagnosing these lesions and planning treatment strategies. Future developments in EUS imaging technology, such as producing images close to histopathological findings, are expected to further improve its diagnostic ability. Moreover, tissue acquisition via EUS is expected to be used for precision medicine, which facilitates the selection of an appropriate therapeutic agent by increasing the amount of tissue collected and improving genetic analysis.

Current status of newer generation endoscopic ultrasound core needles in the diagnostic evaluation of gastrointestinal lesions

Endoscopic ultrasound-guided tissue acquisition is now an imperative technique for the diagnosis of multiple diseases in the gastrointestinal tract and nearby structures. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) and fine needle biopsy via dedicated FNB needles (EUS-FNB) are two standard-essential tools for tissue acquisition. The choice of needle type is an important factor determining appropriate tissue acquisition. Multiple studies have compared EUS-FNA versus EUS-FNB on different lesions also there are several studies evaluated different needles in terms of sampling adequacy and cytological and histological accuracy. Prior studies comparing prior-generation FNB needles to FNA did not show an increased diagnostic yield with FNB. However, the newer-generation needles have demonstrated enhanced performance compared with their predecessors. As they may provide a large amount of tissue for the cytological and histological evaluation, rapid onsite specimen evaluation (ROSE), and immunohistochemical and molecular analyses, which may be very important for targeted therapy. In this review, we discuss current evidence and literature on the use of the newer generation needles for pancreatic and non-pancreatic lesions.

EUS-guided fine-needle biopsy sampling versus FNA in the diagnosis of subepithelial lesions: a large multicenter study

BACKGROUND AND AIMS

Although conventional EUS-guided FNA (EUS-FNA) has previously been considered first-line for sampling subepithelial lesions (SELs), variable accuracy has resulted in increased use of fine-needle biopsy (FNB) sampling to improve diagnostic yield. The primary aim of this study was to compare FNA versus FNB sampling for the diagnosis of SELs.

METHODS

This was a multicenter, retrospective study to evaluate the outcomes of EUS-FNA and EUS-guided FNB sampling (EUS-FNB) of SELs over a 3-year period. Demographics, lesion characteristics, sensitivity, specificity, accuracy, number of needle passes, diagnostic adequacy of rapid on-site evaluation (ROSE), cell block accuracy, and adverse events were analyzed. Subgroup analyses were performed comparing FNA versus FNB sampling by location and diagnostic yield with or without ROSE. Multivariable logistic regression was also performed.

RESULTS

Two hundred twenty-nine patients with SELs (115 FNA and 114 FNB sampling) underwent EUS-guided sampling. Mean patient age was 60.86 ± 12.84 years. Most lesions were gastric in location (75.55%) and from the fourth layer (71.18%). Cell block for FNB sampling required fewer passes to achieve conclusive diagnosis (2.94 ± 1.09 vs 3.55 ± 1.55; P = .003). The number of passes was not different for ROSE adequacy (P = .167). Immunohistochemistry was more able to be successfully performed in more FNB sampling samples (69.30% vs 40.00%; P < .001). Overall, sensitivity and accuracy were superior for FNB sampling versus FNA (79.41% vs 51.92% [P = .001] and 88.03% vs 77.19% [P = .030], respectively). On subgroup analysis, sensitivity and accuracy of FNB sampling alone was superior to FNA + ROSE (79.03% vs 46.67% [P = .001] and 87.25% vs 68.00% [P = .024], respectively). There was no significant difference in diagnostic yield of FNB sampling alone versus FNB sampling + ROSE (P > .05). Multivariate analysis showed no predictors associated with accuracy. One minor adverse event was reported in the FNA group.

CONCLUSIONS

EUS-FNB was superior to EUS-FNA in the diagnosis of SELs. EUS-FNB was also superior to EUS-FNA alone and EUS-FNA + ROSE. These results suggest EUS-FNB should be considered a first-line modality and may suggest a reduced role for ROSE in the diagnosis of SELs. However, a large randomized controlled trial is required to confirm our findings.

