Gastrointestinal stromal tumors: review on morphology, molecular pathology, prognosis, and differential diagnosis

Selective internal radiation with Y-90 resin microspheres (SIRT) for liver metastases of gastro-intestinal stromal tumors (GIST) resistant to tyrosine kinase inhibitor (TKI) therapy

BACKGROUND

Hepatic metastases of GIST might be the dominant site of progression and resistant to available tyrosine kinase inhibitors (TKIs). Selective internal radiation therapy (SIRT) offers treatment by intratumoral radiation up to 200 Gy. We analyzed the hepatic progression-free survival (H-PFS) in a consecutive patient cohort.

METHODS

Twenty-six patients (median age 57.6 years) with biopsy proven liver metastases of GIST were treated by SIRT. All had RECIST documented tumor progression, and 24/26 patients had up to four lines of pretreatment. Mutational status was 'quadruple wildtype' (q-wt, n = 5), KIT exon 11/9/13 in n = 15/4/1 cases and PDGFRα (n = 1). Median follow-up of this retrospective analysis of a prospectively kept database is 33.6 months.

RESULTS

Median H-PFS was 16 months (range, 4-54+ months, 95% CI 6.5-25.4 months) and OS after SIRT was 28 months (95% CI 17.2-28.7 months). Best H-PFS was observed in patients with 'q-wt' at 25 months (range, 6+-54 months, 95% CI 16.2-33.8 months). The worst outcome was for KIT exon 11 mutations plus secondary mutations with 7 months (range, 4-33 months, 95% CI, 4.2-9.8 months).

CONCLUSIONS

90Y-SIRT is a potent treatment for patients with liver metastases of GIST resistant to TKI therapy. In patients with 'q-wt' GIST, SIRT is an option for first-line use.

Surgical resection for small (≤2 cm) gastric gastrointestinal stromal tumor

BACKGROUND

It is unclear whether surgical excision is the best course of treatment for small gastric gastrointestinal stromal tumor (GIST) ≤2 cm. The aim of this study was to evaluate the long-term survival results of surgical and non-surgical treatment for small gastric GIST.

METHODS

Between 2000 and 2021, patients with small gastric GIST were chosen from the Surveillance, Epidemiology, and End Results (SEER) database. Propensity score matching (PSM) was used to mitigate selection bias in the comparison process. Kaplan-Meier analysis and multivariate Cox model were used to assess the effects of demographic and clinical characteristics on overall survival (OS) and cancer-specific survival (CSS).

RESULTS

A total of 1229 patients with gastric GIST (≤2 cm) were included, including 1004 (81.69 %) patients who underwent operative management and 225 (18.31 %) who received non-operative management. The 5-year OS and CSS rates were compared between the two groups before PSM [5-year OS (83.51 % vs. 79.53 %, P < 0.001), 5-year CSS (96.96 % vs. 91.81 %, P = 0.017)]; after PSM [5-year OS (82.79 % vs. 80.00 %, P = 0.039), and 5-year CSS (94.88 % vs. 94.42 %, P = 0.398)]. Furthermore, after correcting for covariates, operative management was associated with a significant improvement in OS (HR = 0.62, 95 % CI 0.40-0.97, P = 0.037), while no significant effect on CSS was observed (HR = 0.85, 95 % CI 0.43-1.70, P = 0.643).

CONCLUSIONS

Our analysis demonstrated a statistically significant association between operative management and improved OS for small gastric GIST (≤2 cm).

Clinicopathological characteristics and long-term prognosis of peritoneal and retroperitoneal gastrointestinal stromal tumors

BACKGROUND

Peritoneal and retroperitoneal gastrointestinal stromal tumors (PRGISTs) are exceedingly uncommon, and their clinicopathological characteristics and long-term prognosis remain unreported. Therefore, our objective is to analyze these aspects of patients with PRGISTs using the Surveillance, Epidemiology, and End Results (SEER) database.

METHODS

Patients diagnosed with PRGISTs and small intestine stromal tumors (SISTs) between 2000 and 2019 were included in the study. Differences between groups were compared using Chi-square tests. Kaplan-Meier analysis and Cox proportional hazards models were used to evaluate overall survival (OS) and cancer-specific survival (CSS).

RESULTS

A total of 3817 patients were enrolled, with 3513 diagnosed with SISTs and 304 with PRGISTs. Compared to SISTs, PRGISTs patients were older, with larger tumors, higher mitotic rates, and greater risk of lymph node (5.3%) and distant (30.6%) metastasis (P < 0.001). Multivariate analysis identified N stage and mitotic rate as risk factors for distant metastasis in PRGISTs. In comparison to SISTs, PRGISTs patients exhibited a significantly worse OS (hazard ratio [HR] 1.83, 95% confidence interval [CI] 1.57-2.15, P < 0.001) and CSS (HR 2.11, 95% CI 1.73-2.58, P < 0.001). Subgroup analyses by age, sex, surgical status, chemotherapy, and marital status consistently demonstrated poorer OS and CSS for PRGISTs patients compared to SISTs patients (P < 0.05). The 1-, 3-, 5-, and 10-year OS rates for PRGISTs patients were 77.9%, 61.6%, 51.6%, and 32.8%, respectively, with corresponding CSS rates of 84.5%, 71.7%, 63.3%, and 49.0%. Multivariate Cox regression analysis identified age, race, surgical status, and mitotic rate as risk factors influencing OS, while race, surgical status, and mitotic rate were identified as risk factors affecting CSS.

CONCLUSIONS

In comparison to SISTs, PRGISTs patients exhibit distinct clinicopathological features and have a worse prognosis. However, surgical intervention can improve the prognosis of PRGISTs patients.

Endoscopic treatment outcome of oesophageal gastrointestinal stromal tumours

BACKGROUND

There are few clinicopathologic characteristics and clinical results for oesophageal gastrointestinal stromal tumours (GISTs). Thus, the objective of this study was to identify the clinicopathologic characteristics and clinical results of oesophageal GISTs.

AIM

To investigate endoscopic treatment effective of oesophageal GISTs.

METHODS

It was retrospective research that collected 32 patients with oesophageal GISTs treated by endoscopic resection (ER) between January 2012 and January 2023 in two Hospital. Clinicopathologic, endoscopic records, and follow-up data were collected and analysed.

RESULTS

Thirty-one patients underwent en bloc resection and 24 (75.0%) lesions underwent R0 resection. The size of GISTs was 2.12 ± 1.88 cm. The overall complication rate was 25.0%, including hydrothorax and post-endoscopic submucosal dissection electrocoagulation syndrome. The mean mitotic index was 3.34 ± 5.04 (median, 1.50; range, 1.00-4.00). Eighteen (56.3%), 6 (18.8%), 2 (6.3%), and 6 (18.8%) patients were identified as very low, low, intermediate, and high risk, respectively. Three patients developed recurrence after a median follow-up of 64.69 ± 33.13 months. The 5-year overall survival rate was 100%, and the disease-free survival rate was 90.6%.

CONCLUSION

ER is safe and effective for patients with low-risk oesophageal GISTs. Early detection of oesophageal GISTs is essential to achieve a favourable prognosis.

Study on the predictive value of preoperative CT features for the mitotic index of GIST based on the nomogram

This study aimed to construct a Nomogram based on preoperative CT features to predict the mitotic index in gastrointestinal stromal tumors and to establish preoperative risk stratification. The constructed nomogram prediction model is targeted towards guiding preoperative risk stratification, facilitating the provision of rational drug administration regimens, and tailoring appropriate surgical plans for personalized treatment. The imaging and pathological data of 250 patients with gastrointestinal stromal tumors in Shanxi Provincial hospital from January 2019 to January 2024 were retrospectively analyzed. According to the pathological data, the patients were divided into high mitotic index and low mitotic index, and were divided into a training group (n = 176) and a validation group (n = 74) according to a stratified sampling ratio of 7:3. In the training group, statistically significant variables were screened out by univariate analysis for multivariate logistic regression analysis, and independent risk factors were screened out and a Nomogram prediction model was constructed. The receiver operating characteristic (ROC) was used to evaluate the model discrimination, and the predicted probability risk was stratified by the optimal cutoff value. The Hosmer-Lemeshow test (HL test) was performed, and the calibration curve was drawn by Bootstrap repeated sampling 1000 times to evaluate the model consistency. Finally, the clinical application value of the prediction model was evaluated by the decision curve analysis (DCA). There were no significant differences in the distribution of clinical characteristics and CT features between the training group and the validation group ( P>0.05). Univariate analysis showed that the differences in tumor size, tumor site, boundary, calcification, liquefaction/necrosis, morphological characteristics, growth pattern, and ulceration were statistically significant (P<0.05). Multivariate logistic regression analysis screened out tumor size (GIST ≤ 2 cm, P = 0.018; GIST 2-5 cm, p = 0.009; GIST 5-10 cm, P = 0.017), liquefaction/necrosis (P = 0.002), and morphological characteristics (P = 0.002) as independent risk factors for high mitotic index. The Nomogram was established based on these three factors. The area under the curve (AUC) of the training group and the validation group of the model were 0.851 (95%CI: 0.793-0.91) and 0.836 (95%CI: 0.735-0.937), the specificity was 0.696 and 0.735, and the sensitivity was 0.869 and 0.760, respectively. The HL test had good calibration (training group P = 0.461, validation group P = 0.822), indicating that the predicted risk was consistent with the actual risk. The DCA also showed good clinical practicality. The Nomogram prediction model that incorporates preoperative CT features of tumor size, liquefaction/necrosis, and morphological characteristics can effectively predict the number of mitotic figures in gastrointestinal stromal tumors, and can perform effective preoperative risk stratification to guide clinical decision-making and personalized treatment.

