Diagnosis of gastrointestinal stromal tumors: a consensus approach

A systematic review and meta-analysis of neoadjuvant imatinib use in locally advanced and metastatic gastrointestinal stromal tumors

BACKGROUND

Several doubts remain regarding the optimal use of neoadjuvant imatinib in gastrointestinal stromal tumors (GISTs), such as ideal treatment duration, patient selection, and long-term survival outcomes. This manuscript provides a comprehensive review on neoadjuvant imatinib treatment outcomes and facilitate evidence-based decision-making for the use of imatinib therapy in GISTs.

METHODS

Four databases (PubMed, EMBASE, Scopus, and Cochrane Library) were searched from inception to September 9, 2023. Meta-analyses of proportions were performed for the outcomes of R0 resection, disease responses, and 1-year, 3-year, and 5-year overall survival (OS) as well as 1-year, 3-year, and 5-year disease free survival (DFS). Sensitivity analyses in the form of leave-one-out analyses, meta-regression, and subgroup analyses were performed for outcomes with substantial statistical heterogeneity.

RESULTS

The search yielded 1254 articles, and 36 studies were included in our analysis. Meta-analysis of proportions revealed that 1-year, 3-year, and 5-year OS was 100%, 94%, and 88%, while 1-year, 3-year and 5-year DFS was 99%, 89%, and 79%, respectively. An R0 resection rate of 89% and a disease response rate of 67% was achieved after a mean duration of treatment of 8.41 ± 0.367 months. KIT exon 9 mutation was significantly associated with poorer 5-year DFS.

CONCLUSION

This study quantified key outcomes for neoadjuvant imatinib in locally advanced and metastatic or recurrent GIST. Patients with gastric and rectal tumous stand to benefit from neoadjuvant imatinib with an optimal treatment duration of 8 months. Furthermore, the potential utility of mutational analysis in guiding treatment with neoadjuvant imatinib was demonstrated.

Primary gastrointestinal stromal tumor of the liver: a case report

Introduction and importance

Primary gastrointestinal stromal tumors of the liver are exceedingly rare entities, presenting diagnostic and therapeutic challenges. The authors present a case of a 64-year-old male with a primary gastrointestinal stromal tumor (GIST) of the liver, emphasizing the importance of comprehensive diagnostic evaluation and multidisciplinary management in such uncommon cases.

Case presentation

The patient presented with persistent hypochondriac pain, leading to the discovery of a hepatic mass. Diagnostic work-ups, including imaging studies and biopsy, confirmed the diagnosis of primary GIST in the liver. Following thorough multidisciplinary consultation, the patient underwent right anterior segmentectomy of the liver, performed by our experienced surgeon. Postoperative pathology confirmed the diagnosis of GIST, and the patient was advised to use adjuvant imatinib.

Clinical discussion

Primary GISTs of the liver pose diagnostic challenges due to their rarity and varied clinical presentations. Imaging modalities, immunohistochemistry, and molecular genotyping are crucial in accurate diagnosis and treatment planning. Surgical resection remains the cornerstone of treatment for localized GISTs, with adjuvant therapy considered based on recurrence risk factors and molecular characteristics.

Conclusion

This case highlights the need for multidisciplinary consultation in managing primary GISTs of the liver. Accurate diagnosis, surgical expertise, and personalized adjuvant therapy are crucial for better patient outcomes. Further research is necessary to enhance our understanding of prognostic factors and treatment strategies for these rare tumors.

Gastrointestinal Stromal Tumors of the Stomach: Is There Any Advantage of Robotic Resections? A Systematic Review and Meta-Analysis

Background: The role of robotic surgery for gastrointestinal stromal tumor (GIST) resection remains unclear. This systematic review and meta-analysis aimed to investigate the outcomes of robotic versus laparoscopic surgery in patients requiring surgery for gastric GISTs. Methods: MEDLINE, EMBASE, and the Cochrane databases were searched from inception to September 4, 2023. Two independent reviewers conducted a systematic review of the literature to select all types of analytic studies comparing robotic versus laparoscopic surgery for GISTs and reporting intraoperative, postoperative, and/or pathological outcomes. Results: Overall, 4 retrospective studies were selected, including a total of 264 patients, specifically 111 (42%) in the robotic and 153 (58%) in the laparoscopic group. Robotic surgery was associated with longer operating time (+42.46 min; 95% confidence interval [CI]: 9.34, 75.58; P=0.01; I2: 85%) and reduced use of mechanical staplers (odds ratio [OR]: 0.05; 95%CI: 0.02, 0.11; P<0.00001; I2: 92%;) compared with laparoscopy. Although nonsignificant, conversion to open surgery was less frequently reported for robotic surgery (2.7%) than laparoscopy (5.2%) (OR: 0.59; 95%CI: 0.17, 2.03; P=0.4; I2: 0%). No difference was found for postoperative and oncological outcomes. Conclusions: Robotic surgery for gastric GISTs provides similar intraoperative, postoperative, and pathological outcomes to laparoscopy, despite longer operative time.

Preoperative CT-based radiomics and deep learning model for predicting risk stratification of gastric gastrointestinal stromal tumors

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are clinically heterogeneous with various malignant potential in different individuals. It is crucial to explore a reliable method for preoperative risk stratification of gastric GISTs noninvasively.

PURPOSE

To establish and evaluate a machine learning model using the combination of computed tomography (CT) morphology, radiomics, and deep learning features to predict the risk stratification of primary gastric GISTs preoperatively.

METHODS

The 193 gastric GISTs lesions were randomly divided into training set, validation set, and test set in a ratio of 6:2:2. The qualitative and quantitative CT morphological features were assessed by two radiologists. The tumors were segmented manually, and then radiomic features were extracted using PyRadiomics and the deep learning features were extracted using pre-trained Resnet50 from arterial phase and venous phase CT images, respectively. Pearson correlation analysis and recursive feature elimination were used for feature selection. Support vector machines were employed to build a classifier for predicting the risk stratification of GISTs. This study compared the performance of models using different pre-trained convolutional neural networks (CNNs) to extract deep features for classification, as well as the performance of modeling features from single-phase and dual-phase images. The arterial phase, venous phase and dual-phase machine learning models were built, respectively, and the morphological features were added to the dual-phase machine learning model to construct a combined model. Receiver operating characteristic (ROC) curves were used to evaluate the efficacy of each model. The clinical application value of the combined model was determined through the decision curve analysis (DCA) and the net reclassification index (NRI) was analyzed.

RESULTS

The area under the curve (AUC) of the dual-phase machine learning model was 0.876, which was higher than that of the arterial phase model or venous phase model (0.813, 0.838, respectively). The combined model had best predictive performance than the above models with an AUC of 0.941 (95% CI: 0.887-0.974) (p = 0.012, Delong test). DCA demonstrated that the combined model had good clinical application value with an NRI of 0.575 (95% CI: 0.357-0.891).

CONCLUSION

In this study, we established a combined model that incorporated dual-phase morphology, radiomics, and deep learning characteristics, which can be used to predict the preoperative risk stratification of gastric GISTs.

Long-term outcomes of endoscopic therapy versus surgical resection for 2-5 cm gastric gastrointestinal stromal tumors: A population-based comparative study

BACKGROUND

Endoscopic therapy (ET) of gastrointestinal stromal tumors (GIST) has become a viable treatment. We intended to compare long-term outcomes of ET versus surgical resection for 2-5 cm GIST using the Surveillance, Epidemiology, and End Results (SEER) database.

METHODS

A multicenter retrospective study was conducted to compare the long-term outcomes of patients treated with ET and surgical resection for GIST. The multivariate Cox proportional hazards models were used to identify predictors for patients survival. To balance the clinicopathologic characteristics, a 1:1 propensity score matching (PSM) was utilized.

RESULTS

A total of 749 patients with 2-5 cm GIST were enrolled, of whom 113 accepted ET and 636 underwent surgical resection. Before PSM, there was no significant difference in long-term outcomes between ET and surgical resection (5-year overall survival (OS): 93.5% vs. 91.6%, P=0.374; 5-year cancer-specific survival (CSS): 99.1% vs. 96.5%, P=0.546; 10-year OS: 71.1% vs. 78.2%, P=0.374; 10-year CSS: 93.6% vs. 92.7%, P=0.546). After adjusting for the relevant variables using the multivariable Cox proportional hazards models, we observed that the ET and surgical resection groups were similar in OS (HR 0.726, 95%CI 0.457-1.153, P=0.175) and CSS (HR 1.286, 95%CI 0.474-3.488, P=0.621). After PSM, the long-term OS and CSS of patients with 2-5 cm GIST after ET and surgical resection were comparable.