Signet Ring Cell Carcinoma Mimicking Gastric Gastrointestinal Stromal Tumor: A Case Report

The presentation of submucosal gastric cancer, especially signet ring cell carcinoma, is rare. The submucosal tumor (SMT) is covered with normal mucosa, and confirmation is difficult through endoscopic biopsy; thus, histologic diagnosis is important to determine the appropriate treatment method. Here, we report a case of gastric signet ring cell carcinoma mimicking gastrointestinal stromal tumor (GIST). A 2-cm-sized SMT suspected of being a GIST on preoperative endoscopic ultrasonography and computed tomography was suspected to be cancerous during surgery. The frozen diagnosis of the resected mass (obtained via wedge resection) showed a carcinoma with signet ring feature, and additional frozen diagnosis of one enlarged lymph node revealed metastatic cancer. Therefore, subtotal gastrectomy with lymph node dissection was performed. This case report suggests that preoperative histologic diagnosis of high-risk SMT might be useful, although the tumor had typical features of GIST on preoperative imaging. Overall, if a tumor is suspected of being a gastric carcinoma during surgery and the differential diagnosis between gastric carcinoma and GIST is uncertain, a careful surgical approach should be considered to account for the possibility of adenocarcinoma.

Endoscopic ultrasound-guided needle-based confocal laser endomicroscopy in gastrointestinal subepithelial lesions: Feasibility study

BACKGROUND AND AIM

Needle-based confocal laser endomicroscopy (nCLE) allows for real-time optical biopsies during endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). Little is known about nCLE imaging of gastrointestinal subepithelial lesions (GI-SEL); therefore, we determined its feasibility.

METHODS

We carried out EUS, nCLE, and finally FNA in 25 patients with GI-SEL between November 2015 and December 2018. We retrospectively compared nCLE findings with pathological findings of EUS-FNA or surgical specimens. For concordance analysis, two endoscopists independently validated representative nCLE images 5 months or more after examinations.

RESULTS

Adequate sample acquisition rate of EUS-FNA was 67% per needle pass and 96% per patient. EUS-FNA was diagnostic in 80% (20/25), suspicious in 4% (1/25), and nondiagnostic in 16% (4/25). nCLE image acquisition rate was 100% and its concordance rate with final pathology was 88% (22/25), which was not significantly different from diagnostic and suspicious EUS-FNA. nCLE could differentiate GI stromal tumors (GISTs) from leiomyoma, in that GISTs were characterized by contrast-enhanced densely populated spindle cell tumors with unenhanced rod-shaped nuclei in 93% of 14 patients, whereas leiomyomas were characterized by narrower spindle cell tumors with fewer and smaller unenhanced nuclei in 100% of three patients. In rectal metastasis from lung adenocarcinoma, some pleomorphic dark nests were observed. At concordance analysis between the two endoscopists' validation results, κ value was 0.560 (P < 0.001), indicating moderate agreement. There were no adverse events associated with nCLE and EUS-FNA.

CONCLUSION

Needle-based confocal laser endomicroscopy can be safe and useful for on-site detection of abnormalities of GI-SEL (UMIN 000013857).

