Endoscopic management of gastrointestinal stromal tumors

Novel classification of gastric polyps: The good, the bad and the ugly

Gastric polyps (GPs) are increasingly common. On upper endoscopy, they should be examined with white light and occasionally chromoendoscopy, and their morphology classified according to the Paris classification. Most GPs have a typical endoscopic appearance and can be associated with diseases like Helicobacter pylori infection. Histological examination is necessary for an accurate diagnosis. While most polyps are non-neoplastic and do not require treatment, some carry a risk of malignancy or are already malignant. Therefore, understanding the diagnosis, classification, and management of GPs is crucial for patient prognostication. Our new classification categorizes GPs into "good", "bad", and "ugly" based on their likelihood of becoming malignant. We aim to provide descriptions of the endoscopic appearance, pathology, treatment, and follow-up for different GPs, as well as clinical management flowcharts.

Use of Endoscopic Ultrasound Elastography to Differentiate between Gastrointestinal Stromal Tumor and Leiomyoma Localized in the Upper Gastrointestinal Tract

Background

Gastrointestinal stromal tumors (GISTs) have malignant potential. Distinction of GISTs from leiomyoma is important to the decision of follow-up or treatment for upper gastrointestinal tract subepithelial lesions (SELs). There are few studies on the evaluation of gastrointestinal SELs with endoscopic ultrasound (EUS) elastography.

Aims

To evaluate the efficiency of strain ratio (SR) measurement and Giovannini's classification (Gc) by EUS elastography in differentiating GISTs from leiomyomas.

Materials and methods

Twenty-three lesions with histopathological diagnoses of 13 GISTs and 10 leiomyomas were evaluated. The lesions' SR values were obtained from EUS reports retrospectively. Giovannini's classification was performed according to the elastography images recorded in the system. The effectiveness of SR and Gc in the distinction between GIST and leiomyomas was evaluated.

Results

Twelve of the GISTs and 3 of the leiomyomas were with scores 4 and 5 according to Gc (p = 0.006). Gastrointestinal stromal tumors had a higher SR than leiomyomas (p = 0.001). For the diagnosis of GISTs, sensitivity/specificity/diagnostic accuracy were 92.3%/80%/87% for SR alone, 92.3%/70%/82.6% for Gc alone, and 84.6%/80%/82.6% for the use of both SR and Gc.

Conclusions

This is the first study in which semi-quantitative (SR) and qualitative (Gc) methods were evaluated together for the distinction of GISTs and leiomyomas. The sensitivity of SR alone for diagnosing GIST is higher than that of Gc alone or the combination of both methods. Although SR alone does not diagnose GIST, it can be used as an auxiliary method in biopsy and follow-up decisions.

How to cite this article

Erdem RE, Bektaş M, Ellik ZM, et al. Use of Endoscopic Ultrasound Elastography to Differentiate between Gastrointestinal Stromal Tumor and Leiomyoma Localized in the Upper Gastrointestinal Tract. Euroasian J Hepato-Gastroenterol 2024;14(1):20-23.

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.

An artificial intelligence system for distinguishing between gastrointestinal stromal tumors and leiomyomas using endoscopic ultrasonography

BACKGROUND

Gastrointestinal stromal tumors (GISTs) and gastrointestinal leiomyomas (GILs) are the most common subepithelial lesions (SELs). All GISTs have malignant potential; however, GILs are considered benign. Current imaging cannot effectively distinguish GISTs from GILs. We aimed to develop an artificial intelligence (AI) system to differentiate these tumors using endoscopic ultrasonography (EUS).

METHODS

The AI system was based on EUS images of patients with histologically confirmed GISTs or GILs. Participants from four centers were collected to develop and retrospectively evaluate the AI-based system. The system was used when endosonographers considered SELs to be GISTs or GILs. It was then used in a multicenter prospective diagnostic test to clinically explore whether joint diagnoses by endosonographers and the AI system can distinguish between GISTs and GILs to improve the total diagnostic accuracy for SELs.

RESULTS

The AI system was developed using 10 439 EUS images from 752 participants with GISTs or GILs. In the prospective test, 132 participants were histologically diagnosed (36 GISTs, 44 GILs, and 52 other types of SELs) among 508 consecutive subjects. Through joint diagnoses, the total accuracy of endosonographers in diagnosing the 132 histologically confirmed participants increased from 69.7 % (95 % confidence interval [CI] 61.4 %-76.9 %) to 78.8 % (95 %CI 71.0 %-84.9 %; P = 0.01). The accuracy of endosonographers in diagnosing the 80 participants with GISTs or GILs increased from 73.8 % (95 %CI 63.1 %-82.2 %) to 88.8 % (95 %CI 79.8 %-94.2 %; P = 0.01).