Penile metastasis from a duodenal gastrointestinal stromal tumor: A rare case report

Penile metastases are rare, and metastasis of a gastrointestinal stromal tumor (GIST) to the penis is exceedingly uncommon. An 81-year-old man with a history of duodenal GIST, initially treated with curative resection and tyrosine kinase inhibitor therapy for liver metastasis, presented with an enlarging penile mass. A biopsy confirmed penile metastasis from GIST. To relieve his symptoms, a total penectomy was performed. Molecular testing revealed a KIT exon 9 mutation and CDKN2A/B gene alterations, indicating aggressive tumor behavior and resistance to standard treatment. This case underscores the importance of recognizing atypical metastatic sites in GIST.

Gastrointestinal Stromal Tumors

PURPOSE OF REVIEW

This review aims to outline the current understanding of the molecular drivers and treatment paradigms of gastrointestinal stromal tumors, with a focus on recent developments in treatment in the advanced disease setting.

RECENT FINDINGS

There have been recent advancements in our understanding of the molecular biology of gastrointestinal stromal tumors, including the identification of new genetic drivers and complex resistance mechanisms. We review the most recent findings in these areas, focusing on how new research insights are reshaping treatment strategies. Recent advancements in our understanding of the biology and treatment of GIST are paving the way for more personalized and effective therapeutic options. As knowledge of rare molecular subtypes, resistance mechanisms, and novel genomic techniques grows, new approaches are emerging in an effort to improve patient outcomes.

YAP acts as an independent prognostic marker and regulates growth and metastasis of gastrointestinal stromal tumors via FBXW7-YAP pathway

BACKGROUND

Although imatinib (IM) and subsequent tyrosine kinase inhibitors (TKIs) significantly improve the prognosis of GIST patients by delaying metastasis and recurrence, most patients experience limited efficacy due to toxicity and secondary resistance. We evaluated Yes-associated protein (YAP), a coactivator of the Hippo pathway accounting for IM resistance and aggressive GIST phenotypes, in GISTs. The degradation of YAP is mediated by FBXW7, and FBXW7 predicts recurrence and IM efficacy for GIST patients. Here, we aimed to identify the potential of YAP as a prognostic marker for patients with GISTs, and the molecular mechanism of FBXW7-YAP pathway in GIST cells.

METHODS

We measured YAP expression in 167 GIST cases using immunohistochemical staining, correlated its expression levels with clinicopathological features, and the molecular mechanism underlying the FBXW7-YAP pathway was further examined in vitro and in vivo.

RESULTS

Compared to 80 (47.9%) cases in the low YAP expression group, 87 (52.1%) cases with high YAP expression associated with a poorer prognosis in terms of overall survival (P = 0.004) and recurrence-free survival (P = 0.003). YAP expression was identified as a significant independent factor affecting the 5-year overall survival (P = 0.005) and recurrence-free survival rates (P = 0.007). Moreover, YAP was directly targeted by FBXW7 to affect proliferation, invasion, and migration in GIST cells. High YAP expression correlated with FBXW7 deficiency, as shown in xenograft and metastasis mouse models.

CONCLUSIONS

YAP expression serves as a predictive marker of recurrence for GIST patients with curative resection, highlighting its potential as a novel therapeutic target that warrants further investigation.

Clinical description and development of a prognostic score for neurofibromatosis type 1 (NF1)-associated GISTs: a retrospective study from the NETSARC

BACKGROUND

Gastrointestinal stromal tumors (GISTs) occur in ∼7% of neurofibromatosis type 1 (NF1) patients. Data about their natural history remain scarce and neither risk classifications, prognosis model nor adjuvant treatment have been validated in this population.

METHODS

This national retrospective study included consecutive operated NF1-GIST cases from 31 reference centers in France, mostly from the NETSARC+ network. Factors associated with relapse were used to build a new prognostic score (RECKGIST). To address potential bias between adjuvant group and follow-up group, a propensity score was used.

RESULTS

A total of 119 patients were included between 2008 and 2023, of whom 61% were women. Median age was 53 years (range 20-78 years). The main primary location was the small bowel (86%) and the stomach (11%). Median size and mitotic count (mit) were 45 mm [95% confidence interval (CI) 45-58 mm] and 2 mit/5 mm2 (95% CI 3-9 mit/5 mm2), respectively. The vast majority were KIT/PDGFRA wild type (mutation KIT 2%, PDGFRA 3%). The median follow-up was 6 years. For GISTs <30 mm (n = 35), none relapsed. For GISTS >30 mm (n = 84), 18 developed metastases (21%). There was no difference in relapse according to tumor location (P = 0.45) or tumor rupture (P = 0.11), whereas KIT/PDGFRA-mutated GISTs were at higher risk of relapse [recurrence-free survival (RFS) at 10 years of 30% versus 82.5% for wild type, P = 0.03]. Miettinen and Joensuu classification did not predict relapse accurately. For the RECKGIST score A (size ≤30 mm, n = 34) group, 10-year RFS was 100%; it was 78.5% in the RECKGIST B group (size >30 mm and 0 < mit ≤ 5, n = 60), and 45.5% in the RECKGIST C group (size >30 mm and mit >5, n = 20) (P < 0.0001). After matching, 10-year RFS was similar between adjuvant and surveillance groups (P = 0.34).

CONCLUSIONS

For NF1-GISTs <30 mm, prognosis without relapse is excellent. RECKGIST score accurately predicts recurrence and needs to be validated in an external cohort, but it may help treatment decision making. No efficacy of adjuvant treatment was observed.

Prognostic value of inflammatory markers in predicting recurrence-free survival in gastrointestinal stromal tumor patients: A nomogram-based approach

BACKGROUND

There are currently no relevant studies at home or abroad that combine inflammatory indicators and nomograms to predict the prognosis of gastrointestinal stromal tumor (GIST) patients after surgery. The purpose of this study was to investigate the predictive value of related inflammatory indicators [systemic immune-inflammation index (SII), neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR) and monocyte/Lymphocyte ratio (MLR)] in patients undergoing GIST surgery, incorporating relevant risk factors to establish a nomogram prediction model, with the aim of better predicting the prognosis of GIST patients.

AIM

To explore the relationships between the SII, NLR, PLR, and MLR and postoperative recurrence in patients with GIST.

METHODS

This study retrospectively included patients who underwent GIST surgery from January 2014 to January 2017 and analyzed the potential relationships between the preoperative SII, NLR, PLR, and MLR and clinicopathological features. The independent risk factors influencing the prognosis of GIST patients were obtained via multivariate regression analysis, and a nomogram model based on the independent risk factors was established.

RESULTS

Among the 124 GIST patients included in the present study, 31 (25%) experienced recurrence within 5 years. Kaplan-Meier survival analysis revealed a correlation between the MLR and PLR and tumor size (P = 0.016 and P = 0.002, respectively). The preoperative SII, MLR, NLR, and PLR were significantly associated with recurrence-free survival (RFS) (P < 0.05). The multivariate analysis results identified the PLR, MLR, and targeted therapy as independent prognostic factors for patient outcomes.

CONCLUSION

Preoperative MLR and PLR, which are independent risk factors for GIST recurrence, were correlated with RFS. Nomograms based on the PLR, MLR and targeted therapy can be used for clinical treatment.

Incidentally Discovered Duodenal Gastrointestinal Stromal Tumour (GIST): Operative Treatment and Problems After Surgery-A Case Report and Literature Review

Background: Gastrointestinal stromal tumours (GISTs) are mesenchymal tumours of the digestive tract that can involve any part of the tract. The tumours can be harmless or life-threatening. Materials and Methods: A case report of a surgeon who fell in a Finnish sauna, and he immediately felt that some ribs were broken. Magnetic resonance imaging and ultrasound showed three fractured ribs and an intrasplenic haematoma. Contrast-enhanced computed tomography (CT) demonstrated a small intrasplenic anomaly but no haematoma. Incidentally, an incidentaloma in the left adrenal gland was diagnosed. Three months later, a control CT scan was performed. The radiological findings on the adrenal gland and laboratory examinations matched those of a benign adenoma. Incidentally, a small duodenal tumour was diagnosed. At the same time, anaemia (haemoglobin: 104 g/L) and iron deficiency (ferritin: 8 μg/L) were noticed. An esophagogastroduodenoscopy showed an intramural tumour localised after the bulb-descending junction. Because the tumour was submucosal, the pathological diagnosis failed. Three months later, a radical surgical resection of the tumour with a resection margin of 2 mm and primary closing of the duodenum was performed. Pathological examination showed a well-circumscribed submucosal mesenchymal tumour with spindle cells. A tumour-free margin was uncertain. Immunohistochemistry findings showed a GIST. Due to the uncertain margin, an esophagogastroduodenoscopy control was planned at 2 years postoperatively. The patient disagreed with the decision and ordered a private control CT 3 months after the operation. The new CT found no local recurrence or metastasis. The patient contacted the head surgeon of the clinic, who ordered a 1-year postoperative CT. The 1-year follow-up CT finding agreed with the previous findings. Conclusion: The aftertreatment of a radical-operated GIST is extremely important if histologic examination of the tumour-free margin is uncertain. In that case, CT controls should be considered once a year for at least 3 years.