Third Space Endoscopy: Lessons Learnt From a Decade of Submucosal Endoscopy

The field of third space endoscopy (TSE), also called submucosal endoscopy using a mucosal flap valve, allows secure access to the submucosal and deeper layers of the gastrointestinal tract without the risk of a full-thickness perforation. Since the first description of per-oral endoscopic myotomy (POEM) for the treatment of achalasia cardia 10 years ago, this field has expanded rapidly. Several new procedures, submucosal tunneling endoscopic resection, gastric-POEM, Zenker POEM, per-rectal endoscopic myotomy, diverticular POEM, and recanalization for complete esophageal obstruction (per-oral endoscopic tunneling for restoration of the esophagus), have been performed. All TSE procedures employ a similar technique-after a mucosal incision, a submucosal tunnel is created, a myotomy is performed, or a subepithelial tumor is resected distal to the site of mucosal incision, after which the mucosal incision is closed. Potential indications for TSE include resection of subepithelial tumors in the esophagus, gastroesophageal junction, or stomach; refractory gastroparesis; Zenker diverticulum; Hirschsprung disease or other forms of megacolon; and recanalization for complete esophageal obstruction. Data are currently available for POEM, submucosal tunneling endoscopic resection, and gastric-POEM, although mainly in the form of retrospective studies, and randomized trials and long-term follow-up data are limited. Submucosal endoscopy has an excellent safety profile with very few intraoperative adverse events, the majority being related to insufflation, although bleeding, perforation, and sepsis have been reported. TSE procedures require special training and have demonstrated a learning curve.

Snare-assisted endoscopic resection of gastric subepithelial tumors originating from the muscularis propria layer: a multicenter study

BACKGROUND AND AIM

Although successful endoscopic resection of gastric subepithelial tumors (SETs) originating from the muscularis propria (MP) layer has been frequently reported, it requires a relatively complicated technique and has a high perforation rate. In this retrospective study, we evaluated the efficacy and safety of the snare-assisted endoscopic resection (SAER) method which is performed using a snare and insulated-tip (IT) knife via a single-channel endoscope to reduce the perforation rate.

METHODS

In this study, fifty-six patients with gastric SETs originating from the MP layer treated by the SAER method at three institutions between July 2017 and December 2017 were reviewed. The procedure involved multiple steps as shown in Fig. 2. Data were obtained on demographics, SET features, histopathological diagnoses, procedure time, en bloc resection rate, R0 resection (negative margins) status, and adverse events.

RESULTS

Endoscopic resection was successfully performed in all patients. The median overall procedure time was 43.5 min (range 26-106 min). The mean size of resected specimens was 19.73 mm (range 10-33 mm). The overall rate of en bloc resection was 96.4% (54/56). In addition, the perforation rate was 7.1% (4/56), and defects in the stomach wall were very small and easily closed using metallic clips. No postprocedural bleeding occurred in any case.

CONCLUSIONS

The SAER method is an effective, safe, less costly technique for the removal of some gastric SETs originating from the MP layer with an appropriate size.

Sigmoid endometriosis diagnosed preoperatively using endoscopic ultrasound-guided fine-needle aspiration

We report a case of sigmoid endometriosis diagnosed preoperatively based on endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) findings. A 42-year-old female came to us with left lower abdominal pain and bloating that had started 3 months prior. CT and MRI results showed wall thickening of the sigmoid colon. A colonoscopy procedure could not be completed because passage through the sigmoid colon was blocked due to severe stenosis, while mucosal biopsy samples obtained during that procedure could not confirm a diagnosis. EUS-FNA was then performed and specimens were obtained from the muscular layer with stenosis, which revealed a thickened hypoechoic lesion. Histological findings obtained by use of EUS-FNA demonstrated a large amount of fibrosis in endometrial glands and a diagnosis of sigmoid endometriosis was confirmed by additional immunostaining. Thus, a laparoscopic sigmoidectomy was performed, with sigmoid endometriosis finally diagnosed. Confirmation of a diagnosis of intestinal endometriosis based on histological findings of mucosal biopsy specimens obtained by colonoscopy is difficult, because endometrial implants are primarily located in the serosal and/or muscular layer. When safe aspiration is possible, we consider that EUS-FNA can be an effective method for preoperative diagnosis of intestinal endometriosis, which may contribute to avoidance of unnecessary or excessive surgery.