CONCLUSIONS

We found that the long-term survival of patients with 2-5 cm gastric GIST after ET and surgical resection were comparable. Further high-quality studies are needed to confirm the role of ET in 2-5 cm GIST.

A case report: Peritonitis secondary to perforated locally advanced gastrointestinal stromal tumor

INTRODUCTION AND IMPORTANCE

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms predominantly affecting the gastrointestinal tract. While they often remain asymptomatic, GISTs can lead to acute abdominal emergencies, such as peritonitis secondary to tumor perforation, a rare yet serious complication. Here, we present a unique case of a locally advanced ileal gastrointestinal stromal tumor complicated by generalized purulent peritonitis, emphasizing the diagnostic and management challenges associated with this condition.

CASE PRESENTATION

A 68-year-old male presented with worsening abdominal pain, vomiting, fever, and weight loss. Imaging studies revealed a large solid-cystic mass originating from the terminal ileum, prompting emergency surgery. Intraoperative findings included a multilobulated tumor mass invading the mesocolon, necessitating hemicolectomy. Histopathological analysis confirmed a high-risk gastrointestinal stromal tumor, leading to initiation of adjuvant therapy with imatinib mesylate.

CLINICAL DISCUSSION

GISTs often present with nonspecific symptoms, posing diagnostic challenges. Peritonitis secondary to tumor perforation is a rare yet critical complication requiring prompt surgical intervention. Complete resection remains the mainstay of treatment, with adjuvant imatinib therapy showing promise in high-risk cases.

CONCLUSION

This case report sheds light on the complexities of diagnosing and managing locally advanced gastrointestinal stromal tumors (GISTs) complicated by peritonitis. Complete tumor resection is crucial for potential cure, with adjuvant therapy using imatinib showing promise, especially in high-risk cases. Thorough diagnostic assessment, timely intervention, and comprehensive follow-up are essential for optimizing outcomes in complex GIST presentations.

Gastrointestinal Stromal Tumors Mimicking Ovarian Mass: A Case Report

Gastrointestinal stromal tumors (GIST) are common mesenchymal tumors of the gastrointestinal tract. Some somatic factors have been linked to an increased incidence risk. The diagnostic process for GIST poses difficulties since it bears limited resemblance to ovarian masses, given its manifestation through symptoms like abdominal pain, abdominal mass, fever, weight loss, and loss of appetite. Patients with GIST usually exhibit clinical symptoms and signs of an abdominal mass and chronic pelvic pain might look like an ovarian mass, and diagnosed as GIST on histological examination. A 50-year-old woman presented to the gynecology outpatient department with complaints of an abdominal lump accompanied by pain and decreased appetite persisting for five months, leading to a preliminary diagnosis of an ovarian mass. Further evaluation by histopathological examination was confirmed to be GIST on the final diagnosis.

Primary EGIST of the greater omentum - a rare presentation

Extragastrointestinal stromal tumors (EGISTs) are rare mesenchymal neoplasms, which develop in the retroperitoneum, mesentery, and omentum, lacking continuity to the stomach or intestines. Authors hereby present a female patient with a large heterogeneous abdominal mass as a case of an omental EGIST. A 46-year-old woman was referred to our hospital due to an insidious enlargement and colicky pain in the right iliac fossa. Abdominal palpation revealed a voluminous, freely mobile, and non-pulsatile mesoabdominal bulge expanding to the hypogastrium. On exploratory midline laparotomy, the tumor was densely fused to the greater omentum, not connected to the stomach, without gross involvement of adjacent structures. The large mass was completely excised after adequate mobilization. Immunohistochemical techniques showed strong and diffuse expression of WT1, actin and DOG-1, as well as multifocal c-KIT marking. Mutational study concluded a double mutation of KIT exon 9 and a mutation of PDGFRA exon 18. The patient was submitted to adjuvant treatment with imatinib mesylate 800 mg/day. Despite an extremely diverse presentation, omental EGISTs often remain clinically silent for a long time having enough space to grow before becoming symptomatic. These tumors have a consistent pattern of metastasis that typically spares lymph nodes unlike epithelial gut neoplasms. Surgery remains the preferred treatment for non-metastatic EGISTs of the greater omentum. It is possible that DOG-1 will supplant KIT as the leading marker in the future. The scarcity of knowledge on omental EGISTs implies a close monitoring of these patients to detect local relapse or distant metastasis.

Duodenal gastrointestinal stromal tumor presenting with life-threatening upper GI bleeding in a young patient: A case report and literature review

Key Clinical Message

Duodenal GISTs are rare and challenging tumors. Acute life-threatening upper GI bleeding is a possible presentation of duodenal GISTs. Surgery is the standard treatment for localized duodenal GISTs. Imatinib is an effective adjuvant therapy for duodenal GISTs.

Abstract

GIST is the most common mesenchymal neoplasm of the gastrointestinal tract, accounting for 1%-2% of gastrointestinal tumors. They originate from the interstitial cells of Cajal and are rare in patients younger than 30 years. The stomach is the most common site, followed by the small intestine and colon. GISTs are caused by a gain-of-function mutation in the proto-oncogene receptor tyrosine kinase, with activating mutations in KIT being the most common. Most GISTs are asymptomatic. Even if gastrointestinal bleeding is the most common complication life-threatening hemorrhage is extremely uncommon. We present a case of a 31-year-old male patient presented with massive active hematemesis and melena with hemorrhagic shock. The patient presented with massive hematemesis and melena of 1 h duration. Endoscopy showed pulsating active bleeding from the third part of the duodenum which was difficult to manage via endoscopy. Histopathologic evaluation showed spindle cell type GIST. Intraoperatively, there was a nodular mass with active bleeding on the third part of the duodenum. Duodenectomy with end-to-end anastomosis was done. Discharged with no postoperative complication and was put on imatinib. There are considerable challenges that arise in the diagnosis and treatment of duodenal gastrointestinal stromal tumors (GISTs) when they present with life-threatening upper gastrointestinal hemorrhage. In order to achieve the best possible outcomes for patients, it is crucial to have a comprehensive understanding of the clinical presentation, diagnostic methods, and treatment approaches.

Research progress on the pathogenesis of the SDHB mutation and related diseases

With the improvement of genetic testing technology in diseases in recent years, researchers have a more detailed and clear understanding of the source of cancers. Succinate dehydrogenase B (SDHB), a mitochondrial gene, is related to the metabolic activities of cells and tissues throughout the body. The mutations of SDHB have been found in pheochromocytoma, paraganglioma and other cancers, and is proved to affect the occurrence and progress of those cancers due to the important structural functions. The importance of SDHB is attracting more and more attention of researchers, however, reviews on the structure and function of SDHB, as well as on the mechanism of its carcinogenesis is inadequate. This paper reviews the relationship between SDHB mutations and related cancers, discusses the molecular mechanism of SDHB mutations that may lead to tumor formation, analyzes the mutation spectrum, structural domains, and penetrance of SDHB and sorts out some of the previously discovered diseases. For the patients with SDHB mutation, it is recommended that people in SDHB mutation families undergo regular genetic testing or SDHB immunohistochemistry (IHC). The purpose of this paper is hopefully to provide some reference and help for follow-up researches on SDHB.

Radiomics in gastrointestinal stromal tumours: an up-to-date review

Gastrointestinal stromal tumours are rare mesenchymal neoplasms originating from the Cajal cells and represent the most common sarcomas in the gastroenteric tract. Symptoms may be absent or non-specific, ranging from fatigue and weight loss to acute abdomen. Nowadays endoscopy, echoendoscopy, contrast-enhanced computed tomography, magnetic resonance imaging and positron emission tomography are the main methods for diagnosis. Because of their rarity, these neoplasms may not be included immediately in the differential diagnosis of a solitary abdominal mass. Radiomics is an emerging technique that can extract medical imaging information, not visible to the human eye, transforming it into quantitative data. The purpose of this review is to demonstrate how radiomics can improve the already known imaging techniques by providing useful tools for the diagnosis, treatment, and prognosis of these tumours.

Outcomes of Patients with Gastrointestinal Stromal Tumors in the Past Decade

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms of the gastrointestinal tract (GIT) that represent approximately 1 to 2 percent of primary gastrointestinal (GI) cancers. Owing to their rarity, very little is known about their overall epidemiology, and the prognostic factors of their pathology. The current study aimed to evaluate the independent determinants of mortality in patients diagnosed with GISTs over the past decade.

METHODS

Our study comprised 2374 patients diagnosed with GISTs from 2000 to 2017 from the Surveillance, Epidemiology, and End Results (SEER) database. We analyzed the baseline characteristics, and overall mortality (OM), as well as the cancer-specific mortality (CSM) of GISTs. Variables with a p value < 0.01 in the univariate Cox regression were incorporated into the multivariate Cox model, to determine the independent prognostic factors.