CONCLUSIONS

We developed an AI-based EUS diagnostic system that can effectively distinguish GISTs from GILs and improve the diagnostic accuracy of SELs.

Use of Artificial Intelligence in the Prediction of Malignant Potential of Gastric Gastrointestinal Stromal Tumors

BACKGROUND AND AIMS

This study aimed to investigate whether AI via a deep learning algorithm using endoscopic ultrasonography (EUS) images could predict the malignant potential of gastric gastrointestinal stromal tumors (GISTs).

METHODS

A series of patients who underwent EUS before surgical resection for gastric GISTs were included. A total of 685 images of GISTs from 55 retrospectively included patients were used as the training data set for the AI system. Convolutional neural networks were constructed to build a deep learning model. After applying the synthetic minority oversampling technique, 70% of the generated images were used for AI training and 30% were used to test AI diagnoses. Next, validation was performed using 153 EUS images of 15 patients with GISTs. In addition, conventional EUS features of 55 patients in the training cohort were evaluated to predict the malignant potential of GISTs and mitotic index.

RESULTS

The overall sensitivity, specificity, and accuracy of the AI system for predicting malignancy risk were 83%, 94%, and 82% in the training dataset, and 75%, 73%, and 66% in the validation cohort, respectively. When patients were divided into low-risk and high-risk groups, sensitivity, specificity, and accuracy increased to 99% in the training dataset and 99.7%, 99.7%, and 99.6%, respectively, in the validation cohort. No conventional EUS features were found to be associated with either malignant potential or mitotic index (P > 0.05).

CONCLUSIONS

AI via a deep learning algorithm using EUS images could predict the malignant potential of gastric GISTs with high accuracy.

Gastroduodenal Intussusception of a Gastrointestinal Stromal Tumor: A Rare Cause of Acute Pancreatitis

Patients with symptomatic gastrointestinal stromal tumor (GIST) typically present with gastrointestinal bleeding and abdominal pain. This report presents an unusual case of fundic GIST complicated by gastroduodenal intussusception, manifesting as acute pancreatitis. The patient presented with epigastric pain and pancreatic enzyme elevation; thus, he was diagnosed with acute pancreatitis. Computed tomography showed evidence of pancreatitis and a 4×4.7 cm well-defined hyperdense lesion in the 2nd part of the duodenum, compressing the pancreatic head and pancreatic duct. Esophagogastroduodenoscopy revealed invagination of the gastric folds into the duodenum, causing pyloric canal blockage consistent with gastroduodenal intussusception. Spontaneous reduction of the lesion during endoscopy revealed a 4 cm pedunculated subepithelial mass with central ulceration originating from the gastric fundus. Endoscopic ultrasound demonstrated a heterogeneous hypoechoic lesion originating from the 4th layer of the gastric wall. Laparoscopic-endoscopic intragastric wedge resection of the fundic lesion was subsequently performed, and surgical histology confirmed GIST.

Polypoid lesions detected in the upper gastrointestinal endoscopy: A retrospective analysis in 19560 patients, a single-center study of a 5-year experience in Turkey

OBJECTIVE:

In our study, we aimed to evaluate the endoscopic features such as prevalence and localization of polypoid lesions determined by us using esophagogastroduodenoscopy and histopathological characteristics of biopsy specimens taken in detail.

METHODS:

The data of 19,560 patients undergoing upper gastrointestinal endoscopy for any reason between 2009 and 2015 in our endoscopy unit were screened retrospectively and endoscopic and histopathological findings were analyzed in detail.

RESULTS:

In our study, the polypoid lesion was detected in 1.60% (n=313) of 19,560 patients. The most common localization of the polypoid lesions was determined to be gastric localization (n=301, 96.2%) and antrum with a rate of 33.5% (n=105). When 272 patients in whom biopsy specimen could be taken was investigated, the most frequently seen lesion was polyp (n=115, 43.4%). Hyperplastic polyps (n=81, 29.8%) were the most frequently seen type among all polyps. In histopathological evaluation of the lesions, the prevalence rates of intestinal metaplasia (IM), surrounding tissue IM, atrophy, dysplasia, and neoplasia (adenocarcinoma, squamous cell carcinoma, gastrointestinal stromal tumor, neuroendocrine tumor, and metastatic tumor) among premalignant lesions were determined to be 16.9%, 11.2%, 4.1%, 1.1%, and 3.7%, respectively.