Endoscopic Ultrasound-Guided Fine Needle Aspiration and Biopsy in Gastrointestinal Subepithelial Tumors

The incidence of asymptomatic and incidentally found upper gastrointestinal subepithelial tumors (SETs) is increasing with the implementation of national cancer screening and the development of high-resolution endoscopy in Korea. However, endoscopy alone cannot be used to determine whether SETs are benign or malignant. Endoscopic ultrasound (EUS) is used to further characterize these lesions through the examination of their layered structure, internal echogenicity, size, and relationship to the extramural structure. These provide additional information on whether the lesion is benign or malignant. Nevertheless, the sensitivity and specificity of EUS alone in predicting malignancy is unsatisfactory. Recent guidelines have recommended deciding the timing of EUS-fine needle aspiration and biopsy (EUS-FNA/B) for SETs based on tumor size, malignant features on endoscopy, and high-risk features on EUS. The diagnostic accuracy of EUS-FNA/B is reportedly influenced by factors including needle size, number of needle passes, use of suction, use of a stylet in the needle assembly, fanning technique, availability of an on-site cytopathologist, and experience of the endosonographer. Therefore, according to the characteristics of the SETs, various subsequent methods and techniques should be appropriately employed to improve the diagnostic yield of EUS-FNA/B.

Fine-needle biopsy is superior to fine-needle aspiration of suspected gastrointestinal stromal tumors: a large multicenter study

Background and study aims  There are numerous studies published on the diagnostic yield of the new fine-needle biopsy (FNB) needles in pancreas masses. However, there are limited studies in suspected gastrointestinal stromal tumors (GIST lesions). The aim of this study was to evaluate the diagnostic yield of a new fork-tip FNB needle. Patients and methods  This was a multicenter retrospective study of consecutive patients from prospectively maintained databases comparing endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) versus endoscopic ultrasound-guided FNB (EUS-FNB) using the fork-tip needle. Outcomes measured were cytopathology yield (ability to obtain tissue for analysis of cytology), ability to analyze the tissue for immunohistochemistry (IHC yield), and diagnostic yield (ability to provide a definitive diagnosis). Results  A total of 147 patients were included in the study of which 101 underwent EUS-FNB and 46 patients underwent EUS-FNA. Median lesion size in each group was similar (21 mm vs 25 mm, P  = 0.25). Cytopathology yield, IHC yield, and diagnostic yield were 92 % vs 46 % ( P  = 0.001), 89 % vs 41 % ( P  = 0.001), and 89 % vs 37 % ( P  = 0.001) between the FNB and FNA groups, respectively. Median number of passes was the same between the two groups at 3.5. Conclusion  EUS-FNB is superior to EUS-FNA for diagnostic yield of suspected GIST lesions. This should be confirmed with a prospective study.

Noninvasive prediction model for diagnosing gastrointestinal stromal tumors using contrast-enhanced harmonic endoscopic ultrasound

BACKGROUND & AIMS

Subepithelial tumors (SETs) are difficult to diagnose accurately without invasive pathological confirmation. We created a noninvasive prediction model for diagnosing gastrointestinal stromal tumors (GISTs) using contrast-enhanced harmonic endoscopic ultrasound (CEH-EUS).

METHODS

We retrospectively reviewed 176 patients who underwent CEH-EUS from October 2011 to August 2017. Seventy patients with a diagnosis of GIST (n = 37) or leiomyoma (n = 33) were included. The long-to-short axis ratio (LSR) and enhancement patterns (vascularity, diffuse enhancement) on CEH-EUS were assessed. Logistic regression and classification and regression tree (CART) analyses were performed.

RESULTS

The mean age of all patients was 54.9 ± 13.68 years. The GIST group showed significantly higher rates of positive vascularity (81.1% vs. 15.2%, p < 0.001) and diffuse enhancement (51.4% vs. 15.2%, p = 0.001), and lower LSR (1.30 vs. 1.76, p < 0.001). In multivariate logistic regression, positive vascularity (odds ratio [OR] 27.765, 95% confidence interval [CI] 5.336-144.458) and low LSR (OR 18.940, 95% CI 3.623-99.007) were independent predictors of GIST. A noninvasive prediction model for GISTs was developed using the CART model, by allocating patients according to statistically significant variables.