RESULTS

Multivariate Cox proportional hazard regression analyses of factors affecting the all-cause mortality and GIST-related mortality among US patients between 2010 and 2017 revealed a higher overall mortality in non-Hispanic Black patients (HR = 1.516, 95% CI 1.172-1.961, p = 0.002), patients aged 80+ (HR = 9.783, 95% CI 4.185-22.868, p = 0), followed by those aged 60-79 (HR = 3.408, 95% CI 1.488-7.807, p = 0.004); male patients (HR = 1.795, 95% CI 1.461-2.206, p < 0.001); patients with advanced disease with distant metastasis (HR = 3.865, 95% CI 2.977-5.019, p < 0.001), followed by cases with regional involvement via both direct extension and lymph node involvement (HR = 3.853, 95% CI 1.551-9.57, p = 0.004); and widowed patients (HR = 1.975, 95% CI 1.494-2.61, p < 0.001), followed by single patients (HR = 1.53, 95% CI 1.154-2.028, p = 0.003). The highest CSM was observed in the same groups, except widowed patients and patients aged 60-79. The highest CSM was also observed among patients that underwent chemotherapy (HR = 1.687, 95% CI 1.19-2.392, p = 0.003).

CONCLUSION

In this updated study on the outcomes of patients with GISTs, we found that non-Hispanic Black patients, male patients, and patients older than 60 years have a higher mortality with GISTs. Furthermore, patients who have received chemotherapy have a higher GIST-specific mortality, and married patients have a lower mortality. However, we do not know to what extent these independent prognostic factors interact with each other to influence mortality. This study paves the way for future studies addressing these interactions. The results of this study may help treating clinicians to identify patient populations associated with a dismal prognosis, as those may require closer follow-up and more intensive therapy; furthermore, with married patients having a better survival rate, we hope to encourage clinicians to involve family members of the affected patients early in the disease course, as the social support might impact the prognosis.

2023 GEIS Guidelines for gastrointestinal stromal tumors

Gastrointestinal stromal tumor (GIST) is the most common malignant neoplasm of mesenchymal origin. GIST spans a wide clinical spectrum that ranges from tumors with essentially no metastatic potential to malignant and life-threatening spread diseases. Gain-of-function mutations in KIT or PDGFRA receptor tyrosine kinases are the crucial drivers of most GISTs, responsible for tumor initiation and evolution throughout the entire course of the disease. The introduction of tyrosine kinase inhibitors targeting these receptors has substantially improved the outcomes in this formerly chemoresistant cancer. As of today, five agents hold regulatory approval for the treatment of GIST: imatinib, sunitinib, regorafenib, ripretinib, and avapritinib. This, in turn, represents a success for a rare neoplasm. During the past two decades, GIST has become a paradigmatic model in cancer for multidisciplinary work, given the disease-specific particularities regarding tumor biology and tumor evolution. Herein, we review currently available evidence for the management of GIST. This clinical practice guideline has been developed by a multidisciplinary expert panel (oncologist, pathologist, surgeon, molecular biologist, radiologist, and representative of patients' advocacy groups) from the Spanish Group for Sarcoma Research, and it is conceived to provide, from a critical perspective, the standard approach for diagnosis, treatment, and follow-up.

Relationship between multi-slice computed tomography features and pathological risk stratification assessment in gastric gastrointestinal stromal tumors

BACKGROUND

Computed tomography (CT) imaging features are associated with risk stratification of gastric gastrointestinal stromal tumors (GISTs).

AIM

To determine the multi-slice CT imaging features for predicting risk stratification in patients with primary gastric GISTs.

METHODS

The clinicopathological and CT imaging data for 147 patients with histologically confirmed primary gastric GISTs were retrospectively analyzed. All patients had received dynamic contrast-enhanced CT (CECT) followed by surgical resection. According to the modified National Institutes of Health criteria, 147 lesions were classified into the low malignant potential group (very low and low risk; 101 lesions) and high malignant potential group (medium and high-risk; 46 lesions). The association between malignant potential and CT characteristic features (including tumor location, size, growth pattern, contour, ulceration, cystic degeneration or necrosis, calcification within the tumor, lymphadenopathy, enhancement patterns, unenhanced CT and CECT attenuation value, and enhancement degree) was analyzed using univariate analysis. Multivariate logistic regression analysis was performed to identify significant predictors of high malignant potential. The receiver operating curve (ROC) was used to evaluate the predictive value of tumor size and the multinomial logistic regression model for risk classification.

RESULTS

There were 46 patients with high malignant potential and 101 with low-malignant potential gastric GISTs. Univariate analysis showed no significant differences in age, gender, tumor location, calcification, unenhanced CT and CECT attenuation values, and enhancement degree between the two groups (P > 0.05). However, a significant difference was observed in tumor size (3.14 ± 0.94 vs 6.63 ± 3.26 cm, P < 0.001) between the low-grade and high-grade groups. The univariate analysis further revealed that CT imaging features, including tumor contours, lesion growth patterns, ulceration, cystic degeneration or necrosis, lymphadenopathy, and contrast enhancement patterns, were associated with risk stratification (P < 0.05). According to binary logistic regression analysis, tumor size [P < 0.001; odds ratio (OR) = 26.448; 95% confidence interval (CI): 4.854-144.099)], contours (P = 0.028; OR = 7.750; 95%CI: 1.253-47.955), and mixed growth pattern (P = 0.046; OR = 4.740; 95%CI: 1.029-21.828) were independent predictors for risk stratification of gastric GISTs. ROC curve analysis for the multinomial logistic regression model and tumor size to differentiate high-malignant potential from low-malignant potential GISTs achieved a maximum area under the curve of 0.919 (95%CI: 0.863-0.975) and 0.940 (95%CI: 0.893-0.986), respectively. The tumor size cutoff value between the low and high malignant potential groups was 4.05 cm, and the sensitivity and specificity were 93.5% and 84.2%, respectively.

CONCLUSION

CT features, including tumor size, growth patterns, and lesion contours, were predictors of malignant potential for primary gastric GISTs.

Clinical outcomes of endoscopic resection for the treatment of esophageal gastrointestinal stromal tumors: a ten-year experience from a large tertiary center in China

BACKGROUNDS

Esophageal gastrointestinal stromal tumors (E-GISTs) are extremely rare and surgical resection is the recommended approach. However, surgical resection usually causes severe trauma that may result in significant postoperative morbidity. Endoscopic resection (ER) has developed rapidly in recent years and has been widely used in gastrointestinal lesions. Nevertheless, the feasibility and efficacy of ER in the management of E-GISTs are unknown.

METHODS

Retrospective data were collected from January 2011 to December 2020 in a large tertiary center of China. Twenty-eight patients with E-GISTs treated by ER were included in the study.

RESULTS

Of the 28 patients, there were 21 males and 7 females, with a median age of 55 years (40-70 years). The median tumor size was 15 mm (5-80 mm). The technical success rate was 100% (28/28), while the en bloc resection rate was 96.4% (27/28). The median operation time was 35 min (10-410 min). Sixteen (57.2%) tumors were categorized into very low risk group, six (21.4%) into low risk group, and six (21.4%) into high risk group. Pathologists carefully examined margins of each lesion. There were 11 lesions (39.3%) determined as R0 resection and 17 lesions (60.7%) as R1 resection with positive margins. The median hospital stay was 2 days (range, 1-8 days). One patient suffered from hydrothorax and required drainage, leading to a major adverse event rate of 3.6% (1/28). There was no conversion to surgery, and no death occurred within 30 days after the procedure. Imatinib was given to two patients after ER under multidisciplinary team surveillance. During follow-up (median of 54 months, 9-122 months), no recurrences or metastasis were observed.

CONCLUSION

ER is safe and effective for E-GISTs and might become an optional choice in the future. Multicenter, prospective, large samples with long-term follow-up studies are still needed.

