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

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

KEY POINTS

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

Artificial intelligence-assisted endoscopic ultrasound in the diagnosis of gastrointestinal stromal tumors: a meta-analysis

BACKGROUND AND AIMS

Endoscopic ultrasonography (EUS) is useful for the diagnosis of gastrointestinal stromal tumors (GISTs), but is limited by subjective interpretation. Studies on artificial intelligence (AI)-assisted diagnosis are under development. Here, we used a meta-analysis to evaluate the diagnostic performance of AI in the diagnosis of GISTs using EUS images.

METHODS

PubMed, Ovid Medline, Embase, Web of science, and the Cochrane Library databases were searched for studies based on the EUS using AI for the diagnosis of GISTs, and a meta-analysis was performed to examine the accuracy.

RESULTS

Overall, 7 studies were included in our meta-analysis. A total of 2431 patients containing more than 36,186 images were used as the overall dataset, of which 480 patients were used for the final testing. The pooled sensitivity, specificity, positive, and negative likelihood ratio (LR) of AI-assisted EUS for differentiating GISTs from other submucosal tumors (SMTs) were 0.92 (95% confidence interval [CI] 0.89-0.95), 0.82 (95% CI 0.75-0.87), 4.55 (95% CI 2.64-7.84), and 0.12 (95% CI 0.07-0.20), respectively. The summary diagnostic odds ratio (DOR) and the area under the curve were 64.70 (95% CI 23.83-175.69) and 0.950 (Q* = 0.891).

CONCLUSIONS

AI-assisted EUS showed high accuracy for the automatic endoscopic diagnosis of GISTs, which could be used as a valuable complementary method for the differentiation of SMTs in the future.

Efficacy of ultrasound endoscopy with artificial intelligence for the differential diagnosis of non-gastric gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are common subepithelial lesions (SELs) and require treatment considering their malignant potential. We recently developed an endoscopic ultrasound-based artificial intelligence (EUS-AI) system to differentiate GISTs from non-GISTs in gastric SELs, which were used to train the system. We assessed whether the EUS-AI system designed for diagnosing gastric GISTs could be applied to non-gastric GISTs. Between January 2015 and January 2021, 52 patients with non-gastric SELs (esophagus, n = 15; duodenum, n = 26; colon, n = 11) were enrolled. The ability of EUS-AI to differentiate GISTs from non-GISTs in non-gastric SELs was examined. The accuracy, sensitivity, and specificity of EUS-AI for discriminating GISTs from non-GISTs in non-gastric SELs were 94.4%, 100%, and 86.1%, respectively, with an area under the curve of 0.98 based on the cutoff value set using the Youden index. In the subanalysis, the accuracy, sensitivity, and specificity of EUS-AI were highest in the esophagus (100%, 100%, 100%; duodenum, 96.2%, 100%, 0%; colon, 90.9%, 100%, 0%); the cutoff values were determined using the Youden index or the value determined using stomach cases. The diagnostic accuracy of EUS-AI increased as lesion size increased, regardless of lesion location. EUS-AI based on gastric SELs had good diagnostic ability for non-gastric GISTs.

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.

Transperineal core-needle biopsy of a rectal subepithelial lesion guided by endorectal ultrasound after contrast-enhanced ultrasound: A case report

BACKGROUND

Rectal subepithelial lesions (SELs) are commonly seen in endoscopic examination, generally manifested as bumps with a smooth surface. Precise preoperative diagnoses for rectal SELs are difficult because abnormal tissues are not easily to be obtained by regular endoscopic forceps biopsy. Traditional guidance modalities of preoperative biopsy, including endoscopic ultrasound, computed tomography, and transabdominal ultrasound, are often unsatisfactory. An updated, safe, and effective biopsy guidance method is required. We herein report a new biopsy guidance modality—endorectal ultrasound (ERUS) combined with contrast-enhanced ultrasound (CEUS).

CASE SUMMARY

A 32-year-old woman complained of a mass inside the rectovaginal space for 9 years, which became enlarged within 1 year. A rectal SEL detected by endoscopy was suspected to be a gastrointestinal stromal tumor or exophytic uterine fibroid. Pathological diagnosis was difficult because of unsuccessful transabdominal core needle biopsy with insufficient tissues, as well as vaginal hemorrhage. A second biopsy was suggested after multiple disciplinary treatment discussion, which referred to a transperineal core needle biopsy (CNB) guided by ERUS combined with CEUS. Adequate samples were procured and rectal gastrointestinal stromal tumor was proved to be the pathological diagnosis. Imatinib was recommended for first-line therapy by multiple disciplinary treatment discussion. After the tumor shrunk, resection of the rectal gastrointestinal stromal tumor was performed through the posterior vaginal wall. Adjuvant therapy was applied and no recurrence or metastasis has been found by the last follow-up on December 13, 2019.