CONCLUSIONS

The LSR and vascularity of SETs on CEH-EUS can be used as parameters for a noninvasive prediction model of GISTs. This model may be helpful in the early identification and treatment of GISTs.

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.

Advanced gastric cancer with features of a submucosal tumor diagnosed by endoscopic ultrasound-guided fine needle aspiration and boring biopsy preoperatively: A case report and literature review

•

Gastric carcinoma with features of a submucosal tumor is a rare condition.

•

Gastric carcinoma with features of a submucosal tumor has unique features.

•

Tissue sampling must be performed if gastric malignant submucosal tumor is suspected.

Introduction

Gastric cancer with features of a submucosal tumor (GCSMT) is rare, and the preoperative diagnosis is very difficult. We present a case of GCSMT diagnosed by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) and boring biopsy (deeper biopsy), successfully treated with distal gastrectomy and lymph node dissection.

Presentation of case

An 81-year-old man with a history of myocardial infarction and type 2 diabetes mellitus was admitted to our hospital for further examination of a gastric submucosal tumor. Endoscopic examination of the gastrointestinal tract showed a 30-mm submucosal tumor at the lower gastric body. Enhanced computed tomography revealed a tumor located at the lower body of the stomach and pyloric lymph node swelling. EUS-FNA and boring biopsy from the tumor revealed adenocarcinoma. Accordingly, distal gastrectomy with lymph node dissection was performed. Histopathological examination showed a poorly differentiated adenocarcinoma. Postoperative diagnosis was GCSMT with lymph node metastasis (T2, N1, M0, stage IIA).

Conclusion

We report a rare case of GCSMT with lymph node metastasis. Preoperative diagnosis of GCSMT is necessary to guide surgical management. EUS-FNA and boring biopsy could aid in obtaining adequate quantities of the specimens for histopathological and immunohistochemical diagnosis.

Submucosal tunneling endoscopic resection: An effective and safe therapy for upper gastrointestinal submucosal tumors originating from the muscularis propria layer

AIM

To evaluate the effectiveness and safety of submucosal tunneling endoscopic resection (STER) and compare its outcomes in esophageal and cardial submucosal tumors (SMTs) of the muscularis propria (MP) layer.

METHODS

From May 2012 to November 2017, 173 consecutive patients with upper gastrointestinal (GI) SMTs of the MP layer underwent STER. Overall, 165 patients were included, and 8 were excluded. The baseline characteristics of the patients and SMTs were recorded. The en bloc resection rate, complete resection rate, residual rate, and recurrence rate were calculated to evaluate the effectiveness of STER, and the complication rate was recorded to evaluate its safety. Effectiveness and safety outcomes were compared between esophageal and cardial SMTs.

RESULTS

One hundred and twelve men and 53 women with a mean age of 46.9 ± 10.8 years were included. The mean tumor size was 22.6 ± 13.6 mm. Eleven SMTs were located in the upper esophagus (6.7%), 49 in the middle esophagus (29.7%), 46 in the lower esophagus (27.9%), and 59 in the cardia (35.7%). Irregular lesions accounted for 48.5% of all lesions. STER achieved an en bloc resection rate of 78.7% (128/165) for GI SMTs with an overall complication rate of 21.2% (35/165). All complications resolved without intervention or were treated conservatively without the need for surgery. The en bloc resection rates of esophageal and cardial SMTs were 81.1% (86/106) and 72.1% (42/59), respectively (P = 0.142), and the complication rates were 19.8% (21/106) and 23.7% (14/59), respectively, (P = 0.555). The most common complications for esophageal SMTs were gas-related complications and fever, while mucosal injury was the most common for cardial SMTs.

CONCLUSION

STER is an effective and safe therapy for GI SMTs of the MP layer. Its effectiveness and safety are comparable between SMTs of the esophagus and cardia.