Primary Omental Leiomyosarcoma With Pulmonary Metastases: A Case Report of Surgical Management and Chemotherapy Response

Primary omental leiomyosarcoma is an extraordinarily rare tumor, with only a limited number of cases reported in the medical literature. Early surgical intervention appears to be a key determinant in the successful treatment of this malignancy, although more cases are needed to establish a standardized approach for optimal management. Leiomyosarcomas originating from the omentum present unique diagnostic challenges due to their rarity and often nonspecific clinical and radiologic findings. The complexities of diagnosing and managing this condition are compounded in rural areas where access to advanced diagnostic tools and specialists is limited. Leiomyosarcomas appear on abdominal computerized tomography (CT) as heterogeneous solid masses with cystic areas that enhance with contrast. While imaging can suggest the diagnosis, histopathology is required for confirmation. These tumors are highly aggressive, and complete surgical resection is the only definitive treatment, with resectability depending on peritoneal implants or metastasis. Other treatments, such as chemotherapy, radiation, and embolization, have variable success. Liver metastasis is the most common and a poor prognostic factor. Despite alternative therapies, surgery remains the best option for long-term survival. This case not only highlights the rarity and diagnostic challenges of omental leiomyosarcoma but also underscores the importance of timely referral to specialized centers. It further emphasizes the need for comprehensive diagnostic evaluations and personalized treatment plans tailored to the unique characteristics of each patient. Addressing these challenges through early intervention and targeted therapies is crucial to improving outcomes for patients with rare malignancies like omental leiomyosarcoma.

Radiological features of pancreatic desmoid-type fibromatosis: a case series and systematic review

PURPOSE

This retrospective study aimed to investigate the radiological features of pancreatic desmoid-type fibromatosis (PDF) and systematically review the previous publications and two new cases.

METHODS

We searched PubMed, Cochrane Library, and Web of Science Core Collection and included 31 patients with pathologically proven PDFs with analyzable preoperative computed tomography (CT) and magnetic resonance imaging, including two patients from our institution and 29 patients from 28 publications. Two board-certified radiologists reviewed all images.

RESULTS

The median age of the patients was 39 years, with a male dominance observed (male, 54.8% vs. female, 45.2%). Abdominal pain was the most frequent symptom, occurring in 58.1% of cases. Surgical resection was performed in all cases of PDFs, resulting in a recurrence rate of 8.3% (2/24). The tumors were most commonly located in the pancreatic tail (23/31, 74.2%). In terms of morphology, a "solid" shape was most prevalent (14/31, 45.2%), followed by a "solid and cystic" shape (9/31, 29.0%) and a "cystic" shape (8/31, 25.8%). Characteristic radiological features included heterogeneous enhancement of the solid portion of the tumors on CT scans (13/20, 65%), moderate-to-weak enhancement in the late phase on CT (16/17, 94.1%), and a presence of cystic components in the tumors (17/31, 54.8%). In 16.1% (5/31) of PDFs, the cystic component was pathologically confirmed to be a dilated pancreatic duct.

CONCLUSION

We summarized the clinical and imaging characteristics of PDF. Although the incidence may not be high, cystic components suggesting a dilated pancreatic duct within the tumor are unique imaging features in PDF.

Trends and Financial Burden of Gastrointestinal Stromal Tumors in the United States: A Comprehensive Analysis of United States Hospitalizations

Background

Gastrointestinal stromal tumors (GISTs) are associated with a substantial economic burden to the healthcare system despite their relatively low incidence and prevalence compared to other more common malignancies. This study aimed to evaluate trends in GIST-related hospitalizations, inpatient mortality, and the financial burden of GISTs in the United States.

Methods

The National Inpatient Sample (NIS) database from 2016 to 2020 was used to identify adult hospitalizations (age > 18 years) with a primary diagnosis of GIST. A multivariate logistic regression along with Chi-square and t-tests was performed using SAS 9.4 software to analyze inpatient GIST-associated mortality, inflation-adjusted total hospital charge (THC), and length of stay (LOS) during the study period.

Results

The study analyzed 48,690 hospitalizations (49.2% female, mean age 64.2 years, 38.2% elective admissions) with a primary diagnosis of GIST between 2016 and 2020. Annual GIST-related hospitalizations increased from 2,645 in 2016 to 11,565 in 2020 (P = 0.1208). The most common tumor location was stomach (48.5%), followed by small intestine (18.7%), large intestine (3.6%), and rectum (1.6%). There was a non-significant reduction in inpatient mortality from 4.16% in 2016 to 3.29% in 2020 (P = 0.807). Overall, 36.2% of patients had THC between $10,000 and $20,000 (36.5% in 2016 vs. 34.7% in 2020, P = 0.0001), and 9.8% of patients had a THC > $40,000 (8.3% in 2016 vs. 12.6% in 2020, P = 0.0001). Furthermore, 61.5% of patients had LOS of fewer than 5 days (59.16% in 2016 vs. 61.39% by 2020, P = 0.0001), and 38.5% had LOS of 5 days or more (40.84% in 2016 vs. 38.61% in 2020, P = 0.0001). The proportion of GISTs treated with endoscopic resection has remained stable with 13.02% in 2016 and 13.01% in 2020 (P = 0.08). Additionally, the proportion of surgical excisions decreased from 26.8% in 2016 to 21.4% in 2020 with a statistically significant trend (P = 0.004).

Conclusions

GIST-related inpatient mortality between 2016 and 2020 has remained stable, and endoscopic and surgical interventions have become more common for the management of GISTs. This has been accompanied by a significant rise in overall inflation-adjusted hospitalization costs in the study period. These findings highlight the need for continued optimization of care and resource allocation for GIST management.

Gastrointestinal stromal tumour (GIST): British Sarcoma Group clinical practice guidelines

BACKGROUND

British Sarcoma Group guidelines for the management of GIST were initially informed by those published by the European Society of Clinical Oncology. This update was written by a group of experts to includes a discussion of the highlight improvements in our knowledge of the disease and recent treatment developments. The guidelines include sections on Incidence, Aetiology, Diagnosis, including risk assessment, Treatment and Follow-up.

METHODS

A careful review of the literature was performed to ensure that wherever possible recommendations are supported by the results of clinical trials or substantive retrospective reports. Areas of uncertainty are indicated appropriately.

CONCLUSION

Guidelines represent a consensus view of current best clinical practice. Where appropriate, key recommendations are given and the levels of evidence and strength of recommendation gradings are those used by the European Society for Medical Oncology (ESMO).

Advances in the diagnosis and treatment of MET-variant digestive tract tumors

The receptor tyrosine kinase encoded by the MET gene plays an important role in various cellular processes such as growth, survival, migration and angiogenesis, and its abnormal activation is closely related to the occurrence and development of various tumors. This article reviews the recent advances in diagnosis and treatment of MET-variant digestive tract tumors. In terms of diagnosis, the application of next-generation sequencing technology and liquid biopsy technology makes the detection of MET variants more accurate and efficient, providing a reliable basis for individualized treatment. In terms of treatment, MET inhibitors such as crizotinib and cabotinib have shown good efficacy in clinical trials. In addition, the combination of immunotherapy and MET inhibitors also demonstrated potential synergies, further improving the therapeutic effect. However, the complexity and heterogeneity of drug resistance mechanisms are still one of the difficulties in current research. In the future, it is necessary to further deepen the understanding of the mechanism of MET variation and explore new combination treatment strategies to improve the overall survival rate and quality of life of patients. The diagnosis and treatment of MET-variant digestive tract tumors are moving towards precision and individualization, and have broad application prospects.

Multifocal Small Bowel Gastrointestinal Stromal Tumor (GIST): A Case Report

Gastrointestinal stromal tumours, also known as GIST, are a rare subset of soft tissue sarcomas. They are the most common mesenchymal neoplasms of the GI tract and can be found multifocal intra-operatively. We present a 44-year-old male patient who presented with vague upper abdominal pain of one-week duration associated with non-bilious vomiting. His CT abdomen with IV contrast revealed a non-enhancing intraperitoneal mass, which displaced the small bowel and mesentery; however, there was no obstruction or strangulation. A CT-guided biopsy was done and showed a low-grade gastrointestinal stromal tumor (GIST). Interestingly, during diagnostic laparoscopy, in addition to the large serosal ileal mass, he had multiple smaller lesions throughout the small bowel. He underwent resection of all the masses. He made an excellent recovery and was discharged home on postoperative day three. Small bowel GIST can rarely present as multiple lesions. Examination of all bowels during surgery is mandatory.