CONCLUSION

Transperineal CNB guided by ERUS and CEUS is a safe and effective preoperative biopsy of rectal SELs yet with some limitations.

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

PURPOSE

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

Efficacy of endoscopic ultrasound with artificial intelligence for the diagnosis of gastrointestinal stromal tumors

BACKGROUND

Although endoscopic ultrasound (EUS) is reported to be suitable for determining the layer from which subepithelial lesions (SELs) originate, it is difficult to distinguish gastrointestinal stromal tumor (GIST) from non-GIST using only EUS images. If artificial intelligence (AI) can be used for the diagnosis of SELs, it should provide several benefits, including objectivity, simplicity, and quickness. In this pilot study, we propose an AI diagnostic system for SELs and evaluate its efficacy.

METHODS

Thirty sets each of EUS images with SELs ≥ 20 mm or < 20 mm were prepared for diagnosis by an EUS diagnostic system with AI (EUS-AI) and three EUS experts. The EUS-AI and EUS experts diagnosed the SELs using solely the EUS images. The concordance rates of the EUS-AI and EUS experts' diagnoses were compared with the pathological findings of the SELs.

RESULTS

The accuracy, sensitivity, and specificity for SELs < 20 mm were 86.3, 86.3, and 62.5%, respectively for the EUS-AI, and 73.3, 68.2, and 87.5%, respectively, for the EUS experts. In contrast, accuracy, sensitivity, and specificity for SELs ≥ 20 mm were 90.0, 91.7, and 83.3%, respectively, for the EUS-AI, and 53.3, 50.0, and 83.3%, respectively, for the EUS experts. The area under the curve for the diagnostic yield of the EUS-AI for SELs ≥ 20 mm (0.965) was significantly higher than that (0.684) of the EUS experts (P = 0.007).

CONCLUSION

EUS-AI had a good diagnostic yield for SELs ≥ 20 mm. EUS-AI has potential as a good option for the diagnosis of SELs.

Gastric Calcifying Fibrous Tumor: An Easy Misdiagnosis as Gastrointestinal Stromal Tumor-A Systemic Review

Background and Objectives: Calcifying fibrous tumor (CFT) in the stomach is extremely rare and is easily misdiagnosed as a gastrointestinal stromal tumor (GIST). This study aims to determine the best method to differentiate between gastric CFT and GIST after a systemic review and meta-analysis. Materials and Methods: A systematic search of articles using electronic databases (MEDLINE, EMBASE, and LILACS) was conducted and resulted in 162 articles with 272 CFT cases published from January 1988 to September 2019. Results: Of these cases, 272 patients, 60 patients with gastric CFT (32 men and 28 women, mean age 49.2 years) were analyzed. The mean tumor size was 2.4 cm in patients with gastric CFT. Both endoscopic ultrasound (EUS) and computed tomography (CT) findings revealed well-defined (100% vs. 77.8%), heterogeneous (100% vs. 77.8%), iso-hypoechoic (71.4% vs. 33.3%), and calcified (85.7% vs. 77.8%) lesions, respectively. The majority of patients (53.3%) were symptomatic, with the most common symptom being abdominal discomfort (55.6%). None of the patients with gastric CFT showed recurrence after treatment, and most patients received nonendoscopic treatment (56%, n = 28/50). Both age and tumor size were statistically significant in patients with gastric CFT than GIST (49.2 vs. 65.0 years and 2.4 vs. 6.0 cm; both p < 0.001). The ratio of children among patients with CFT (5%) and GIST (0.05%) was also significantly different (p = 0.037). The calcification rates of gastric CFT had significantly higher calcification rates than GIST on images of EUS and CT (85.7% vs. 3.6% and 77.8% vs. 3.6%; both p < 0.001). Conclusions: Compared with patients with GIST, patients with gastric CFT were younger, had smaller tumor size, and were symptomatic. Furthermore, gastric CFT was well-defined, heterogeneous in the third layer, and had high calcification rates on the images.