Counting mitoses in gastrointestinal stromal tumours (GISTs): variable practices in the real-world setting and their clinical implications

Mitotic count (MC) is an important prognostic indicator in gastrointestinal stromal tumours (GISTs). Though MC evaluation was initially proposed in 50 HPFs, recent international guidelines recommend that MC be performed on 5 mm² because HPFs may have different areas depending on the ocular field number (FN) of the utilized light microscope. Performing MC on different areas leads to a non-standardized evaluation and erroneous risk stratification. The aim of the study was to audit real-life MC practices with special emphasis on possible risk stratification errors. A survey was administered to Italian pathologists to evaluate the following: method used for MC (5 mm² versus 50 HPF); FN of the light microscope; prognostic scheme for risk stratification. Based on the results of the survey, 100 GISTs (25/risk class using Miettinen prognostic scheme) were retrieved and MC performed using 5 mm² versus the corresponding mm² area sizes of 50 HPFs with variable FNs (18, 20, 22). The survey demonstrated that the majority of pathologists (64.5%) use 50 HPFs with various FNs leading to excessive area size. The most frequently used prognostic scheme is that by Miettinen. Using this prognostic scheme and counting mitoses in 5 mm² versus 50 HPFs with FNs 18, 20 and 22, a change in risk class was identified ranging from 10 to 41%, depending on FN. In conclusion, this study demonstrates that MC is still frequently performed on 50 HPF, with area sizes exceeding the specified 5 mm² by far.

LAPAROSCOPIC VERSUS OPEN SURGERY IN GASTRIC GASTROINTESTINAL STROMAL TUMORS LARGER THAN 5 CM: A SYSTEMATIC REVIEW AND META-ANALYSIS

BACKGROUND

Surgical resection represents the main treatment for resectable nonmetastatic gastric gastrointestinal stromal tumors. Despite the feasibility and safety of laparoscopic resection, its standard use in gastric tumors larger than 5 cm is yet to be established.

AIMS

This study aimed to compare the current evidence on laparoscopic resection with the classical open surgical approach in terms of perioperative, postoperative, and oncological outcomes.

METHODS

The PubMed, Scopus, and Web of Science databases were consulted. Articles comparing the approach to gastric gastric gastrointestinal stromal tumors larger than 5 cm by open and laparoscopic surgery were eligible. A post hoc subgroup analysis based on the extent of the surgery was performed to evaluate the operative time, blood loss, and length of hospital stay.

RESULTS

A total of nine studies met the eligibility criteria. In the study, 246 patients undergoing laparoscopic surgery and 301 patients undergoing open surgery were included. The laparoscopic approach had statistically significant lower intraoperative blood loss (p=0.01) and time to oral intake (p<0.01), time to first flatus (p<0.01), and length of hospital stay (0.01), compared to the open surgery approach. No significant differences were found when operative time (0.25), postoperative complications (0.08), R0 resection (0.76), and recurrence rate (0.09) were evaluated. The comparative subgroup analysis between studies could not explain the substantial heterogeneity obtained in the respective outcomes.

CONCLUSION

The laparoscopic approach in gastric gastrointestinal stromal tumors larger than 5 cm compared to the open surgical approach is a technically safe and feasible surgical method with similar oncological results.

The value of contrast-enhanced harmonic endoscopic ultrasound in differential diagnosis and evaluation of malignant risk of gastrointestinal stromal tumors (<50mm)

OBJECTIVES

Contrast-enhanced harmonic endoscopic ultrasound (CEH-EUS) has been used in the differential diagnosis of benign and malignant tumors by visualization of tumor microcirculation and perfusion. However, its diagnostic role in submucosal tumors (SMTs), especially leiomyomas and gastric submucosal tumors (GISTs) was rarely studied. The aim of this study was to analyze the diagnostic role of CEH-EUS for SMTs (<50 mm) and the value of assessing the malignant potential of GISTs.

MATERIALS AND METHODS

We retrospectively included patients with tumors <50 mm in diameter who underwent preoperative EUS and CEH-EUS examination and had pathologically confirmed as leiomyomas and GISTs. To analyze the imaging features of CEH-EUS with pathological diagnosis as the gold standard and evaluate its diagnostic value.

RESULTS

This study included 10 cases of leiomyomas and 38 cases of GISTs. Under CEH-EUS detection, 86.9% of GISTs showed hyper-enhancement, 89.5% showed diffuse enhancement, 39.5% showed non-enhancing spots, and 97.4% showed obvious capsule enhancement. In contrast, the leiomyoma cases mostly showed hypo-enhancement (50.0%) or non-enhancement (30.0%) (p < 0.05). Then, the value of CEH-EUS in the differential diagnosis of benign and malignant tumors based on blood flow is significantly higher than that of B-EUS. Signal appearance time was significantly faster in the intermediate-high risk GISTs than in the very low-low risk group (5.1 s versus 15.5 s, p < 0.05), and the AUROC values predicted the risk at this time to be 0.903 (0.763-0.975). Heterogeneous perfusion and non-enhancing spots were also more common in the intermediate-high risk group. Univariate and multivariate analysis revealed that intratumoral irregularitie was an independent predictor of moderate to high risk (OR 3.99, 95%CI 1.04-90.95), with sensitivity, specificity and accuracy of 73.33%, 91.30% and 84.21%, respectively.

CONCLUSIONS

Through this study, CEH-EUS has a good differential diagnostic ability for leiomyomas and GISTs, and has a high value in predicting the risk of GISTs.

Schwannoma of the Ascending Colon in a 22-Year-Old Male: A Case Report

Schwannoma of the ascending colon is an extremely rare neoplasm that is often discovered incidentally in the asymptomatic older population on surveillance colonoscopy. We present the case of a symptomatic 22-year-old male presenting with one month of discomfort in the right lower abdominal quadrant, abdominal bloating, and hematochezia. A sessile polyp measuring 0.5 cm was identified in the ascending colon on the colonoscopy. The polyp was completely resected using cold snare polypectomy. Histological examination of the resected polyp with hematoxylin-eosin staining revealed small nodules of bland spindle cells with focal nuclear condensation. The lesional cells tested positive for S-100 and SOX-10 on immunohistochemical analysis, establishing the diagnosis of benign schwannoma. Since this lesion was submucosal, its diagnosis required an endoscopic biopsy that could only be performed on the mucosa. It was difficult to distinguish it from other mesenchymal tumors (gastrointestinal stromal tumor or leiomyoma), and this makes the differential diagnosis exceedingly challenging. If the immunohistochemistry is positive for S-100 and negative for C-KIT, CD-34, actin, and desmin, it aids in diagnosis. These tumors have non-specific radiological features and are asymptomatic.

Clinicopathological and therapeutic analysis of PDGFRA mutated gastrointestinal stromal tumor

BACKGROUND

Platelet-Derived Growth Factor Receptor Alpha (PDGFRA) mutation has causes a rare subgroup of gastrointestinal stromal tumor (GIST) and not too much attention has been paid on it until the appearance of Avapritinib. This study aims to explore the clinicopathological features, therapy and prognosis of PDGFRA-mutant GIST for better understanding and clinical practice.

METHOD

119 PDGFRA-mutant GIST patients were retrospectively collected from 2038 patients who underwent genetic testing. Kaplan-Meier method was used.

RESULTS

The incidence rate of PDGFRA-mutant GIST in our center was 5.8 %, with 79 males, 40 females, and a median age of 57 (25⁃80) years old. All the tumors were in the stomach, among which 60 were epithelioid type, 25 were spindle type and 34 were mixed type. There were 13 cases of exon 12 mutation and 106 cases of exon 18 mutation including 83 cases of D842V mutation (69.7 %). During a median follow⁃up of 49.6 (range, 1⁃154) months, progression could be observed in 12 patients with gene mutation at the codon 842 of exon 18, another case was V561D mutation in exon 12. The 5-year diseases⁃free survival (DFS) was 90.1 %, which was associated with the loss of CD34 expression (P＜0.001). Patients in D842V group showed a marginal worse prognosis than those in non-D842V group (P = 0.163). According to the NIH criteria, high risk group showed a poorer prognosis than non-high risk group (P = 0.003), however, there were no significant differences among the three non-high risk groups (P = 0.495, P = 0.652). Among 13 advanced patients, 5 cases (treated with Avapritinib) achieved partial remission.

CONCLUSION

PDGFRA-mutant GIST mostly derived from stomach, with a relative indolent behavior. D842V mutation and lose of CD34 expression were adverse prognostic factors. Avapritinib can effectively control advanced patients in a certain period of time.

GIST: Correlation of risk classifications and outcome

In clinical practice, there are often discrepancies between the oncological prognosis of gastrointestinal stromal tumors (GIST) and the actual clinical course. This study aimed to check with our collective how reliably the current classifications (Miettinen, Fletcher) predict the prognosis of GIST and to evaluate whether an extension of the classifications by the parameter proliferation activity could make sense. This prospective study enrolled 58 patients who underwent surgery on GIST from 01/2006 to 12/2016. The postoperative course (curation, recurrence, progress) was correlated with the identified risk classification and the proliferative activity. Coincidences with other tumors were strikingly common in patients with GIST (43%). Based on the risk group assignment of GIST, no assessment of the probability of the occurrence of second neoplasia could be derived. Individual patients were under- or over-graduated concerning the assessment of biological behavior based on the standard risk classifications. The inclusion of proliferative activity did not allow for a more precise predictive power - neither to the risk of recurrence and metastasis nor to the development of a second neoplasia. The study showed that there is currently no parameter or logarithm that reliably predicts the biological behavior of GIST. Due to the frequency of coincidence of second neoplasia and (rare) distant metastases, for everyday clinical practice, appropriate staging diagnostic and regular follow-up care should also be used for benign GIST.