Gastrointestinal stromal tumors in fine-needle aspiration biopsies

Gastrointestinal stromal tumors (GISTs), although rare, are the most common mesenchymal neoplasms of the gastrointestinal tract. Their potential for malignancy underscores the significance of identifying them through cytomorphologic findings and pertinent immunohistochemical markers. GISTs can emerge anywhere along the gastrointestinal tract with a predilection for the stomach. The clinical manifestations vary from nonspecific abdominal symptoms to incidental discovery during diagnostic interventions for unrelated signs and symptoms. Cytologically, GIST aspirates contain spindle or epithelioid cells with immunoreactivity for CD117/c-KIT, DOG-1, and CD34. Molecularly, KIT or PDGFRA mutations are prevalent, guiding targeted therapy with tyrosine kinase inhibitors. Distinct subtypes like succinate dehydrogenase-deficient GISTs pose challenges, often affecting younger individuals and displaying unique features. Histologically, GISTs are graded by mitotic rates, aiding prognostication. Distinguishing GISTs from similar entities is pivotal, necessitating attention to their immunostaining patterns for making an accurate diagnosis and molecular alterations for effectively planning treatment. Common differential diagnoses include leiomyoma, schwannoma, and solitary fibrous tumor. This article presents a classic GIST case and showcases relatively simple diagnostic clues for identifying similar lesions that may occur in diverse locations.

Immune priming and induction of tertiary lymphoid structures in a cord-blood humanized mouse model of gastrointestinal stromal tumor

Gastrointestinal stromal tumors (GISTs) harbor diverse immune cell populations but so far immunotherapy in patients has been disappointing. Here, we established cord blood humanized mouse models of localized and disseminated GIST to explore the remodeling of the tumor environment for improved immunotherapy. Specifically, we assessed the ability of a cancer vascular targeting peptide (VTP) to bind to mouse and patient GIST angiogenic blood vessels and deliver the TNF superfamily member LIGHT (TNFS14) into tumors. LIGHT-VTP treatment of GIST in humanized mice improved vascular function and tumor oxygenation, which correlated with an overall increase in intratumoral human effector T cells. Concomitant with LIGHT-mediated vascular remodeling, we observed intratumoral high endothelial venules (HEVs) and tertiary lymphoid structures (TLS), which resemble spontaneous TLS found in GIST patients. Thus, by overcoming the limitations of immunodeficient xenograft models, we demonstrate the therapeutic feasibility of vascular targeting and immune priming in human GIST. Since TLS positively correlate with patient prognosis and improved response to immune checkpoint inhibition, vascular LIGHT targeting in GIST is a highly translatable approach to improve immunotherapeutic outcomes.

Gastrointestinal Stromal Tumors (GISTs) in Pediatric Patients: A Case Report and Literature Review

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms that primarily affect adults, with pediatric cases constituting only 0.5-2.7% of the total. Pediatric GISTs present unique clinical, genetic, and pathological features that distinguish them from adult cases. This literature review aims to elucidate these differences, emphasizing diagnostic and therapeutic challenges. We discuss the resistance of pediatric GISTs to conventional chemotherapy and highlight the importance of surgical intervention, especially in emergency situations involving intra-abdominal bleeding. The review also explores the molecular characteristics of pediatric GISTs, including rare mutations such as quadruple-negative wild-type GIST with an FGF3 gene gain mutation. To illustrate these points, we conclude with a case from our clinic involving a 15-year-old female with multiple CD117-positive gastric GISTs and a quadruple-negative wild-type genetic profile who required urgent surgical intervention following a failed tumor embolization. This case underscores the critical need for early diagnosis and individualized therapeutic strategies combining oncologic and surgical care to improve outcomes in pediatric GIST patients.

Insulin-like growth factor 2 targets IGF1R signaling transduction to facilitate metastasis and imatinib resistance in gastrointestinal stromal tumors

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are typical gastrointestinal tract neoplasms. Imatinib is the first-line therapy for GIST patients. Drug resistance limits the long-term effectiveness of imatinib. The regulatory effect of insulin-like growth factor 2 (IGF2) has been confirmed in various cancers and is related to resistance to chemotherapy and a worse prognosis.

AIM

To further investigate the mechanism of IGF2 specific to GISTs.

METHODS

IGF2 was screened and analyzed using Gene Expression Omnibus (GEO: GSE225819) data. After IGF2 knockdown or overexpression by transfection, the phenotypes (proliferation, migration, invasion, apoptosis) of GIST cells were characterized by cell counting kit 8, Transwell, and flow cytometry assays. We used western blotting to evaluate pathway-associated and epithelial-mesenchymal transition (EMT)-associated proteins. We injected transfected cells into nude mice to establish a tumor xenograft model and observed the occurrence and metastasis of GIST.

RESULTS

Data from the GEO indicated that IGF2 expression is high in GISTs, associated with liver metastasis, and closely related to drug resistance. GIST cells with high expression of IGF2 had increased proliferation and migration, invasiveness and EMT. Knockdown of IGF2 significantly inhibited those activities. In addition, OE-IGF2 promoted GIST metastasis in vivo in nude mice. IGF2 activated IGF1R signaling in GIST cells, and IGF2/IGF1R-mediated glycolysis was required for GIST with liver metastasis. GIST cells with IGF2 knockdown were sensitive to imatinib treatment when IGF2 overexpression significantly raised imatinib resistance. Moreover, 2-deoxy-D-glucose (a glycolysis inhibitor) treatment reversed IGF2 overexpression-mediated imatinib resistance in GISTs.

CONCLUSION

IGF2 targeting of IGF1R signaling inhibited metastasis and decreased imatinib resistance by driving glycolysis in GISTs.

Retroperitoneal schwannoma mimicking a metastatic lymph node of renal clear cell carcinoma: a case report

Schwannomas are usually benign tumors typically found in the head, neck, and extremities, with approximately 3% originating in the retroperitoneum. In this case, a young male presented with incidental masses in the left kidney and retroperitoneum. Abdominal pelvic enhanced computerized tomography (CT) revealed a tumor apparently originating from the left kidney, along with a retroperitoneal mass suspected to be a metastatic lymph node. Subsequently, a radical nephrectomy of the left kidney and retroperitoneal mass resection was performed. Pathological examination confirmed the left kidney mass as renal clear cell carcinoma and the retroperitoneal mass as schwannoma. The patient recovered uneventfully and was discharged from the hospital. A 6-month postoperative follow-up showed no evidence of recurrence. Preoperative diagnosis of schwannomas concurrent with other concurrent malignancies in rare sites, such as the retroperitoneum, is challenging due to their rare and non-specific radiological features. Although retroperitoneal schwannomas are rare, they should be considered in the differential diagnosis during CT examinations for renal cancer. Additionally, the advantages of a multidisciplinary team approach should be utilized in tumor management.

Pan-Canadian consensus recommendations for GIST management in high- and low-throughput centres across Canada

Gastrointestinal stromal tumours (GISTs) are mesenchymal tumours that originate from the interstitial cells of Cajal. GISTs are mainly driven by gain-of-function mutations in receptor tyrosine kinase or platelet-derived growth factor receptor alpha. Surgical resection is the only curative treatment for localized tumours and all currently approved medical GIST treatments are based on orally available tyrosine kinase inhibitors. Recent discoveries in the molecular and clinical features of GISTs have greatly impacted GIST management. Due to the provincially rather than nationally administered Canadian healthcare system, there have been inconsistencies in the treatment of GISTs across the country. Therefore, guidance on the latest knowledge, clinical management and treatment of GIST is needed to standardize the approach to GIST management nationwide. To establish pan-Canadian guidance, provide up-to-date data and harmonize the clinical practice of GIST management in high- and low-throughput centres across Canada; a panel of 20 physicians with extensive clinical experience in GIST management reviewed relevant literature. This included radiologists, pathologists, interventional radiologists, surgeons and medical oncologists across Canada. The structured literature focused on seven key domains: molecular profiling, radiological techniques/reporting, targeted localized therapy, intricacies of systemic treatments, emerging tests, multidisciplinary care and patient advocacy. This literature review, along with clinical expertise and opinion, was used to develop this concise and clinically relevant consensus paper to harmonize the knowledge and clinical practice on GIST management across Canada. The content presented here will help guide healthcare providers, especially in Canada, in terms of approaching and managing GIST.

Incidence and Survival Outcomes of Gastrointestinal Stromal Tumors

Importance

The incidence of gastrointestinal stromal tumors (GISTs) increased after the implementation of GIST-specific histology coding in 2001, but updated data on trends and survival are lacking.

Objective

To examine the evolving epidemiology of GISTs in major organ sites.