Recent advances in the management of gastrointestinal stromal tumor

Gastrointestinal stromal tumor (GIST) is a rare but an important clinical entity seen in our clinical practice. It is the most common mesenchymal tumor of the gastrointestinal tract and most common malignancy of the small intestine. Although the exact prevalence of GIST is not known, the incidence of GIST has been increasing. GISTs arise from interstitial cells of Cajal. Most of the GISTs occur due to mutation in c-kit gene or platelet derived growth factor receptor alpha gene. 15% of GISTs do not have these mutations and they are called wild-type GISTs. Almost all GISTs express KIT receptor tyrosine kinase. Histologically, GISTs look like spindle cell tumors most of the time but they can be epitheloid or mixed type. The median size of GISTs varies from 2.7 cm to 8.9 cm. Clinically, patients with small GISTs remain asymptomatic but as the GIST size increases, patients present with various symptoms depending on the location of the GIST. Most of GISTs are located in the stomach or small bowel. Diagnosis is suspected on imaging and endoscopic studies, and confirmed by tissue acquisition with immunohistochemical staining. The aggressiveness of GISTs depends on the size, mitotic index and location. Surgical resection is the treatment of choice. But various endoscopic modalities of resection are increasingly being tried. Tyrosine kinase inhibitors are extremely useful in the management of large GISTs, unresectable GISTs and metastatic GISTs. Treatment options for metastatic GISTs also include radiotherapy, chemotherapy, hepatic artery embolization, chemoembolization and radiofrequency ablation.

Gastrointestinal stromal tumour of stomach: Feasibility of laparoscopic resection in large lesions and its long-term outcomes

Background:

Gastric gastrointestinal stromal tumours (GISTs) are rare neoplasms that require excision for cure. Although the feasibility of laparoscopic resection of smaller gastric GIST has been established, the feasibility and long-term efficacy of these techniques are unclear in larger lesions. This study is done to assess the feasibility of the laparoscopic resection of gastric GISTs and their long-term outcomes.

Methods:

Patients who underwent laparoscopic resection of gastric GISTs were identified in a prospectively collected database. Outcome measures included patient demographics, operative findings, morbidity and histopathologic characteristics of the tumour. Patient and tumour characteristics were analysed to identify risk factors for tumour recurrence.

Results:

There were 42 patients with a mean age of 56.7 years and had a mean tumour size was 4.5 ± 2.7 cm. Laparoscopic wedge resection was the most common procedure done. There were no major perioperative complications or mortalities. All lesions had negative resection margins. At a mean follow-up of 48 months, 36/39 (92.3%) patients were disease free and 3/39 (7.6%) had progressive disease. Univariate analysis showed that there was a statistically significant association of disease progression with tumour size, high mitotic index, tumour ulceration and tumour necrosis. The presence of >10 mitotic figures/50 high-power field was an independent predictor of disease progression.

Conclusion:

Our study establishes laparoscopic resection is feasible and safe in treating gastric GISTs for tumours >5 cm size. The long-term disease-free survival in our study shows acceptable oncological results in comparison to historical open resections.

Utility of EUS elastography in the diagnosis of gastric subepithelial tumors: a pilot study (with video)

BACKGROUND AND AIMS

EUS elastography is a real-time imaging technique that analyzes tissue elasticity. The aim of this study was to investigate the applicability of quantitative EUS elastography in the differential diagnosis of gastric subepithelial tumors (SETs).

METHODS

We prospectively registered 41 consecutive patients with gastric SETs and measured their strain ratios with EUS elastography. The strain ratios of gastric SETs were compared with the histopathologic diagnosis.

RESULTS

Thirty-one patients (mean age, 51.4 ± 12.6 years) were included in the analysis. The mean size of the SETs was 2.3 ± 0.7 cm. Lipomas had the lowest strain ratio of 1.6 (1.1-2.0), followed by leiomyomas 6.0 (2.0-29.0), ectopic pancreas 11.8 (1.7-29.3), gastrointestinal stromal tumors (GISTs) 51.1 (29.0-67.0), and schwannomas 62.0. With a cut-off value of 22.7, EUS elastography could differentiate GISTs from leiomyomas with sensitivity and specificity of 100% and 94.1%, respectively (P = .001; 95% confidence interval, 0.979-1.000).

CONCLUSIONS

EUS elastography could be a promising diagnostic adjunct for the assessment of gastric SETs, especially in differentiating GISTs from leiomyomas.