The GIST of Advances in Treatment of Advanced Gastrointestinal Stromal Tumor

Gastrointestinal stromal tumor (GIST) is the most common malignant neoplasm of mesenchymal origin and a compelling clinical and biologic model for the rational development of molecularly targeted agents. This is because the majority of GISTs are driven by gain-of-function mutations in KIT or PDGFRA receptor tyrosine kinases. Specific GIST mutations circumscribe well-defined molecular subgroups that must be determined during the diagnostic work-up to guide clinical management, including therapeutic decisions. Surgery is the cornerstone treatment in localized disease and can also be clinically relevant in the metastatic setting. The correct combination and sequence of targeted agents and surgical procedures improves outcomes for patients with GIST and should be discussed individually within multidisciplinary expert teams. All currently approved agents for the treatment of GIST are based on orally available tyrosine kinase inhibitors targeting KIT and PDGFRA oncogenic activation. Although first-line imatinib achieves remarkable prolonged disease control, the benefit of subsequent lines of treatment is more modest. Novel therapeutic strategies focus on overcoming the heterogeneity of KIT or PDGFRA secondary mutations and providing more potent inhibition of specific challenging mutations. This article reviews the current understanding and treatment of GIST, with an emphasis on recent advances.

A Case of Metastatic Gastric Leiomyosarcoma With Bilateral Adrenal Involvement and Complications

Gastric leiomyosarcoma is a rare entity with only a handful of cases reported in the literature. Although this entity has been known to metastasize, there are currently no reported cases of metastatic leiomyosarcoma to the bilateral adrenal glands. We report a case of a 58-year-old woman with primary gastric leiomyosarcoma with bilateral metastasis to the adrenal gland. This case illustrates a presentation of gastric leiomyosarcoma with bilateral adrenal involvement, the challenges in its diagnosis, treatment, as well as a rare complication of primary adrenal insufficiency and adrenal crisis.

A Mass in the Thorax: A Rare Presentation of Gastrointestinal Stromal Tumor

Gastrointestinal stromal tumors (GIST) can occur anywhere in the gastrointestinal tract, with the primary site being the stomach. GISTs are often discovered incidentally on imaging due to the non-specific symptoms they present at the presentation. They can be distinguished from other mesenchymal tumors by immunohistochemistry staining. These tumors can range from benign to highly malignant, with surgical resection as the main treatment modality. Here, we present a case of a large GIST found not in the stomach, but in the mediastinum, incidentally on imaging, in a middle-aged male.

Differential Diagnosis and Molecular Stratification of Gastrointestinal Stromal Tumors on CT Images Using a Radiomics Approach

Treatment planning of gastrointestinal stromal tumors (GISTs) includes distinguishing GISTs from other intra-abdominal tumors and GISTs’ molecular analysis. The aim of this study was to evaluate radiomics for distinguishing GISTs from other intra-abdominal tumors, and in GISTs, predict the c-KIT, PDGFRA, BRAF mutational status, and mitotic index (MI). Patients diagnosed at the Erasmus MC between 2004 and 2017, with GIST or non-GIST intra-abdominal tumors and a contrast-enhanced venous-phase CT, were retrospectively included. Tumors were segmented, from which 564 image features were extracted. Prediction models were constructed using a combination of machine learning approaches. The evaluation was performed in a 100 × random-split cross-validation. Model performance was compared to that of three radiologists. One hundred twenty-five GISTs and 122 non-GISTs were included. The GIST vs. non-GIST radiomics model had a mean area under the curve (AUC) of 0.77. Three radiologists had an AUC of 0.69, 0.76, and 0.84, respectively. The radiomics model had an AUC of 0.52 for c-KIT, 0.56 for c-KIT exon 11, and 0.52 for the MI. The numbers of PDGFRA, BRAF, and other c-KIT mutations were too low for analysis. Our radiomics model was able to distinguish GISTs from non-GISTs with a performance similar to three radiologists, but less observer dependent. Therefore, it may aid in the early diagnosis of GIST, facilitating rapid referral to specialized treatment centers. As the model was not able to predict any genetic or molecular features, it cannot aid in treatment planning yet.

Extra gastrointestinal stromal tumor in the recto-vesical pouch: A case report and literature review

Introduction

Extra-gastrointestinal stromal tumors (EGISTs) are rare mesenchymal tumors located outside the gastrointestinal tract, and exhibit the same phenotypic and morphological profile of gastrointestinal stromal tumors (GISTs).

Case report

We report the case of a 20-year-old male patient consulted for chronic discomfort in the hypogastric region. Abdominal ultrasound and abdomino-pelvic CT scan identified a retro-vesical mass measuring 16 × 9 cm. He underwent an exploratory laparotomy and a total resection of the mass R0. The histopathological panel of the surgical specimen confirmed the diagnosis of EGIST.

Clinical discussion

The primary localization in the recto-vesical pouch of EGIST is a very rare entity. Their clinical and radiological presentations are unusual, and their definitive diagnosis is largely based on immunohistochemistry staining.

Conclusion

the origin of extra gastrointestinal stromal tumors EGIST can remain unclear.

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Extra gastrointestinal stromal tumors (EGISTs) are very rare primary entities that develop outside the digestive tract.

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Their primary localization in the recto-vesical pouch is a very rare entity.

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Their definitive diagnosis is largely based on immunohistochemistry staining.

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The only accepted treatment for non-metastatic EGISTs is a complete surgical resection.

Transvaginal Excision of Rectal Gastrointestinal Stromal Tumor: A Safe Minimally Invasive Approach

Introduction: Gastrointestinal stromal tumors (GISTs), the specific kit-positive mesenchymal tumors, are rarely found in the anorectum and account for 5% of all GIST cases. Surgical excision remains the main treatment for anorectal GIST. The available techniques include enucleation transanal excision or sometimes an abdominoperineal resection for large or low tumors. Case Study: We present a middle-aged female with a complaint of intermittent rectal pain for 1 year. Diagnostic workup detected a mass in the rectovaginal septum. A transvaginal excision was performed. Final histopathology showed rectal GIST. On regular follow-up visits, there was no detectable recurrence, and her anal pain disappeared completely. Discussion: Colorectal GIST accounts for only 0.1% of all colorectal tumors; this infrequency has led to a controversy in its diagnosis and management. Nevertheless, surgery remains a cornerstone element in the management of rectal GISTs. Different resection methods have been described in the literature, ranging from less-invasive approach such as transanal excision to a more radical one like an abdominoperineal resection. As there is no standard approach, choosing which one to perform depends on the tumor size, its location, and the surgeon’s preference. Conclusion: Transvaginal excision could be considered a safe minimally invasive approach for low-lying rectal GISTs.

The occurrence of gastrointestinal stromal tumors with second malignancies - Case series of a single institution experience

INTRODUCTION

Gastrointestinal stromal tumors (GISTs) may coexist with different types of malignancies, either synchronously or metachronously. The aim of this study was to characterize the clinical and histopathological features of GIST coexisting with other neoplasms.

METHODS

A retrospective analysis of 76 GISTs cases diagnosed at our institution between January 2003 and March 2020 was performed. A subgroup of cases with concomitant second malignancy was selected. The clinical and pathologic records were reviewed.

RESULTS

18 out of 76 patients (23.7%) with GISTs were diagnosed with the second neoplasms. In 11 cases GISTs were diagnosed metachronously to the second malignancy, whereas 7 cases of GIST were synchronous. The most common concomitant neoplasms were breast cancer and gastric cancer. The concomitant GIST were located mainly in small intestine (52.6%). 14 GISTs were classified as very low or low-risk (77.8%), 3 as moderate risk (16.7%) and 1 as high risk tumors (5.6%).

CONCLUSION

The coexistence of GIST with other malignancies may be more common, than it has been considered. As the most of concomitant GISTs occurs metachronously to the second malignancy, studying of this phenomenon requires a long-term follow-up.