Design, Setting, and Participants

This descriptive, population-based cohort study used nationally representative data from the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) Program, including the SEER-22 and SEER-17 registries. Data were from evaluated patients aged 20 years or older with GISTs diagnosed between January 1, 2000, and December 31, 2019. Analyses were last updated on October 29, 2023.

Main Outcomes and Measures

Organ site-specific trends in age-standardized incidence rates and annual percent changes (APCs) in rates were estimated by race and ethnicity and, when possible, by sex, age, and primary indicator. Multivariable Cox proportional hazards regression models were used to examine racial and ethnic differences in overall and GIST-specific survival by site.

Results

The SEER-22 and SEER-17 datasets contained 23 001 and 12 109 case patients with GISTs, respectively. Patients in the SEER-22 registry had a mean (SD) age of 64 (13) years and 51.3% were men. With regard to race and ethnicity, 9.7% of patients were Asian or Pacific Islander, 12.3% were Hispanic, 19.6% were non-Hispanic Black, and 57.7% were non-Hispanic White. Overall incidence rates of GISTs in the SEER-22 cohort increased substantially over time for all organ sites but the colon (APCs: esophagus, 7.3% [95% CI, 4.4% to 10.2%]; gastric, 5.1% [95% CI, 4.2% to 6.1%]; small intestine, 2.7% [95% CI, 1.8% to 3.7%]; colon, -0.2% [95% CI, -1.3% to 0.9%]; and rectum, 1.9% [95% CI, 0.1% to 3.8%]). There were similar increasing trends by age groups (<50 vs ≥50 years), sex, race and ethnicity, and primary indicator for gastric and small intestine GISTs. Increases were mainly restricted to localized stage disease. Patients in the SEER-17 cohort had a mean (SD) age of 64 (14) years and 51.9% were men. With regard to race and ethnicity, 13.3% of patients were Asian or Pacific Islander, 11.6% were Hispanic, 17.8% were non-Hispanic Black, and 56.6% were non-Hispanic White. Non-Hispanic Black individuals had higher overall mortality for esophageal (adjusted hazard ratio [HR], 6.4 [95% CI, 2.0 to 20.3]) and gastric (adjusted HR, 1.4 [95% CI, 1.2 to 1.5]) GISTs compared with non-Hispanic White individuals. Asian or Pacific Islander individuals also had higher overall mortality for esophageal GISTs (adjusted HR, 5.6 [95% CI, 1.5 to 20.2]). Results were similar for GIST-specific survival.

Conclusions and Relevance

In this cohort study using SEER data, the incidence of GISTs in major organ sites increased in the last 2 decades among several population groups. These findings suggest that additional studies are warranted to identify risk factors, because histologic reclassification and higher availability of endoscopy and imaging do not fully explain these unfavorable incidence trends. Prevention efforts are needed to reduce the substantial survival disparities among racial and ethnic minoritized populations.

Gastrointestinal Stromal Tumor (GIST) Masquerading as a Pancreatic Pseudocyst: A Rare Case Report

Despite their relative rarity, gastrointestinal stromal tumors (GIST) are the most common type of mesenchymal tumor in the gastrointestinal (GI) tract. Here, we describe a rare case of a 62-year-old hypertensive female presenting with abdominal pain and a palpable mass, initially suspected to be a pancreatic pseudocyst based on radiological findings. Subsequent histopathological (HPE) examination following surgical resection revealed a large cystic lesion originating from the stomach, characterized as a malignant epithelioid GIST. Based on these findings and taking into consideration the symptomatology of the patient, the decision was made to post the patient for an upfront, open surgical exploration without pre-operative biopsy studies. Frozen section facilities were kept on standby considering the differential diagnosis. Since the frozen section revealed a gastric GIST, a decision was made to perform subtotal gastrectomy, followed by gastrojejunostomy (GJ) and jejunojejunostomy (JJ). In addition, the part of the cyst adherent to the left lobe of the liver was dealt with with a non-anatomical wedge resection. Immunohistochemical (IHC) analysis showed positivity for Cluster of Differentiation 117 (CD117) with negativity for Cluster of Differentiation 34 (CD34), Desmin, and Discovered On Gastrointestinal Stromal Tumors 1 (DOG-1). The tumor exhibited aggressive features, including high mitotic activity, i.e., >5/10 high power field (hpf), hemorrhagic areas, and infiltration into the liver parenchyma. The patient then received adjuvant imatinib-based chemotherapy and was maintained on strict follow-up.

Sex Cord-Stromal Tumors of the Ovary: An Update and Review. Part I - Pure Ovarian Stromal Tumors

In two separate reviews, we review the time-honored but still frequently challenging features of ovarian sex cord-stromal tumors, and also emphasize new developments including unusual morphologic appearances that, despite the relative rarity of many of the tumors, result in a disproportionate number of differential diagnostic problems, variant immunohistochemical profiles, and specific molecular and syndromic associations. These neoplasms are also of historical interest as current knowledge is still based in significant part on the contributions of 2 giants of gynecologic pathology, Dr Robert Meyer and Dr Robert E. Scully. In part I, we present the major clinical, pathologic, and genomic features of the pure ovarian stromal tumors including comments on differential diagnosis and briefly note significant historical contributions. In part II we will discuss pure sex cord and sex cord-stromal tumors.

A rare case of leiomyosarcoma with a pleomorphic component of the sigmoid colon

A 66-year-old man presented to our institution with a positive fecal occult blood test and lower abdominal pain. Although a tumor was found in the sigmoid colon, biopsy and imaging studies failed to enable the diagnosis of the cancer, and the patient underwent surgery for treatment and diagnosis. The tumor had two distinct areas with differing features shown both histopathologically and on imaging; it was thus diagnosed as a leiomyosarcoma of the sigmoid colon with a pleomorphic component. Here, we describe a rare case of leiomyosarcoma of the sigmoid colon with a pleomorphic component. There are no reports of leiomyosarcoma with pleomorphic components arising in the colon in the literature; thus, the recurrence and metastatic characteristics are unknown. Therefore, accumulating cases in the literature may provide valuable insights into diagnosing and treating these rare tumors.

Co-relation of gastrointestinal stromal tumors in a patient with leiomyoma cutis- A rare association

INTRODUCTION AND IMPORTANCE

Cutaneous leiomyomas, benign tumors from smooth muscle fibers, constitute about 5 % of all leiomyomas. They exhibit diverse inheritance patterns and can be linked to systemic malignancies. Gastrointestinal stromal tumors (GISTs), arising from the interstitial cells of Cajal, are the most common mesenchymal tumors in the gastrointestinal tract. Despite their prevalence, simultaneous occurrences of cutaneous leiomyomas and GISTs are rare, necessitating exploration of their potential relationship.

CASE PRESENTATION

A 25-year-old male with no significant medical history presented with multiple painful erythematous nodules on his chest, upper back, and arms. Histopathological analysis diagnosed these as multiple cutaneous piloleiomyomatosis. Despite recommendations for surgical intervention, the patient chose medical management and experienced significant pain relief with nifedipine. Later, the development of abdominal symptoms led to the discovery of multiple gastric lesions, diagnosed as benign spindle cell neoplasms, necessitating partial gastrectomy.

CLINICAL DISCUSSION

The differential diagnosis of cutaneous leiomyomas includes various soft tissue tumors, requiring histopathological confirmation. Genetic mutations affecting proteins critical to cellular energy production and tumor suppression underlie these conditions. Treatment options include pharmacological management and surgical excision. The discovery of GISTs in this patient aligns with rare literature reports, emphasizing the need for vigilant evaluation of systemic malignancies in patients with leiomyomatosis.

CONCLUSION

This case highlights the potential of cutaneous leiomyomas to indicate deeper malignancies like GISTs, stressing the importance of interdisciplinary collaboration in diagnosis and treatment. It underscores the interconnectedness of benign dermatological conditions and internal malignancies, advocating for comprehensive evaluation in patients with leiomyomatosis.

METHODS

This case report meticulously follows the SCARE 2023 guidelines: updating consensus Surgical Case Report guidelines (Sohrabi et al., 2023 [1]). These guidelines ensure high-quality reporting in surgical case reports. The report details the evaluation, diagnosis, and a comprehensive review of the literature pertaining to a patient with multiple leiomyoma cutis associated with gastrointestinal stromal tumors. By employing a multidisciplinary approach, this report achieves a thorough and standardized presentation of the case, serving as an additional tool for raising awareness regarding such rare conditions.

Gastrointestinal Stromal Tumors: A Retrospective Study at a Tertiary Care Center in Saudi Arabia in the Last Decade

INTRODUCTION

Gastrointestinal stromal tumors (GISTs) are a significant subset of mesenchymal tumors primarily found in the gastrointestinal tract, impacting diagnostic and therapeutic approaches. Understanding their epidemiology is crucial for improving patient care and advancing treatment strategies.

METHODOLOGY

Our study at a Saudi tertiary hospital analyzed 50 patients with GIST, focusing on demographics, tumor locations, and risk assessments. We examined predictors of tumor size, including mitosis frequency, and assessed the impact of anatomical location and risk on clinical outcomes using RStudio software (Posit, Boston, MA).