CONCLUSION:

Polypoid lesions can be seen in endoscopic investigations. In histopathological investigations, while the vast majority of these lesions are benign polyps, some of them are diagnosed as premalignant or malignant lesions. In our study, we determined malignant lesions higher than the similar studies in the literature. This condition shows how effective endoscopic procedure and histopathological evaluation are of vital importance.

A multivariate prediction model for high malignancy potential gastric GI stromal tumors before endoscopic resection

BACKGROUND AND AIMS

Endoscopic resection is becoming an option in the management of gastric GI stromal tumors (GISTs). Although no consensus has been reached, patients with high malignancy potential GISTs are generally considered to be surgical candidates. However, no systematic preoperative evaluation strategy has yet been developed. The current study was performed to develop a preoperative multivariate model to predict the malignant potential of gastric GISTs.

METHODS

This study consisted of 2 stages. First, a multivariate prediction model for gastric GISTs smaller than 5 cm was developed using a multivariate logistic regression analysis in a retrospective cohort. Next, the prediction model was validated further in a validation cohort of gastric GISTs.

RESULTS

In the developing stage, 275 patients were included. The multivariate analysis demonstrated that independent risk factors for high malignancy potential gastric GISTs smaller than 5 cm were tumor size ≥2 cm (according to cutoff value), an irregular tumor shape, and mucosal ulceration (P < .05). Based on accordant regression coefficients, 3 risk factors were weighted with point values: 1 point for mucosal ulceration, 2 points for an irregular tumor shape, and 3 points for tumor size ≥2 cm. In the validation stage, 186 patients were included. The area under the curve of the prediction model was .80 (95% confidence interval, .73-.85), which was significantly higher than that of tumor size alone (P = .034).

CONCLUSIONS

The independent risk factors for high malignancy potential gastric GISTs smaller than 5 cm were tumor size larger than 2 cm, an irregular tumor shape, and mucosal ulceration. These factors could be used to predict malignancy potential of gastric GISTs in a simple combination.

British Society of Gastroenterology guidelines on the diagnosis and management of patients at risk of gastric adenocarcinoma

Gastric adenocarcinoma carries a poor prognosis, in part due to the late stage of diagnosis. Risk factors include Helicobacter pylori infection, family history of gastric cancer-in particular, hereditary diffuse gastric cancer and pernicious anaemia. The stages in the progression to cancer include chronic gastritis, gastric atrophy (GA), gastric intestinal metaplasia (GIM) and dysplasia. The key to early detection of cancer and improved survival is to non-invasively identify those at risk before endoscopy. However, although biomarkers may help in the detection of patients with chronic atrophic gastritis, there is insufficient evidence to support their use for population screening. High-quality endoscopy with full mucosal visualisation is an important part of improving early detection. Image-enhanced endoscopy combined with biopsy sampling for histopathology is the best approach to detect and accurately risk-stratify GA and GIM. Biopsies following the Sydney protocol from the antrum, incisura, lesser and greater curvature allow both diagnostic confirmation and risk stratification for progression to cancer. Ideally biopsies should be directed to areas of GA or GIM visualised by high-quality endoscopy. There is insufficient evidence to support screening in a low-risk population (undergoing routine diagnostic oesophagogastroduodenoscopy) such as the UK, but endoscopic surveillance every 3 years should be offered to patients with extensive GA or GIM. Endoscopic mucosal resection or endoscopic submucosal dissection of visible gastric dysplasia and early cancer has been shown to be efficacious with a high success rate and low rate of recurrence, providing that specific quality criteria are met.

Clinical evaluation of endoscopic resection for treatment of large gastric stromal tumors

BACKGROUND

Gastric stromal tumor is a digestive tract mesenchymal tumor with malignant potential, and endoscopic techniques have been widely used in the treatment of gastric stromal tumors, but there is still controversy over their use for large gastric stromal tumors (≥ 3 cm).

AIM

To evaluate the clinical long-term efficacy and safety of endoscopic resection for large (≥ 3 cm) gastric stromal tumors.

METHODS

All patients who underwent endoscopic resection or surgery at our hospital from 2012 to 2017 for pathologically confirmed gastric stromal tumor with a maximum diameter of ≥ 3 cm were collected. The clinical data, histopathologic characteristics of the tumors, and long-term outcomes were recorded.