Fluorescent In Situ Hybridization Must be Preferred to pan-TRK Immunohistochemistry to Diagnose NTRK3-rearranged Gastrointestinal Stromal Tumors (GIST)

Tyrosine kinase inhibitors have revolutionized the treatment of patients with gastrointestinal stromal tumors (GISTs). Nevertheless, some GISTs do not contain any targetable KIT or PDGFRA mutations classically encountered in this field. Novel approved therapies targeting TRK chimeric proteins products of NTRK genes fusions consist in a promising approach to treat some patients with GISTs lacking any identified driver oncogenic mutation in KIT, PDGFRA or BRAF genes. Thus, an adequate testing strategy permitting to diagnose the rare NTRK-rearranged GISTs is required. In this work, we studied about the performances of pan-TRK immunohistochemistry (IHC) and NTRK1/2/3 fluorescent in situ hybridization in a series of 39 GISTs samples. Among 22 patients with GISTs lacking KIT or PDGFRA mutations, BRAFV600E IHC permitted to diagnose 2/22 (9%) BRAFV600E-mutated GISTs and, among the 20 KIT, PDGFRA, and BRAF wild type tumors, 1/20 (5%), NTRK3-rearranged tumor was diagnosed using NTRK3 fluorescent in situ hybridization. Pan-TRK IHC using EPR17341 and A7H6R clones was negative in this NTRK3-rearranged sample. Pan-TRK IHC was frequently positive in NTRK not rearranged tumors without (24 samples analyzed) or with (15 samples analyzed) KIT or PDGFRA mutations with major discrepancies between the 2 IHC clones (intraclass correlation coefficient of 0.3042). Given the new therapeutic opportunity offered by anti-TRK targeted therapies to treat patients with advanced cancers including GISTs, it is worth to extend molecular analysis to NTRK fusions testing in KIT, PDGFRA, and BRAF wild type GISTs. Pan-TRK IHC appears not relevant in this field but performing a simple NTRK3 fluorescent in situ hybridization test consists in a valuable approach to identify the rare NTRK3-rearranged GISTs treatable using anti-TRK therapies.

Gastrointestinal Stromal Tumors-A Mini Review

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. They are potentially malignant, and have an unpredictable evolution. The origin of these tumors is in the interstitial cells of Cajal, which are cells that are interposed between the intramural neurons and the smooth muscle cells of the digestive tract. GISTs are characterized by mutations in the gene c-Kit, but also other mutations, such as those of the platelet-derived growth factor receptor alpha. The most common locations of these tumors are the stomach and small intestine, although they can occur at any level of the digestive tract and occasionally in the omentum, mesentery and peritoneum. Most cases of GISTs are sporadic, and about 5% of cases are part of family genetic syndromes. The correct diagnosis of GIST is determined by histopathological examination and immunohistochemistry. According to histopathology, there are three main types of GISTs: spindle cell type, epithelioid type and mixed type. The therapeutic management of GIST includes surgery, endoscopic treatment and chemotherapy. The prognosis of patients with GIST varies depending on a number of factors, such as risk category, GIST stage, treatment applied and recurrence after treatment.

Coexistence of gastric cancer and gastric GIST with intra-tumor bleeding: successful embolization with subsequent total gastrectomy

Background

Gastrointestinal stromal tumor (GIST) is a rare tumor, however, simultaneous development of gastric cancer and gastric GIST has been documented more frequently in recent years. Rupture of gastric GIST is even more rare and occurred in 7% of all GISTs. Although ruptured GIST might be occasionally difficult to be managed by endoscopy, transcatheter arterial embolization (TAE) was reported to control bleeding from GIST effectively. We report herein a case of coexistence of gastric cancer and gastric GIST with progressing intra-tumor bleeding managed successfully by TAE and review the clinicopathological characteristics of this rare condition reported previously in the Japanese literature.

Case presentation

A 75-year-old woman with dyspnea and systemic edema was diagnosed as simultaneous occurrence of gastric cancer (histopathologically detected tubular adenocarcinoma pT2N1M0 fStageIIA) and gastric GIST (65 × 92 mm in diameter at the anterior wall of the fornix) with intra-tumor hemorrhage. Perceiving the progress of bleeding from tumor growth and exacerbating anemia, TAE of left gastric artery was performed. Then remission of anemia has been obtained, the patient underwent an elective radical surgery.

Conclusions

Simultaneous occurrence of gastric cancer and gastric GIST was speculated to be more common. TAE for ruptured GIST may be effective for hemostasis and reduction of tumor burden, which could facilitate minimal invasive surgery.

Efficacy and safety of endoscopic resection in treatment of small gastric stromal tumors: A state-of-the-art review

Gastrointestinal stromal tumors can occur in any part of the gastrointestinal tract, but gastric stromal tumors (GSTs) are the most common. All GSTs have the potential to become malignant, and these can be divided into four different grades by risk from low to high: Very low risk, low risk, medium risk, and high risk. Current guidelines all recommend early complete excision of GSTs larger than 2 cm in diameter. However, it is not clear whether small GSTs (sGSTs, i.e., those smaller than 2 cm in diameter) should be treated as early as possible. The National Comprehensive Cancer Network recommends that endoscopic ultrasonography-guided (EUS-guided) fine-needle aspiration biopsy and imaging (computed tomography or magnetic-resonance imaging) be used to assess cancer risk for sGSTs detected by gastroscopy to determine treatment. When EUS indicates a higher risk of tumor, surgical resection is recommended. There are some questions on whether sGSTs also require early treatment. Many studies have shown that endoscopic treatment of GSTs with diameters of 2-5 cm is very effective. We here address whether endoscopic therapy is also suitable for sGSTs. In this paper, we try to explain three questions: (1) Does sGST require treatment? (2) Is digestive endoscopy a safe and effective means of treating sGST? and (3) When sGSTs are at different sites and depths, which endoscopic treatment method is more suitable?

Curative intent treatment of late presented extragastrointestinal stromal tumor: two identical case reports with literature review

Gastrointestinal stromal tumors (GISTs) occurring outside the gastrointestinal tract are known as extragastrointestinal stromal tumors (EGIST). They share some common histopathologic and molecular characteristics. This report describes two female patients who were suspected of having a mesenteric GIST, but opted for surveillance rather than definitive treatment. Upon reassessment, both patients demonstrated increased tumor mass with no evidence of distant metastasis. The intraoperative findings confirmed the conclusion of clinical and imaging studies performed preoperatively and radical excisions were performed. Histopathological examination (spindle cell neoplasm) and immunohistochemistry (CD117) confirmed EGIST. Both patients underwent Imatinib therapy following surgery with no evidence of disease recurrence or metastasis upon follow up. Although sharing histologic features with GIST, EGIST frequently demonstrates distinct characteristics that facilitate the proper diagnosis and management of EGIST. Since it is a rare and aggressive disease with a poor outcome, early detection and curative surgical resection remains the mainstay of treatment.

The Mechanisms for the Association of Cancer and Esophageal Dysmotility Disorders

BACKGROUND

Achalasia and other esophageal dysmotility disorders mimicking achalasia can be associated with cancer. This study aimed to review the main mechanisms for which cancer may develop in esophageal dysmotility disorder patients.

METHODS

A narrative review was performed.

RESULTS

The mechanism for developing squamous cell carcinoma and adenocarcinoma are discussed. Besides, achalasia-like syndromes related to familial KIT-gene mutation and pseudoachalasia are discussed.

CONCLUSIONS

Knowing the main mechanism for which achalasia can be related to cancer is essential for clinicians to conduct the proper investigation, surveillance, and treatment.

Exploring the predictive value of additional peritumoral regions based on deep learning and radiomics: A multicenter study

PURPOSE

The present study assessed the predictive value of peritumoral regions on three tumor tasks, and further explored the influence of peritumors with different sizes.

METHODS

We retrospectively collected 333 samples of gastrointestinal stromal tumors from the Second Affiliated Hospital of Zhejiang University School of Medicine, and 183 samples of gastrointestinal stromal tumors from Tianjin Medical University Cancer Hospital. We also collected 211 samples of laryngeal carcinoma and 233 samples of nasopharyngeal carcinoma from the First Affiliated Hospital of Jinan University. The tasks of three tumor datasets were risk assessment (gastrointestinal stromal tumor), T3/T4 staging prediction (laryngeal carcinoma), and distant metastasis prediction (nasopharyngeal carcinoma), respectively. First, deep learning and radiomics were respectively used to construct peritumoral models, to study whether the peritumor had predictive value on three tumor datasets. Furthermore, we defined different sizes peritumors including fixed size (not considering tumor size) and adaptive size (according to average tumor radius) to explore the influence of peritumor of different sizes and types of tumors. Finally, we visualized the deep learning and radiomic models to observe the influence of the peritumor in three datasets.