RESULTS

Among 50 patients with GIST, 36 (72.0%) were male with a median age of 60.5 years, and most tumors (33, 66.0%) were in the stomach. Risk assessments categorized tumors as follows: 20 (40.0%) low risk, 12 (24.0%) high risk, 7 (14.0%) moderate risk, 7 (14.0%) very low risk, and 4 (8.0%) no risk. Most tumors were low-grade (41, 82.0%) and nonmetastatic (47, 94.0%), predominantly spindle cell type (37, 74.0%). Tumor size varied significantly across risk categories: high-risk tumors averaged 10.3 cm versus 0.5 cm for no risk and 3.5 cm for very low risk (P < 0.001). Mitosis frequency differed significantly by risk category and tumor grade (P < 0.001). Tumor grade varied notably with risk categories and morphologic types, especially high-grade tumors in high-risk groups (8, 66.7%) and epithelioid tumors (2, 100%). Multivariable analysis identified predictors of tumor size: anatomical location (extra-GI, intra-abdominal; beta = 7.08, P = 0.011) and risk assessment (low risk, beta = 6.91, P = 0.001; moderate risk, beta = 11.2, P < 0.001; high risk, beta = 8.93, P < 0.001). Liver metastasis did not differ significantly across gender, anatomical location, risk assessment, or tumor grade.

CONCLUSIONS

In Saudi Arabia, GISTs predominantly affect males and are primarily located in the stomach. Our findings highlight significant variations in tumor size and grade based on risk assessments and anatomical location. Most GISTs were low-grade, nonmetastatic, and spindle cell type, emphasizing the need for enhanced research to improve diagnostics, tailor treatments, and optimize outcomes in the region.

Isolated Rectal Neurofibroma: A Case Report and Literature Review

Neurofibromas are considered benign peripheral nerve sheath tumors containing Schwann cells, fibroblasts, and perineurial cells. They are commonly associated with familial disorders. Isolated colonic neurofibromas are very rare. In this report, we discuss a case of a patient who presented to the gastroenterology clinic with a week-long occurrence of abdominal pain and bleeding. She underwent a colonoscopy in which three sentinel polyps of benign appearance, ranging in size from 4 mm to 10 mm, were removed during the procedure. The pathology report indicated that the distal rectal polyp contained a submucosal neurofibroma with SOX10+, desmin-, CD117-, DOG1-, CD34+. While NF1-associated neurofibromas harbor the risk of malignant transformation into malignant peripheral nerve sheath tumors (MPNSTs), the malignancy potential for isolated colonic neurofibromas remains uncertain due to their rarity. The clinical significance of isolated colonic neurofibromas is yet to be defined; therefore, the optimal management strategy remains uncertain. Close monitoring is advocated to both exclude the possibility of neurofibromatosis and be vigilant about the risk of malignant transformation.

A nomogram for predicting survival in patients with gastrointestinal stromal tumor: a study based on the surveillance, epidemiology, and end results database

PURPOSE

The objective of this investigation was to construct and validate a nomogram for prognosticating cancer-specific survival (CSS) in patients afflicted with gastrointestinal stromal tumor (GIST) at 3-, 5-, and 8-years post-diagnosis.

METHODS

Data pertaining to patients diagnosed with GIST were acquired from the Surveillance, Epidemiology, and End Results (SEER) database. Through random selection, a training cohort (70%) and a validation cohort (30%) were established from the patient population. Employing a backward stepwise Cox regression model, independent prognostic factors were identified. Subsequently, these factors were incorporated into the nomogram to forecast CSS rates at 3-, 5-, and 8-years following diagnosis. The nomogram's performance was assessed using indicators such as the consistency index (C-index), the area under the time-dependent receiver operating characteristic curve (AUC), the net reclassification improvement (NRI), the integrated discrimination improvement (IDI), calibration curves, and decision-curve analysis (DCA).

RESULTS

This investigation encompassed a cohort of 3,062 GIST patients. By analyzing the Cox regression model within the training cohort, nine prognostic factors were identified: age, sex, race, marital status, AJCC (American Joint Committee on Cancer) stage, surgical status, chemotherapy status, radiation status, and income status. The nomogram was subsequently developed and subjected to both internal and external validation. The nomogram exhibited favorable discrimination abilities, as evidenced by notably high C-indices and AUC values. Calibration curves confirmed the nomogram's reliability. Moreover, the nomogram outperformed the AJCC model, as demonstrated by enhanced NRI and IDI values. The DCA curves validated the clinical utility of the nomogram.

CONCLUSION

The present study has successfully constructed and validated the initial nomogram for predicting prognosis in GIST patients. The nomogram's performance and practicality suggest its potential utility in clinical settings. Nevertheless, further external validation is warranted.

Natural history of gastric leiomyoma

BACKGROUND

Most gastric leiomyomas are asymptomatic and benign subepithelial tumors (SETs); however, some may increase in size or become symptomatic. Understanding their natural history is therefore important to their management. We investigated the natural history of histologically proven gastric leiomyomas.

METHODS

We retrospectively reviewed histologically proven gastric leiomyoma cases at a tertiary center. The baseline characteristics of these cases were analyzed, and those with a follow-up period of at least 12 months without immediate resection were evaluated. The primary outcome was the frequency of size increase of more than 25% during the follow-up period, and the secondary outcome was the histopathologic results in cases that underwent resection.

RESULTS

Among the 231 patients with histologically proven gastric leiomyomas, the most frequent location was the cardia (77.1%), and the median size was 3 cm (IQR 2-4 cm). Eighty-four cases were followed up over a median period of 50.8 months (IQR 27.2-91.3 months). During the follow-up period, tumor size increased in two cases (2.4%). Surgical results showed that one case was leiomyoma, and the other was leiomyosarcoma. Among the remaining cases without change in size, 15 underwent surgical resection (n = 10) or endoscopic resection (n = 5), and all cases were confirmed as leiomyoma.

CONCLUSIONS

Most gastric leiomyomas are benign SETs, and an increase in size is not frequent, even in large-sized cases. Close monitoring with routine follow-up without resection may be sufficient in cases of histologically proven gastric leiomyoma. However, in cases of ulceration or size increase, resection may be beneficial.

Prediction of high Ki-67 proliferation index of gastrointestinal stromal tumors based on CT at non-contrast-enhanced and different contrast-enhanced phases

OBJECTIVES

To evaluate and analyze radiomics models based on non-contrast-enhanced computed tomography (CT) and different phases of contrast-enhanced CT in predicting Ki-67 proliferation index (PI) among patients with pathologically confirmed gastrointestinal stromal tumors (GISTs).

METHODS

A total of 383 patients with pathologically proven GIST were divided into a training set (n = 218, vendor 1) and 2 validation sets (n = 96, vendor 2; n = 69, vendors 3-5). Radiomics features extracted from the most recent non-contrast-enhanced and three contrast-enhanced CT scan prior to pathological examination. Random forest models were trained for each phase to predict tumors with high Ki-67 proliferation index (Ki-67>10%) and were evaluated using the area under the receiver operating characteristic curve (AUC) and other metrics on the validation sets.

RESULTS

Out of 107 radiomics features extracted from each phase of CT images, four were selected for analysis. The model trained using the non-contrast-enhanced phase achieved an AUC of 0.792 in the training set and 0.822 and 0.711 in the two validation sets, similar to models trained on different contrast-enhanced phases (p > 0.05). Several relevant features, including NGTDM Busyness and tumor size, remained predictive in non-contrast-enhanced and different contrast-enhanced images.

CONCLUSION

The results of this study indicate that a radiomics model based on non-contrast-enhanced CT matches that of models based on different phases of contrast-enhanced CT in predicting the Ki-67 PI of GIST. GIST may exhibit similar radiological patterns irrespective of the use of contrast agent, and such radiomics features may help quantify these patterns to predict Ki-67 PI of GISTs.

CLINICAL RELEVANCE STATEMENT

GIST may exhibit similar radiomics patterns irrespective of contrast agent; thus, radiomics models based on non-contrast-enhanced CT could be an alternative for risk stratification in GIST patients with contraindication to contrast agent.

KEY POINTS

• Performance of radiomics models in predicting Ki-67 proliferation based on different CT phases is evaluated. • Non-contrast-enhanced CT-based radiomics models performed similarly to contrast-enhanced CT in risk stratification in GIST patients. • NGTDM Busyness remains stable to contrast agents in GISTs in radiomics models.

Adjuvant therapy for rare rectal gastrointestinal stromal tumors: A case report

Key Clinical Message

Anorectal gastrointestinal stromal tumors are extremely rare, constituting less than 0.1% of rectal tumors. Surgical resection using a transanal wide excision followed by adjuvant therapy with tyrosine kinase inhibitors can be a successful treatment combination to remove the mass and prevent recurrence while preserving the integrity of the anal sphincter.