Multiband mucosectomy versus endoscopic submucosal dissection and endoscopic submucosal excavation for GI submucosal tumors: short and long term follow-up

AIMS

To evaluate the short- and long-term outcomes of 3 different endoscopic dissection techniques for upper gastrointestinal (GI) submucosal tumours (SMTs).

METHODS

Data for 135 patients withGI SMTs who underwent multiband mucosectomy (MBM), endoscopic submucosal dissection (ESD), or endoscopic submucosal excavation (ESE) were retrospectively assessed. The en bloc resection rate, endoscopic complete resection rate, operation time, potential complications and local recurrence rate were compared.

RESULTS

No significant differences were observed in the rate of endoscopic complete resections and pathologic complete resections among the three groups. For SMTs > 15 mm in width, the lowest en bloc resection rate was found for MBM (P = 0.000). MBM was also associated with the shortest procedure time, lowest perforation rate and lowest rate of major bleeding. ESE was the most effective procedure for muscularis propria (MP) lesions but was associated with the longest operation time (P < 0.01). The ESD and ESE groups had similar perforation rates (P > 0.05). No differences were observed in 4-year local recurrence rates among the groups (P = 0.945).

CONCLUSIONS

MBM is a simple and effective method for the treatment of small SMTs and achieves clinical success rates similar to those of ESD and ESE. However, ESD and ESE are preferable for larger and deep lesions and are associated with a longer operation time. Nonetheless, all 3 techniques resulted in a low 4-year local recurrence rate. Large-scale randomized clinical trials are needed to further investigate these results.

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.

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.

Evaluation of Gastric Emptying by Transabdominal Ultrasound after Oral Administration of Semisolid Cellulose-Based Gastric Ultrasound Contrast Agents

Many previous studies have found that transabdominal ultrasound may allow precise measurement of gastric emptying of liquid meals. However, the clinical use of this technique has been hampered by the limitation that transabdominal ultrasound might not accurately measure gastric emptying of solid meals. It is more important to measure gastric emptying of solids instead of liquids, as gastric emptying of solids is more often delayed than gastric emptying of liquids in gastric motility disorders. Recently, transabdominal ultrasound after oral administration of a cellulose-based gastric contrast agents (TUS-OSCA) has been suggested to be effective in initial screening of gastric lesions. The aim of this study was to explore the accuracy of TUS-OSCA in the evaluation of gastric emptying of a semisolid meal. Twenty healthy young patients (10 males and 10 females aged 25.5 ± 2.5 y) were studied. Concurrent measurements of gastric emptying by scintigraphy and TUS-OSCA were performed after ingestion of 350 mL semisolid ultrasound agent labeled with 20 MBq ^99mTc-sulfur colloid. There was no significant difference in the overall curves for gastric emptying time between scintigraphy and TUS-OSCA. There was a good correlation between the gastric 50% emptying times determined by scintigraphy (89.4 ± 1.8 min) and TUS-OSCA (92.5 ± 1.7 min). The correlation coefficient was r = 0.922 (p = 0.000). Current results indicate that TUS-OSCA is accurate, and the results are similar to those obtained by scintigraphy for gastric emptying of a semisolid meal.

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

BACKGROUND AND STUDY AIMS

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

Endoscopic resection of gastric gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the gastrointestinal tract, and about 60% of them are found in the stomach. With the widespread application of endoscopy and endoscopic ultrasonography (EUS), more and more gastric GISTs are being found in an early stage (with a relative small diameter and no metastasis), giving the chance of complete resection. Endoscopic resection such as endoscopic band ligation (EBL), endoscopic submucosal dissection (ESD), endoscopic submucosal excavation (ESE), endoscopic full-thickness resection (EFTR) and submucosal tunneling endoscopic resection (STER), is a minimally invasive method compared with the conventional surgical approaches (open or laparoscopic), and has been demonstrated to be safe and effective for treating gastric GISTs. This review summarizes the recent advances on endoscopic resection of gastric GISTs, aiming to provide a rational management strategy for gastric GISTs.