RESULTS

The performance of intra-peritumors are better than intratumors alone in three datasets. Specifically, the comparisons of area under receiver operating characteristic curve in the testing set between intra-peritumoral and intratumoral models are: 0.908 vs 0.873 (P value: 0.037) in gastrointestinal stromal tumor datasets, 0.796 vs 0.756 (P value: 0.188) in laryngeal carcinoma datasets and 0.660 vs 0.579 (P value: 0.431) in nasopharyngeal carcinoma datasets. Furthermore, for gastrointestinal stromal tumor datasets, deep learning is more stable to learn peritumors with both fixed and adaptive size than radiomics. For laryngeal carcinoma datasets, the intra-peritumoral radiomic model could make model performance more balanced. For nasopharyngeal carcinoma datasets, radiomics is also more suitable for modeling peritumors than deep learning. The size of the peritumor is critical in this task, and only the performance of 1.5 mm-4.5 mm peritumors is stable.

CONCLUSIONS

Our results indicate that peritumors have additional predictive value in three tumor datasets through deep learning or radiomics. The definitions of the peritumoral region and artificial intelligence method also have great influence on the performance of the peritumor.

Establishment and Verification of a Nomogram for Predicting Survival in Patients with Small Intestinal Gastrointestinal Stromal Tumors

BACKGROUND

This study aimed to develop and validate nomograms for predicting overall survival (OS) and cancer-specific survival (CSS) in small intestinal gastrointestinal stromal tumors (SI GISTs).

METHODS

Patients diagnosed with SI GISTs were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database and further randomly divided into training and validating cohorts. Univariate and multivariate Cox analyses were conducted in the training set to determine independent prognostic factors to build nomograms for predicting 3- and 5-year OS and CSS. The performance of the nomograms was assessed by using the concordance index (C-index), calibration plot, and the area under the receiver operating characteristic curve (AUC).

RESULTS

Data of a total of 776 patients with SI GISTs were retrospectively collected from the SEER database. The OS nomogram was constructed based on age, surgery, imatinib treatment, and American Joint Committee for Cancer (AJCC) stage, while the CSS nomogram incorporated age, surgery, tumor grade, and AJCC stage. In the training set, the C-index for the OS nomogram was 0.773 (95% confidence interval [95% CI]: 0.722-0.824) and for the CSS nomogram 0.806 (95% CI: 0.757-0.855). In the internal validation cohort, the C-index for the OS nomogram was 0.741, while for the CSS nomogram, it was 0.819. Well-corresponded calibration plots both in OS and CSS nomogram models were noticed. The comparisons of AUC values showed that the established nomograms exhibited superior discrimination power than the 7th Tumor-Node-Metastasis staging system.

CONCLUSION

Our nomogram can effectively predict 3- and 5-year OS and CSS in patients with SI GISTs, and its use can help improve the accuracy of personalized survival prediction and facilitate to provide constructive therapeutic suggestions.

Is There Pathological Uniformity between the Periphery and Center of a Gastrointestinal Stromal Tumor?

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors and have some malignant potential. Mitotic count is important for predicting the malignant potential of GISTs. Proper treatment of GISTs requires accurate pathological diagnosis. In general, endoscopic ultrasound-guided fine-needle aspiration and deep biopsy are used for pathological diagnosis of GIST before making decisions about surgery. This study sought to evaluate the pathological uniformity of gastric GISTs for mitotic index of the center and periphery of the GIST.

METHODS

We retrospectively reviewed the data of 37 gastric GIST patients who underwent wedge resection at Hanyang University Hospital. We used Armed Forces Institute of Pathology criteria to classify gastric GISTs. To determine the pathological uniformity of gastric GISTs, we compared GIST risk stratification between the center and periphery of GISTs.

RESULTS

The mean size of GISTs was 3.56 ± 2.10 cm. Three lesions were located in the antrum, 11 in the fundus, 9 in the cardia, and 14 in the body. The mean age of patients was 58.65 ± 9.44 years; 18 patients were male and 19 were female. Thirty-five patients (94.6%) showed the same level of risk stratification between the center and periphery of gastric GISTs, while two patients (5.4%) presented different levels of risk between the two sites. No significant difference in mitotic count was observed between the two sites (kappa value = 0.863; p = 0.001).

CONCLUSIONS

Mitotic index category (either more than five mitoses per high-power field or five or fewer mitoses per high-power field) of GISTs showed good concurrence between the center and periphery.

Update on Molecular Genetics of Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. The majority are sporadic, solitary tumors that harbor mutually exclusive KIT or PDGFRA gain-of-function mutations. The type of mutation in addition to risk stratification corresponds to the biological behavior of GIST and response to treatment. Up to 85% of pediatric GISTs and 10–15% of adult GISTs are devoid of these (KIT/PDGFRA) mutations and are referred to as wild-type GISTs (wt-GIST). It has been shown that these wt-GISTs are a heterogeneous tumor group with regard to their clinical behavior and molecular profile. Recent advances in molecular pathology helped to further sub-classify the so-called “wt-GISTs”. Based on their significant clinical and molecular heterogeneity, wt-GISTs are divided into a syndromic and a non-syndromic (sporadic) subgroup. Recently, the use of succinate dehydrogenase B (SDHB) by immunohistochemistry has been used to stratify GIST into an SDHB-retained and an SDHB-deficient group. In this review, we focus on GIST sub-classification based on clinicopathologic, and molecular findings and discuss the known and yet emerging prognostic and predictive genetic alterations. We also give insights into the limitations of targeted therapy and highlight the mechanisms of secondary resistance.

Single-cell transcriptome analysis revealed the heterogeneity and microenvironment of gastrointestinal stromal tumors

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the human gastrointestinal tract. In this study, we performed single-cell RNA sequencing (RNA-seq) on intra- and peri-tumor tissues from GIST patients with the aim of discovering the heterogeneity of tumor cells in GIST and their interactions with other cells. We found four predominating cell types in GIST tumor tissue, including T cells, macrophages, tumor cells, and NK cells. Tumor cells could be clustered into two groups: one was highly proliferating and associated with high risk of metastasis, the other seemed "resting" and associated with low risk. Their clinical relevance and prognostic values were confirmed by RNA-seq of 65 GIST samples. T cells were the largest cell type in our single-cell data. Two groups of CD8⁺ effector memory (EM) cells were in the highest clonal expansion and performed the highest cytotoxicity but were also the most exhausted among all T cells. A group of macrophages were found polarized to possess both M1 and M2 signatures, and increased along with tumor progression. Cell-to-cell interaction analysis revealed that adipose endothelial cells had high interactions with tumor cells to facilitate their progression. Macrophages were at the center of the tumor microenvironment, recruiting immune cells to the tumor site and having most interactions with both tumor and nontumor cells. In conclusion, we obtained an overview of the GIST microenvironment and revealed the heterogeneity of each cell type and their relevance to risk classifications, which provided a novel theoretical basis for learning and curing GISTs.

Clinicopathological characteristics and outcomes of gastrointestinal stromal tumors with high progranulin expression

BACKGROUND & AIMS

Progranulin (PGRN) is known to promote tumorigenesis and proliferation of several types of cancer cells. However, little is known about the clinicopathological features of patients with gastrointestinal stromal tumors (GISTs) with regard to PGRN expression.

METHODS

A retrospective analysis was performed on patients with GISTs who underwent curative surgical resection between 2007 and 2017. PGRN expression was evaluated by immunohistochemical (IHC) analysis and semi-quantitatively categorized (no expression, 0; weak, 1+; moderate, 2+; strong, 3+). Tumors with a staining intensity of 2+ or 3+ were considered high PGRN expression.

RESULTS

Fifty-four patients were analyzed; 31 patients (57%) were male. The median age at surgery was 60 years (range, 33-79), and the most common primary site was the stomach (67%). Thirty-five patients (65%) had spindle histology; 42 patients (78%) were separated as a high-risk group according to the modified National Institutes of Health (NIH) classification. High PGRN-expressing tumors were observed in 27 patients (50%), had more epithelioid/mixed histology (68% vs. 32%; p = 0.046), and KIT exon 11 mutations (76% vs. 24%; p = 0.037). Patients with high PGRN-expressing tumors had a worse recurrence-free survival (RFS) (36% of 5-year RFS) compared to those with low PGRN-expressing tumors (96%; p<0.001). Multivariate analysis showed that high PGRN expression and old age (>60 years) were independent prognostic factors for poor RFS.

CONCLUSIONS

High PGRN-expressing GISTs showed more epithelioid/mixed histology and KIT exon 11 mutations. PGRN overexpression was significantly associated with poor RFS in patients with GISTs who underwent curative resection.

Laparoscopic Local Resection through Subserosal Dissection with Endoscopic Air-Insufflation for Submucosal Tumors Located Near the Esophagogastric Junction

Purpose

A novel resection method, namely, laparoscopic local resection through subserosal dissection with endoscopic air-insuff lation (LRSDEA) was used for submucosal tumors located near the esophagogastric junction (SMT-EGJ) to avoid major gastric resection.