Abstract

Gastrointestinal stromal tumors (GISTs) are a rare subset of neoplasms, accounting for about 1%-2% of primary gastrointestinal malignancies. The stomach is the most common site for GISTs, with anorectal GISTs being exceptionally rare, representing only 0.1% of all rectal tumors. The standard approach for managing localized GIST involves complete surgical excision to achieve negative microscopic margins (R0) while preserving the tumor capsule and maintaining anal sphincter function. Surgical resection with transanal wide excision followed by adjuvant therapy using tyrosine kinase inhibitors can successfully remove the mass, prevent recurrence, and preserve the anal sphincter's integrity. Adjuvant therapy with imatinib is the recommended treatment for all localized GISTs assessed to have an intermediate or high risk of relapse. Here, we report a case of a 63-year-old male with a rectal GIST who underwent transanal wide excision followed by adjuvant therapy with tyrosine kinase inhibitors.

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.

I saw the Torricelli-Bernoulli sign: When physics provides imaging insights

The Torricelli-Bernoulli sign is a rare radiologic sign seen on computed tomography (CT) or magnetic resonance imaging (MRI), which helps direct the diagnosis of a gastrointestinal tumor. It indicates the presence of non-dependent air trapped within a necrotic ulcer located in a gastrointestinal tumor; sometimes, a vertical stream of bubbles emanating from the opening of the ulcer is present. The term Torricelli-Bernoulli sign first appeared in the literature in 1999, referring to the homonymous physical theorems.

Pimitespib for the treatment of advanced gastrointestinal stromal tumors and other tumors

Pimitespib (TAS-116) is the first heat shock protein 90 (HSP90) inhibitor approved in Japan, and it is indicated for the treatment of gastrointestinal stromal tumors (GIST) that have progressed after treatment with imatinib, sunitinib and regorafenib. This review describes the preclinical and clinical research with pimitespib, including its mechanism of action, pharmacokinetics, clinical antitumour activity and safety. In a phase III study, pimitespib significantly prolonged progression-free survival compared with placebo (median 2.8 vs 1.4 months; hazard ratio 0.51; 95% CI 0.30-0.87; p = 0.006). Common treatment-related adverse events were diarrhoea, decreased appetite, increase in serum creatinine, malaise, nausea and eye disorders. The efficacy and safety of pimitespib are being investigated in other tumour types and in combination with other anticancer therapies.

FBXW7 regulates the sensitivity of imatinib in gastrointestinal stromal tumors by targeting MCL1

BACKGROUND

Imatinib contributes to improving prognosis of high-risk or unresectable gastrointestinal stromal tumors (GISTs). As therapeutic efficacy is limited by imatinib resistance and toxicity, the exploration of predictive markers of imatinib therapeutic efficacy that enables patients to utilize more effective therapeutic strategies remains urgent.

METHODS

The correlation between FBXW7 and imatinib resistance via FBXW7-MCL1 axis was evaluated in vitro and in vivo experiments. The significance of FBXW7 as a predictor of imatinib treatment efficacy was examined in 140 high-risk patients with GISTs.

RESULTS

The ability of FBXW7 to predict therapeutic efficacy of adjuvant imatinib in high-risk GIST patients was determined through 5-year recurrence-free survival (RFS) rates analysis and multivariate analysis. FBXW7 affects imatinib sensitivity by regulating apoptosis in GIST-T1 cells. FBXW7 targets MCL1 to regulate apoptosis. MCL1 involves in the regulation of imatinib sensitivity through inhibiting apoptosis in GIST-T1 cells. FBXW7 regulates imatinib sensitivity by down-regulating MCL1 to enhance imatinib-induced apoptosis in vitro. FBXW7 regulates imatinib sensitivity of GIST cells by targeting MCL1 to predict efficacy of imatinib treatment in vivo.

CONCLUSIONS

FBXW7 regulates imatinib sensitivity by inhibiting MCL1 to enhance imatinib-induced apoptosis in GIST, and predicts efficacy of imatinib treatment in high-risk GIST patients treated with imatinib.

A Successful Central Gastrectomy and Gastro-Gastric Anastomosis for a Large Gastric GIST

PURPOSE

Partial gastrectomy is always the preferred technique for GIST resection. Central gastrectomy is a practical technique that can be employed in many situations during the resection of both subepithelial stromal tumors and gastric tumors.

CASE PRESENTATION

A 53-year-old Egyptian female patient with a 15 × 19 cm large fungating gastric GIST managed by central gastrectomy. Central gastrectomy and gastro-gastric anastomosis were performed with negative resection margins, and the patient received post-operative imatinib, achieving disease control throughout an 8-month post-operative follow-up.

CONCLUSION

Central gastrectomy is an effective method of partial gastrectomy that can be considered in GIST resection; however, more studies are needed to evaluate the efficiency of central gastrectomy in terms of long-term follow-up and terms of R0 respectability in gastric cancer.

Characteristics of gastrointestinal stromal tumors associated to other tumors: Características de los tumores del estroma gastrointestinal asociados a otras neoplasias

INTRODUCTION

Our aim is to analyze the differences between sporadic gastrointestinal stromal tumors and those associated with other tumors.

METHODS

Retrospective cohort study including patients with diagnosis of gastrointestinal stromal tumors operated at our center. Patients were divided into two groups, according to whether or not they had associated other tumors, both synchronously and metachronously. Disease free survival and overall survival were calculated for both groups.

RESULTS

96 patients were included, 60 (62.5%) were male, with a median age of 66.8 (35-84). An association with other tumors was found in 33 cases (34.3%); 12 were synchronous (36.3%) and 21 metachronous (63.7%). The presence of mutations in associated tumors was 70% and in non-associated tumors 75%. Associated tumors were classified as low risk tumors based on Fletcher's stratification scale (p = 0.001) as they usually were smaller in size and had less than ≤5 mitosis per 50 HPF compared to non-associated tumors. When analyzing overall survival, there were statistically significant differences (p = 0,035) between both groups.

CONCLUSION

The relatively high proportion of gastrointestinal stromal tumors cases with associated tumors suggests the need to carry out a study to rule out presence of a second neoplasm and a long-term follow-up should be carried out in order to diagnose a possible second neoplasm. Gastrointestinal stromal tumors associated with other tumors have usually low risk of recurrence with a good long-term prognosis.

Endoscopic resection for the treatment of gastric gastrointestinal stromal tumors: a retrospective study from a large tertiary hospital in China

BACKGROUND AND AIMS

With the continuous development of endoscopic technology, endoscopic resection (ER) has gradually become an optional method for the treatment of gastric gastrointestinal stromal tumors (GISTs). However, studies with a large sample or a long follow-up are lacking. Therefore, this research aims to evaluate the efficacy and safety of ER for gastric GISTs in the real-world setting with more than 300 enrolled patients and a follow-up period longer than 45 months.

METHODS

From January 2013 to February 2023, 409 patients with a pathological diagnosis of GISTs after ER were retrospectively enrolled in this study. After excluding 86 patients with non-gastric GISTs, we assessed 323 patients with gastric GISTs. The main outcome measures were en bloc resection, complete resection, residual disease, recurrence, and complications.

RESULTS

There were 194 (60.06%) females and 129 (39.94%) males, and the median age of the included patients was 58 years (51, 63). The median tumor size was 15.0 (10.0, 20.0) mm. According to the modified NIH criteria, 246 (75.85%) patients were classified as very low risk, 62 (19.20%) were classified as low risk, 12 (3.72%) were classified as moderate risk, and 3 (0.93%) were classified as high risk. A total of 287 (88.85%) patients achieved en bloc resection, and 287 (88.85%) also achieved complete resection. Only one patient showed residual and no recurrent lesions were noted during the follow-up. Regarding complications, three patients had complications, with a complication rate of 0.93%, and no severe complications requiring surgical intervention occurred.

CONCLUSION

ER is an appropriate alternative method for the treatment of gastric GISTs, with an en bloc resection rate of 88.85% and a complication rate of 0.93%. No recurrence was noted during follow-up, even for GISTs with piecemeal resection.

Referral patterns of GIST patients: data from a nationwide study

BACKGROUND

This study compares the characteristics, referral and treatment patterns and overall survival (OS) of gastrointestinal stromal tumor (GIST) patients treated in reference and non-reference centers in the Netherlands.

PATIENTS AND METHODS

This retrospective cohort study on patients diagnosed between 2016 and 2019, utilises data from the Netherlands Cancer Registry and the Dutch Nationwide Pathology Database. Patients were categorized into two groups: patients diagnosed in or referred to reference centers and patients diagnosed in non-reference centers without referral.

RESULTS

This study included 1,550 GIST patients with a median age of 67.0 in reference and 68.0 years in non-reference centers. Eighty-seven per cent of patients were diagnosed in non-reference centers, of which 36.5% (493/1,352) were referred to a reference center. Referral rates were higher for high-risk (62.2% [74/119]) and metastatic patients (67.2% [90/134]). Mutation analysis was performed in 96.9% and 87.6% of these cases in reference and in non-reference centers (p < 0.01), respectively. Systemic therapy was given in reference centers versus non-reference in 89.5% versus 82.0% (p < 0.01) of high-risk and in 94.1% versus 65.9% (p < 0.01) of metastatic patients, respectively. The proportion of positive resection margins and tumor rupture did not differ between reference and non-reference centers. Median OS was not reached.