RESULTS

A total of 261 patients were included, including 37 patients in the endoscopy group and 224 patients in the surgical group. In the endoscopy group, the maximum tumor diameter was 3-8 cm; the male: Female ratio was 21/16; 34 cases had low-risk tumors, 3 had intermediate-risk, and 0 had high-risk; the mean follow-up time was 30.29 ± 19.67 mo, no patient was lost to follow-up, and no patient received chemotherapy after operation; two patients with recurrence had low-risk stromal tumors, and neither had complete resection under endoscopy. In the surgical group, the maximum tumor diameter was 3-22 cm; the male: Female ratio was 121/103; 103 cases had low-risk tumors, 75 had intermediate-risk, and 46 had high-risk; the average follow-up time was 38.83 ± 21.50 mo, 53 patients were lost to follow-up, and 8 patients had recurrence after operation (6 cases had high-risk tumors, 1 had intermediate-risk, and 1 had low-risk). The average tumor volume of the endoscopy group was 26.67 ± 26.22 cm³ (3.75-120), all of which were less than 125 cm³. The average volume of the surgical group was 273.03 ± 609.74 cm³ (7-4114). Among all patients with a tumor volume < 125 cm³, 7 with high-risk stromal tumors in the surgical group (37.625 cm³ to 115.2 cm³) accounted for 3.8% (7/183); of those with a tumor volume < 125 cm³, high-risk patients accounted for 50% (39/78). We found that 57.1% (12/22) of patients with high-risk stromal tumors also had endoscopic surface ulcer bleeding and tumor liquefaction on ultrasound or abdominal computed tomography; the ratio of tumors positive for both in high-risk stromal tumors with a volume < 125 cm³ was 60% (3/5).

CONCLUSION

Endoscopic treatment is safe for 95.5% of patients with gastric stromal tumors with a tumor diameter ≥ 3 cm and a volume of < 125 cm³ without endoscopic surface ulcer bleeding or CT liquefaction.

Efficacy and safety of endoscopic resection for small submucosal tumors originating from the muscularis propria layer in the gastric fundus

BACKGROUND

Gastric small submucosal tumors (SMTs) are becoming increasingly common. However, the fundus of stomach is regarded as a difficult area for endoscopic resection (ER). In this study, we investigated the efficacy, safety, and long-term outcomes of ER for small SMTs of the gastric fundus in a large series of patients, research that was previously lacking.

METHODS

537 consecutive patients with SMTs no more than 20 mm in diameter, occurring in the gastric fundus and originating from the muscularis propria layer, which were treated with endoscopic submucosal excavation or endoscopic full-thickness resection (EFTR) were included in this retrospective study at Zhongshan Hospital of Fudan University from January 2013 to September 2016. Clinicopathological, endoscopic, and follow-up data were collected and analyzed.

RESULTS

En bloc resection was achieved in 100% of patients, and complete resection was achieved for 530 (98.7%) lesions. Although the total rate of complications was 9.3%, few serious adverse events occurred in only three (0.6%) patients, including major pneumoperitoneum, major hydrothorax, and bleeding. Unlike lager tumor sizes and longer procedure times, endoscopist experience had a positive impact on decreasing the likelihood of complications. Based on statistical analysis, tumors with greater size near the cardia, which were treated by EFTR, were the significant contributors to longer operative times. A median follow-up of 32 months was available, and all patients were free from local recurrence or distant metastasis during the study period.

CONCLUSIONS

Although the gastric fundus presents technical difficulties, ER is effective for the resection of small gastric SMTs with a high complete resection rate and rare serious adverse events.

Effectiveness and safety of endoscopic resection for gastric GISTs: a systematic review

AIMS

To evaluate the effectiveness and safety of endoscopic resection for gastric gastrointestinal stromal tumors (GISTs).

MATERIAL AND METHODS

The effectiveness and safety of endoscopic resection were mainly assessed by complete resection rate, postoperative adverse event rate, and recurrence rate. Moreover, a comparison of endoscopic with laparoscopic resection for gastric GISTs was made through weighted mean difference by STATA 12.0 with regard to operation time, blood loss, and length of stay after including patients who underwent endoscopic or laparoscopic resection for gastric GISTs in the comparative studies.

RESULTS

Eleven studies investigating endoscopic resection for GISTs were included. For stromal tumors <2 cm in average diameters the pooled rates of complete resection, postoperative adverse events and recurrence were 0.97, 0.08, and 0.03, respectively. Only five retrospective studies directly compared endoscopic with laparoscopic resection for gastric GISTs with average diameters from 1.1 cm to 3.8 cm, and endoscopic resection had a shorter operation time than laparoscopic resection, but there were no significant differences in intraoperative blood loss, length of stay, postoperative complications, and postoperative recurrence rates between the two approaches.

CONCLUSIONS

Endoscopic resection is predominantly tried for gastric GISTs of relatively small size. It seems effective and safe for gastric GISTs <2 cm in average diameter, with relatively short operation times.