EUS-guided tissue sampling with a 20-gauge core biopsy needle for the characterization of gastrointestinal subepithelial lesions: A multicenter study

Background and Objective:

A new 20-gauge (G) biopsy needle with a core-trap technology has been developed with a large core size and enhanced flexibility. The aim of this multicenter study was to determine the feasibility, efficacy, and safety of EUS-guided fine-needle biopsy (EUS-FNB) with the new 20G needle in diagnosing subepithelial lesions (SELs).

Materials and Methods:

Retrospectively collected data from consecutive patients with SELs undergoing EUS-FNB with the 20G needle at five centers were analyzed.

Results:

A total of 50 SELs were included. The mean lesion size was 43.1 ± 17.5 mm. The lesion locations were esophagus (n = 1), stomach (n = 37), distal duodenum (n = 5), rectum (n = 6), and colon (n = 1). The procedure was technically feasible in all patients. Definitive diagnosis with full histological assessment including immunohistochemistry was obtained in 88% (44/50) of the patients. Considering malignant versus benign lesions, the sensitivity, specificity, positive predictive value, and negative predictive value were 85% (95% confidence interval [CI] 70.2–94.3), 100% (95% CI 58.7%–100%), 100% (95% CI 85.1%–100%), and 62.5 (95% CI 27.7–84.8), respectively. No major complications requiring additional care have been observed.

Conclusions:

In this multicenter study, we found that EUS-FNB with the new 20G core needle is an effective and safe method for the diagnosis of SELs with a high rate of producing adequate histological material and high diagnostic accuracy even from difficult-to-approach anatomical locations.

Characterization of subepithelial lesions of the stomach and esophagus by contrast-enhanced EUS: A retrospective study

Background and Objectives:

Subepithelial lesions (SELs) of the upper part of the digestive tract are rare, and it can be difficult to characterize them. Recently, contrast-enhanced endosonography (EUS) and elastometry have been reported as useful adjuncts to EUS and EUS-guided fine needle aspiration (EUS-FNA) in cases of pancreatic mass and lymph node involvement. The aim of this retrospective analysis was to evaluate whether contrast-enhanced EUS can discriminate benign submucosal lesions from malignant ones. We describe our retrospective experience using the contrast agent SonoVue^® (Bracco Imaging, Milan, Italy) in an attempt to increase the diagnostic yield.

Patients and Methods:

Between May 2011 and September 2014, 14 patients (5 men, 9 women; median age 64 years, range 31–80 years) with SELs of the stomach or esophagus underwent EUS with SonoVue^® (low mechanical index). There were 3 esophageal lesions and 11 gastric lesions. Mean size of the lesions was 30 mm (range 11–50 mm). They were discovered after anemia (n = 5), dysphagia (n = 1), and pain (n = 4) and during follow-up for resected gastrointestinal stromal tumors (GISTs) (n = 1) and a standard upper gastrointestinal endoscopy (n = 3). On endoscopic sonograms, 10 of these lesions were hypoechoic and located in the fourth layer (muscularis), and 4 were in the second or third layer (mucosa and submucosa). Contrast enhancement was assessed in the early phase (after several seconds) and late phase (>30 seconds); a final diagnosis was made based on the findings of EUS-FNA using a 19-gauge ProCore (Cook Medical, Bloomington, IN) (n = 9) or 22-gauge FNA system (Cook Medical) (n = 1), the resected specimen (n = 3), or deep biopsy (n = 1). Different immunostaining was used in the pathologic studies (RNA was analyzed later using the C-kit, CD-117, CD-34, desmin, DOG-1, α-smooth actin, caldesmon, PS-100, and Ki-67 antibodies).

Results:

Final diagnoses were leiomyoma (n = 4), GIST (n = 5), schwannoma (n = 1), inflammatory tumor of Helvig (n = 1), pancreas rest (n = 2), and fibrosis (n = 1). No complications occurred. All 5 GISTs showed enhancement in the early and late phases, whereas the 8 remaining lesions did not show any enhancement. Only 1 leiomyoma showed heterogeneous enhancement.