CONCLUSION

A substantial amount of metastatic GIST patients in non-reference centers did not receive systemic treatment. This might be due to valid reasons. However, optimisation of the referral strategy of GIST patients in the Netherlands could benefit patients. Further research is needed to explore reasons for not starting systemic treatment in metastatic GIST patients.

Recurrent Gastrointestinal Stromal Tumor With Chondroid Differentiation After Imatinib Therapy: An Unusual Case and Literature Review

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor in the gastrointestinal tract and is most commonly seen in the stomach. The standard treatment for patients with advanced GISTs include both surgical resection and imatinib therapy. There have been cases that document the alterations of patients' GIST histomorphology both with primary GIST prior to imatinib therapy and with recurrent GIST after imatinib therapy. However, there has been no documented case of a patient who has recurrent GIST with chondroid differentiation at the primary site after imatinib therapy. In this article, we report an incidental finding of a 58-year-old patient who had two treatments of imatinib therapy prior to surgical resection of her recurrent GIST in her stomach. We also explore through a mini-literature review the various cases of GIST with chondroid differentiation that have been reported to compare the histomorphology, immunophenotype, and patient demographic of these cases. This article is significant for reporting a rare finding of GIST after imatinib therapy and highlights the various presentations that GIST could acquire after imatinib therapy that exclude another malignant process, such as chondrosarcoma.

Leiomyosarcoma of the rectum: A systematic review of recent literature

Leiomyosarcomas (LMSs) are rare tumors originating from the muscular layer. We performed a literature review of cases of confirmed rectal leiomyosarcomas (rLMSs) to clarify the history of such an infrequent tumor arising at such an uncommon location. In this research local recurrence was related to poorly differentiated rLMS and no other association between recurrence and any criteria was found. Concerning overall survival (OS), rLMS patients developing recurrence presented shorter longevity compared with the group without.

Advanced and Metastatic Gastrointestinal Stromal Tumors Presenting With Surgical Emergencies Managed With Surgical Resection: A Case Series

Advanced and metastatic gastrointestinal stromal tumors (GISTs) presenting with surgical emergencies are rare. Neoadjuvant imatinib being the treatment of choice for non-metastatic advanced disease with a proven role in downstaging the disease may not be feasible in patients presenting with bleeding and obstruction. We present a case series with retrospective analysis of a prospectively maintained database of patients with advanced and metastatic GISTs presenting with surgical emergencies. Clinical characteristics, imaging and endoscopic findings, surgical procedures, histological findings, and outcomes in these patients were studied. Four patients were included in this case series, with three males and one female (age range: 24-60 years). Two patients presented with melena; one with hemodynamic instability despite multiple blood transfusions underwent urgent exploratory laparotomy for bleeding gastric GIST, while the other underwent surgical exploration after careful evaluation given the recurrent, metastatic disease with a stable metabolic response on six months of imatinib. One patient with metastatic jejunal GIST who presented with an umbilical nodule and intestinal obstruction was given a trial of non-operative management for 72 hours, but due to non-resolution of obstruction, segmental jejunal en bloc resection with the dome of the urinary bladder with reconstruction and metastasectomy was needed. The patient with advanced gastric GIST who presented with gastric outlet obstruction was resuscitated, and an attempt of endoscopic naso-jejunal tube placement was tried, which failed, and exploration was needed. The mean length of hospital stay was 7.5 days. Histopathological examination confirmed GIST in all four patients with microscopic negative resection margins. All patients were started on imatinib with dose escalation to 800 mg in the patient with recurrent and metastatic disease; however, the patient with bleeding gastric GIST experienced severe adverse effects of imatinib and discontinued the drug shortly. All four patients are disease-free on follow-ups of 15 months, 48 months for the patient with advanced non-metastatic disease, and six and 24 months for the patients with metastatic disease. In the era of tyrosine kinase inhibitor (TKI) therapy for advanced and metastatic disease, upfront surgery is usually reserved for surgical emergencies only. Surgical resection, the cornerstone for the treatment of resectable GIST, may also be clinically relevant in metastatic settings, although it requires a careful and individualized approach.

Adaptation of endoscopic submucosal dissection techniques for endoscopic full-thickness resection: a review of key steps and technical aspects

BACKGROUND AND AIMS

GI stromal tumors (GISTs) represent the most common mesenchymal tumors of the GI tract. Guidelines recommend the removal of histologically proven gastric GISTs >2 cm. While the conventional treatment of a gastric GIST involves surgical excision, endoscopic full-thickness resection (EFTR) has been described as an acceptable alternative. We aim to outline how the key steps used in endoscopic submucosal dissection (ESD) can be adapted to the performance of exposed EFTR and discuss the variations in technical aspects between the 2 procedures.

METHODS

We use a video case illustration with a comprehensive narrative to highlight the similarities and differences in equipment used and techniques in EFTR and ESD. Images and graphical illustrations are also used to describe these techniques.

RESULTS

ESD techniques and equipment can be adapted for use in EFTR of gastric GISTs. Principles such as deep mucosal incision, the appropriate use of traction, and identification of vessels for prophylactic coagulation help to ensure a safe and efficient procedure. The main difference in EFTR is the need for general anesthesia, starting the mucosal incision as close to the tumor margin as possible, submucosal dissection around the surface of the tumor capsule, and a strong closure method for the muscle defect.

CONCLUSIONS

The equipment and techniques in ESD can be adapted to EFTR for gastric GISTs by endoscopists who are familiar with ESD techniques.

Successful excision of a giant stomach gastrointestinal stromal tumour-A case report

INTRODUCTION

Gastrointestinal stromal tumours are rare, but most common mesenchymal tumours originate from the gastrointestinal tract. Though surgery is the primary treatment, advanced tumours require targeted therapy in combination with surgery.

CASE PRESENTATION

A 62-year-old lady who presented with abdominal distention and pain was found to have a large abdominal mass. A contrast-enhanced computed tomography revealed a large abdominal mass extending from the epigastrium to the pelvis, with a solitary omental deposit. Despite receiving Imatinib for six months, the disease progressed, and she underwent open En block tumour excision with distal gastrectomy and distal pancreatectomy with Roux-en-Y gastrojejunostomy and part of omental resection after multi-disciplinary team discussions. Histological examination confirmed a spindle-type gastrointestinal stromal tumour, which arrived from the stomach's submucosa; immunohistochemistry showed strong cytoplasmic and membranous positivity for CD117.

CLINICAL DISCUSSION

While rare (0.1-3 % of GI malignancies), GISTs are most common in the stomach (56 %) and small bowel (32 %). Even large tumours can present with vague symptoms without obstructive features. Advanced tumours can be treated with targeted tumour therapy like Imatinib in combination with surgery. Surgical resection, usually laparoscopic, is the gold standard, but open surgery may be needed for large laparoscopically unresectable tumours.

CONCLUSION

Though large tumours may present with vague symptoms without obstructive features, they tend to be more aggressive and can progress despite imatinib therapy. While laparoscopic surgery is the gold standard, open surgery is preferable for large, laparoscopically unresectable tumours.

Unexpected reaction of "wild-type" gastrointestinal stromal tumor to imatinib: case report and literature review

Background

Most of gastrointestinal stromal tumors (GISTs) are driven by mutations in the KIT/PDGFRA genes and can benefit from TKIs treatment. However, a small subset of GIST (10%-15%) are called "wild-type" GISTs due to the lack of these mutations. Theoretically, they would not benefit from TKIs treatment and may even develop resistance. Therefore, this unexpected response may challenge inherent perceptions. Herein, we present a case of giant wild-type GIST exhibiting an unexpected response to imatinib(IM), followed by laparoscopic surgical resection. Subsequently, potential underlying mechanisms are discussed.

Case description

This case describes a 57-year-old man who presented with abdominal pain for two weeks. CT revealed a massive lesion near the splenic hilum along the greater curvature of the stomach, concurrently involving the splenic hilar vessels and surrounding lymph nodes. Ultrasound-guided fine needle aspiration biopsy confirmed it is a mesenchymal spindle cell tumor,GIST. Due to the enormous volume and local invasion, neoadjuvant chemotherapy was initially considered. After 6 months of IM 400 mg/d, CT imaging revealed marked changes in tumor heterogeneity and a significant reduction in volume. Subsequently, laparoscopic surgical resection was performed. Postoperative pathological examination, immunohistochemistry, and genetic testing collectively confirmed it is a wild-type GIST.The patient recovered well and was discharged on the 6th day after surgery, with continued oral IM(400 mg/d) after discharge. No recurrence was observed during follow-up until the publication of this report.

Conclusion

This unexpected response suggests that wild-type GISTs may benefit from TKIs treatment, and the potential mechanisms warrant further investigation. Additionally, true wild-type GIST may not be discerned due to current limitations of Next-Generation Sequencing(NGS). Therefore, for advanced/high-risk GIST, additional genetic analysis can be performed after negative NGS results.