Methods

A total of 9 cases underwent LRSDEA. We sequentially performed: laparoscopic dissections around EGJ, subserosal dissections around SMTs using laparoscopic electrocautery and ultrasonic shears, and finally, enucleation of SMTs. During these procedures, intraoperative endoscopic tumor localization, as well as endoscopic air-insufflation allowed for safe resection. These procedures are shown in the supplementary video clip. The clinicopathological characteristics and surgical results were analyzed.

Results

All laparoscopic procedures were successfully performed without requiring a major gastrectomy. The mean operation time was 126.1 minutes, and estimated blood loss was 12.0 ml. There were no postoperative complications. Pathological diagnoses were 6 leiomyomas, 2 gastrointestinal stromal tumors, and 1 gastric duplication.

Conclusion

LRSDEA is an effective and safe treatment option for SMT-EGJ, as major resection of the stomach is avoided.

An unusual presentation of an extragastrointestinal stromal tumour: a case report

Background

Gastrointestinal stromal tumours (GISTs) account for most mesenchymal gastrointestinal tumours, which in turn represent 1% of all gastrointestinal cancers. They mainly affect older adults, with a slight male preponderance. These lesions can be found along the digestive tract and most frequently in the stomach. Extragastrointestinal stromal tumours (EGISTs) are even rarer lesions, with few cases or series reported.

Case presentation

A 51-year-old woman was referred to our hospital due to progressive abdominal volume increase. Evaluation by multidetector computed tomography (MDCT) revealed a large intraperitoneal mixed tumour with few solid components, measuring up to 30 cm and compressing the surrounding structures, thought to be an ovarian tumour. Diagnostic laparotomy showed that the lesion was adherent to the greater gastric curvature and the vesical peritoneum. The lesion was removed without complications.

Conclusions

Imaging plays an essential role in the diagnosis of large intraperitoneal tumours. MDCT is the preferred technique to stage and to follow-up EGISTs.

Gastrointestinal Applications of Iodine Quantification Using Dual-Energy CT: A Systematic Review

Dual-energy computed tomography (DECT) can estimate tissue vascularity and perfusion via iodine quantification. The aim of this systematic review was to outline current and emerging clinical applications of iodine quantification within the gastrointestinal tract using DECT. The search was conducted with three databases: EMBASE, Pubmed and The Cochrane Library. This identified 449 studies after duplicate removal. From a total of 570 selected studies, 30 studies were enrolled for the systematic review. The studies were categorized into four main topics: gastric tumors (12 studies), colorectal tumors (8 studies), Crohn’s disease (4 studies) and miscellaneous applications (6 studies). Findings included a significant difference in iodine concentration (IC) measurements in perigastric fat between T1–3 vs. T4 stage gastric cancer, poorly and well differentiated gastric and colorectal cancer, responders vs. non-responders following chemo- or chemoradiotherapy treatment among cancer patients, and a positive correlation between IC and Crohn’s disease activity. In conclusion, iodine quantification with DECT may be used preoperatively in cancer imaging as well as for monitoring treatment response. Future studies are warranted to evaluate the capabilities and limitations of DECT in splanchnic flow.

Evaluation of Ki67 Index in Endoscopic Ultrasound-Guided Fine Needle Aspiration Samples for the Assessment of Malignancy Risk in Gastric Gastrointestinal Stromal Tumors

BACKGROUND

The risk of malignancy in resected gastrointestinal stromal tumors (GISTs) depends on tumor size, location, and mitotic index. Reportedly, the Ki67 index has a prognostic value in resected GISTs. We aimed to analyze the accuracy of endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) samples with reference to Ki67 index, using surgical specimens as the gold standard.

METHODS

Fifty-five patients who underwent EUS-FNA followed by surgical resection for gastric GISTs were retrospectively analyzed. Patients' age and sex; tumors' size and location; mitotic index, cell type, cellularity, pleomorphism, presence of ulceration, hemorrhage, necrosis, mucosal or serosal invasion, growth pattern, and Ki67 index based on pathology were investigated.

RESULTS

Location in fundus, ulceration, hemorrhage, mucosal invasion, and Ki67 index in surgical specimens were significant in predicting high-risk groups (p < 0.05) on univariate analysis. Frequency of bleeding (p = 0.034) and the Ki67 index (p = 0.018) were the only independent significant factors in multivariate analysis. The optimal cutoff level of Ki67 was 5%, with 88.2% sensitivity and 52.8% specificity (p = 0.021). The mean Ki67 index was lower in EUS-FNA samples than in surgical specimens (2% [1-15] versus 10% [1-70], p = 0.001). The rank correlation coefficient value of Ki67 was 0.199 (p = 0.362) between EUS-FNA and surgical samples and showed no reliability for EUS-FNA samples.

CONCLUSION

The Ki67 index in resected specimens correlated with high-risk GISTs, although it had no additive value to the current criteria. The Ki67 index in EUS-guided FNA samples is not a reliable marker of proliferation in GISTs.

Skin Metastasis of Gastrointestinal Stromal Tumors: A Case Series and Literature Review

Background

Gastrointestinal stromal tumors (GISTs) extremely and rarely metastasize to the skin, and such metastases have not been well characterized.

Methods

Retrospective analysis of clinicopathological data of patients with skin metastasis of a GIST (SM-GIST) admitted to Xiangya Hospital (Changsha, Hunan, China) and literature review were conducted.

Results

Including our 4 cases, a total of 17 cases have been reported to date. The mean age of the patients was 55.4 years (29~70 years) and there was not sex predominance (male 10 and female 7). Primary tumors were often located in the stomach (n=9), duodenum (n=2) and small bowel (n=2). Meanwhile, SM-GIST mainly occurred in head and face (n=6), extremities (n=6), followed by abdomen wall (n=5), back (n=3) and chest (n=2). Mutation analysis revealed that the frequency of wild-type GIST (WT-GIST), exon 9, 11 and 13 mutations was 6, 1, 4 and 1, respectively. The average time to SM-GIST was 4.22 years, specifically 4.59 years in gastric and 3.8 years in non-gastric. Moreover, for the resection only group (including chemotherapy), such average time was 3.63 years, while for the combined group (resection and tyrosine kinase inhibitors (TKIs)), it was about 4.74 years. The mean survival was approximately 6.2 years. However, after the diagnosis of SM-GIST, survival was only about 1.69 years.

Conclusion

SM-GIST is a rare malignant condition. Non-gastric GIST, surgery without TKIs, high invasiveness and tumor burden, and molecular subtype (mutation in exon 9, 11 and wild-type) may be conducive to the development of SM-GIST. Additionally, it is also a sign of poor prognosis.

Primary Gastrointestinal Stromal Tumor of the Prostate: Unexpected Guest

Primary mesenchymal lesions of the prostate are exceptionally rare. They comprise 1% of all prostatic neoplasms. Despite its rare location, the diagnosis of primary gastrointestinal stromal tumors (GISTs) of the prostate gland should never be missed. Such a diagnosis can be made after the rolling out of direct extension from adjacent organs, especially the rectum. GIST diagnosis has a clinical impact on patient treatment and clinical outcomes. They harbor a certain KIT activation mutation that responds to pharmacologic therapy inhibitors.

The objective of the current study was to provide a thorough review of GIST arising primarily in the prostate gland along with a comprehensive study of GIST pathogenesis, histologic morphology, immunohistochemistry, and molecular studies’ findings, and their importance in differentiating GIST from other prostate mesenchymal tumors. This will emphasize the role of careful spindle cell lesion diagnosis in the prostate gland that can influence the prognostic stratification of clinical management, future follow-up, and disease outcome.

Thirteen cases were collected after an extensive and detailed review of the English literature through PubMed, Medknow, Google Scholar, as well as personal experience.

The anatomic location of this lesion plays a significant role in the differential diagnosis. It is difficult to establish the accurate primary origin of GIST on core needle tissue biopsy. Thus, clinical, and radiological examinations play a crucial role in rolling out the possibility of rectal GIST secondarily invading and involving the prostate gland.

To conclude, primary prostatic GIST is a rare diagnosis. Extraintestinal, particularly rectal, GIST can clinically and radiologically mimic the impression of the prostatic lesion. Before diagnosing primary prostatic spindle cell lesions, such as solitary fibrous tumor (SFT), inflammatory myofibroblastic tumor (IMT), leiomyoma, leiomyosarcoma, or prostatic stromal tumors, one should include CD117/c-Kit in the workup of a prostatic spindle cell lesion. GIST has distinct pathogenesis, and its diagnosis can have a clinical impact on the patient's management plan and clinical outcome.