Role of endoscopic ultrasound and endoscopic resection for the treatment of gastric schwannoma

Endoscopic ultrasound (EUS) and endoscopic resection play an important role in gastric submucosal tumor. However, there were few articles regarding EUS and endoscopic resection of gastric schwannomas. Our aim was to evaluate the role of EUS and endoscopic resection in treating gastric schwannomas.We retrospectively reviewed 14 patients between March 2012 and April 2016 with gastric schwannomas and who received EUS and endoscopic resection. EUS characteristics, endoscopic resection, tumor features, and follow-up were evaluated in all the patients.Fourteen patients were enrolled in the present study. The patients' ages ranged from 25 to 72 years (mean age, 52.6 years). On EUS, all tumors were originating from muscularis propria and hypoechoic. Ten tumors have the extraluminal growth patterns and 4 tumors have the intraluminal growth patterns. Marginal halos were observed in 7 lesions. No cystic change and calcification were found inside the lesions. Complete endoscopic resection was performed in all the patients with no complications occurring in any patients. No recurrence or metastases was found in all patients during the follow-up period.Gastric schwannoma has some characteristics on EUS, but it is difficult to differentiate gastric schwannoma from gastrointestinal stromal tumor. Endoscopic resection is an effective and safe treatment for gastric schwannoma with an excellent follow-up outcome.

Management of Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasm of the gastrointestinal tract. The stomach is the most common site of origin. Management of GISTs changed after the introduction of molecularly targeted therapies. Although the only potentially curative treatment of resectable primary GISTs is surgery, recurrence is common. Patients with primary GISTs at intermediate or high risk of recurrence should receive imatinib postoperatively. Imatinib is also first-line therapy for advanced disease. Cytoreductive surgery might be considered in advanced GIST for patients with stable/responding disease or limited focal progression on tyrosine kinase inhibitor therapy. GIST requires multidisciplinary management.

Subepithelial rectal gastrointestinal stromal tumor - the use of endoscopic ultrasound-guided fine needle aspiration to establish a definitive cytological diagnosis: a case report

Background

Gastrointestinal stromal tumors are the most common mesenchymal neoplasms affecting the gastrointestinal tract. The stomach is the most common location to be affected, and the rectum one of the rarest, but the whole gastrointestinal tract remains susceptible. Gastrointestinal stromal tumors account for only 0.1% of rectal tumors. Currently, endoscopic ultrasound plays an essential role in the diagnostic process of gastrointestinal stromal tumors, especially when the affected sites have a worse outcome and higher morbidity rates.

Case presentation

We describe the case of a 68-year-old white Japanese man with a history of long-term mild rectal pain and tenesmus. A digital rectal examination revealed a right palpable solid mass ranging from 3 to 7 cm from his anal verge. A colonoscopy was performed and showed a 5 cm elevated lesion covered by normal mucosa, located 4 cm above the pectineal line. Endoscopic ultrasound confirmed the diagnosis of a homogeneous hypoechoic mass with areas of necrosis as a rectal subepithelial lesion originating at the fourth layer (muscularis propria). He then underwent endoscopic ultrasound-guided fine needle aspiration of the lesion, followed by cytological and immunohistochemistry evaluation. The evaluation showed spindle and epithelioid cells of variable sizes, in fascicles separated by stroma, which reacted firmly and consistently to CD117/c-kit and CD34, and negative to desmin and S-100 protein. There was weak staining for nuclear Ki-67 in the tumor cells. A diagnosis of rectal gastrointestinal stromal tumor was confirmed. After a multidisciplinary meeting, an abdominoperineal resection of his rectum was performed. The pathology of the specimen confirmed the diagnosis of rectal gastrointestinal stromal tumor. He is now asymptomatic after 3 months’ follow-up and is on adjuvant therapy with a tyrosine-kinase inhibitor.

Conclusions

Gastrointestinal stromal tumors are rare tumors, and among the variety of primary location sites, the rectum is one of the rarest. The localization of this type of tumor has worse outcomes and higher morbidity rates. We report this rare case to emphasize the need for precise diagnosis and the important role of endoscopic ultrasound-guided fine needle aspiration in such situations.

Application of laparoscopy, endoscopy and laparoscopic and endoscopic cooperative surgery in gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) constitute the most common mesenchymal neoplasms of the gastrointestinal tract, among which 60%-70% are located in the stomach. All GISTs have malignant potential, varying from small lesions to aggressive sarcomas. Surgical resection with negative margins remains the best treatment for GISTs. Lymphadenectomy is not necessary because GISTs rarely metastasize to lymph nodes. Because of these biological behavior characteristics, the advantages of minimally invasive surgeries such as laparoscopic surgery and endoscopic surgery can be fully reflected in the surgical management of GISTs. The advent of laparoscopic and endoscopic cooperative surgery has broadened the scope and enhanced the safety of minimally invasive surgical treatment of GISTs. In this paper we will discuss the application of laparoscopy, endoscopy and laparoscopic and endoscopic cooperative surgery in the treatment of GISTs.