Limitations:

The monocentric and retrospective study design and small number of patients.

Conclusions:

In cases of SELs of the stomach or esophagus, SonoVue^® could be a complementary tool to endosonography to differentiate GISTs (early and clear enhancement) from other SELs (few or no enhancement), such as leiomyomas or pancreatic rest. These results are similar to those of the few, small studies published on this topic, but more studies with a larger number of patients are needed to confirm these findings.

Concise review on the comparative efficacy of endoscopic ultrasound-guided fine-needle aspiration vs core biopsy in pancreatic masses, upper and lower gastrointestinal submucosal tumors

Endoscopic ultrasound (EUS)-guided fine needle aspiration with or without biopsy (FNA/FNB) are the primary diagnostic tools for gastrointestinal submucosal tumors. EUS-guided fine needle aspiration (EUS-FNA) is considered a first line diagnostic method for the characterization of pancreatic and upper gastrointestinal lesions, since it allows for the direct visualization of the collection of specimens for cytopathologic analysis. EUS-FNA is most effective and accurate when immediate cytologic assessment is permitted by the presence of a cytopathologist on site. Unfortunately, the accuracy and thus the diagnostic yield of collected specimens suffer without this immediate analysis. Recently, a EUS-FNB needle capable of obtaining core samples (fine needle biopsy, FNB) has been developed and has shown promising results. This new tool adds a new dimension to the diagnostic and therapeutic utility of this technique. The aim of the present review is to compare the efficacy of EUS-FNA to that afforded by EUS-FNB in the characterization of pancreatic masses and of upper and lower gastrointestinal submucosal tumors.

A Novel Method of Diagnosing Aberrant Pancreas: Needle-based Confocal Laser Endomicroscopy

Aberrant pancreas is defined as pancreatic tissue present outside of the pancreas and is often found incidentally during esophagogastroduodenoscopy. Obtaining sufficient tissue to differentiate aberrant pancreas from other subepithelial lesions is sometimes difficult. Due to the lack of a definitive diagnosis, patients often undergo unnecessary surgery. We herein report the first case of aberrant pancreas in which the concomitant use of needle-based probe confocal laser endomicroscopy and fine-needle aspiration supported the final diagnosis. Needle-based probe confocal laser endomicroscopy provides a real-time in vivo histopathology evaluation and may be a feasible means of diagnosing aberrant pancreas.

Surgical treatment of gastrointestinal stromal tumors of the duodenum: a literature review

Background

Gastrointestinal stromal tumors (GIST) are the most frequent mesenchymal tumours in the digestive tract. The duodenal GIST (dGIST) is the rarest subtype, representing only 4-5% of all GIST, but up to 21% of the resected ones. The diagnostic and therapeutic management of dGIST may be difficult due to the rarity of this tumor, its anatomical location, and the clinical behavior that often mimic a variety of conditions; moreover, there is lack of consent for their treatment. This study has evaluated the scientific literature to provide consensus on the diagnosis of dGIST and to outline possible options for surgical treatment.

Methods

An extensive research has been carried out on the electronic databases MEDLINE, Scopus, EMBASE and Cochrane to identify all clinical trials that report an event or case series of dGIST.

Results

Eighty-six studies that met the inclusion criteria were identified with five hundred forty-nine patients with dGIST: twenty-seven patients were treated with pancreatoduodenectomy and ninety-six with only local resection (segmental/wedge resections); in four hundred twenty-six patients it is not possible identify the type of treatment performed (pancreatoduodenectomy or segmental/wedge resections).

Conclusions

dGISTs are a very rare subset of GISTs. They may be asymptomatic or may involve symptoms of upper GI bleeding and abdominal pain at presentation. Because of the misleading clinical presentation the differential diagnosis may be difficult. Tumours smaller than 2 cm have a low biological aggressiveness and can be followed annually by endoscopic ultrasound. The biggest ones should undergo radical surgical resection (R0). In dGIST there is no uniformly adopted surgical strategy because of the low incidence, lack of experience, and the complex anatomy of the duodenum. Therefore, individually tailored surgical approach is recommended. R0 resection with 1-2 cm clear margin is required. Lymph node dissection is not recommended due to the low incidence of lymphatic metastases. Tumor rupture should be avoided.