Gastric polyps: Association with Helicobacter pylori status and the pathology of the surrounding mucosa, a cross sectional study

AIM: To assess the endoscopic characteristics of gastric polyps and their association with Helicobacter pylori (H. pylori) status in a predominantly Hispanic population.

METHODS: We conducted a retrospective study of all esophagogastroduodenoscopies performed at our institution. Demographic, endoscopic and histopathological data were reviewed. Categorization of patients into Hispanic and Non-Hispanic was based on self-identification. Patients without resection/biopsy were not included in the analysis. Identification of polyps type was based on histological examination. One way analysis of variance was used to compare continuous variables among different polyp types and Fisher’s exact test was used compare categorical variables among polyp types. Unadjusted and adjusted comparisons of demographic and clinical characteristics were performed according to the H. pylori status and polyp type using logistic regressions.

RESULTS: Of 7090 patients who had upper endoscopy, 335 patients had gastric polyps (4.7%). Resection or biopsy of gastric polyps was performed in 296 patients (88.4%) with a total of 442 polyps removed or biopsied. Of 296 patients, 87 (29%) had hyperplastic polyps, 82 (28%) had fundic gland polyps and 5 (1.7%) had adenomatous polyps. Hyperplastic polyps were significantly associated with positive H. pylori status compared with fundic gland polyps (OR = 4.621; 95%CI: 1.92-11.13, P = 0.001). Hyperplastic polyps were also found to be significantly associated with portal hypertensive gastropathy compared with fundic gland polyps (OR = 6.903; 95%CI: 1.41-33.93, P = 0.0174). Out of 296 patients, 30 (10.1%) had a follow-up endoscopy with a mean duration of 26 ± 16.3 mo. Interval development of cancer was not noted in any of the patients during follow up period.

CONCLUSION: Gastric hyperplastic polyps were significantly associated with positive H. pylori status and portal hypertensive gastropathy as compared with fundic gland polyps.

Leiomyosarcoma of the small bowel: Report of a case and review of the literature

INTRODUCTION

Leiomyosarcoma of the small bowel is an extremely rare form of gastrointestinal malignancy. Small bowel tumours are usually asymptomatic at the early stages, and difficult to visualise by upper and lower endoscopy.

PRESENTATION OF CASE

An 83-year-old gentleman presented in surgical outpatient clinic with chronic anaemia, abdominal discomfort and a single episode of malaena. Initial OGD and colonoscopy were both unremarkable. Subsequent CT revealed a mass in the right iliac fossa of likely small bowel origin, leading to an urgent laparotomy and resection with primary anastomosis. Histopathology showed a high grade leiomyosarcoma with no signs of metastasis and confirmatory immunological staining. Post-surgery follow up remains unremarkable.

DISCUSSION

Leiomyosarcomas of the small bowel are extremely rare entities, particularly following the advent of robust immunohistological diagnostic methods allowing differentiation from GISTs. As small bowel tumours are often not visualised by upper and lower endoscopy, further investigations to visualise the small bowel are crucial, generally in the form of magnetic resonance enterography, CT colonography or wireless capsule endoscopy.

CONCLUSION

The treatment of such tumours remains predominantly centred around surgical resection, and prognosis is dependent on tumour size and histological staging.

Advances in research of gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract, arising from the interstitial cells of Cajal (ICCs), primarily in the stomach and small intestine. The growth of most GISTs is driven by the mutations of genes encoding oncogenic receptor tyrosine kinase KIT or platelet derived growth factor receptor alpha (PDGFRα). The pathogenesis of GISTs may involve ICCs, microRNAs (miRNAs), signaling pathways, DNA methylation, and KIT or PDGFRα gene mutations. This article systematically describes the advances in research of GISTs in terms of clinical features, imaging characteristics, endoscopic features, histopathological features, diagnosis and therapies.

Coexpression of two distinct muscle acetylcholine receptor alpha-subunits during development

The nicotinic acetylcholine receptor is a ligand-gated channel that mediates signalling at the vertebrate neuromuscular junction. It is a pentameric complex of four different subunits, assembled with a stoichiometry of alpha 2 beta gamma delta. Muscle-like alpha-subunits have been cloned from Torpedo, mouse, calf, rat, chicken, human and Xenopus, and only a single alpha-subunit complementary DNA from each species has been detected. We report here the cloning and characterization of a second muscle alpha-subunit cDNA from Xenopus, and show that this and a previously reported Xenopus alpha-subunit cDNA are encoded by distinct genes. The novel alpha-subunit reported here is expressed uniquely in oocytes; but both types of alpha-subunit are coexpressed throughout muscle development. This latter observation indicates that the expression of these two alpha-subunits is different from a previously reported developmental 'subunit-switch' mechanism used to generate channel diversity.