Diagnostic ability of a 22G Franseen needle in endoscopic ultrasound-guided fine needle aspiration of subepithelial lesions

The differential diagnosis of gastrointestinal subepithelial lesions (SELs) such as gastrointestinal stromal tumors from other benign tumors is important. In the present study, adequate sample rates of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) with a 22G Franseen needle for SELs were evaluated. The present study included 57 consecutive lesions (61 sessions) of EUS-FNA using a 22G needle to evaluate SELs between July 2013 and October 2017. Adequate sample rates were compared retrospectively between a 22G conventional needle group (C group) and a 22G Franseen needle group (F group). The overall adequate sample rate was 80.3%. The adequate sample rates in the C and F groups were 75.0% (33/44) and 94.1% (16/17), respectively (P=0.15). For lesions ≥20 mm, the adequate sample rates were 82.8% (24/29) in the C group and 91.7% (11/12) in the F group, 8.9% higher in the F group. However, for lesions <20 mm, the adequate sample rates were 60% (9/15) in the C group and 100% (5/5) in the F group, 40% higher in the F group (P=0.65, 0.26). In conclusion, the results of the present study suggested that using a 22G Franseen needle for EUS-FNA evaluation of SELs may improve adequate sample rates in small lesions <20 mm in diameter.

Gastrointestinal schwannomas: a rare but important differential diagnosis of mesenchymal tumors of gastrointestinal tract

BACKGROUND

Schwannomas of gastrointestinal tract are rare, mostly benign and notably different neoplasms from conventional schwannomas that arise in soft tissue or the central nervous system. These tumors are of clinical importance since they should always be considered in the differential diagnosis of submucosal lesions of gastrointestinal tract.

METHODS

Seven patients with a pathologically proven gastrointestinal schwannoma were identified in our series of mesenchymal tumors and reviewed retrospectively. Clinicopathological and immunohistochemical parameters along with the follow-up results were analysed.

RESULTS

The series included two males and five females, with a mean age 69 years (range, 39-81). Most patients were asymptomatic on presentation, except for two patients with abdominal pain. In the other cases (n = 5), the tumor was an incidental finding during other medical, imaging or surgical procedures. The tumors were located in the stomach (n = 4) and in the small intestine (n = 3) with an average size of 29 mm (range, 12-70). A preoperative diagnosis was achieved only in one case with a CT-guided core biopsy. Otherwise the clinical, intraoperative, endoscopic or radiological findings were unspecific. Patients with gastric tumor underwent either laparoscopic (n = 2) or open (n = 2) gastric wedge resection of the tumor; in the cases of intestinal tumor (n = 3) a segmentectomy was performed. Pathological examination revealed solid homogenous tumors, which were highly cellular and composed of spindle cells with positive staining for S100 protein, and confirmed the diagnosis of schwannoma. All tumors were negative for c-Kit, smooth muscle actin, desmin and DOG-1 and showed very low proliferation index. There were negative resection margins and no malignant variants were recognized. At an average follow-up of 60 months (range, 24-185) all patients were free of disease with no signs of recurrence or metastases and acceptable gastrointestinal function.

CONCLUSIONS

Schwannomas are rare, slow-growing and mostly asymptomatic gastrointestinal mesenchymal tumors. They are difficult to be diagnosed preoperatively as endoscopic and radiological findings are nonspecific but histological and immunohistochemical features are of paramount importance to differentiate between benign and malignant schwannomas, or other spindle cell sarcomas. The treatment of choice is complete surgical excision without a conclusive preoperative diagnosis, and the long-term outcome is excellent as these lesions are mostly benign.

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.