Two different mutational types of familial gastrointestinal stromal tumors:Two case reports

BACKGROUND Gastrointestinal stromal tumors(GISTs)are the most common mesenchymal tumors of the gastrointestinal(GI)tract,and cases of GISTs tend to be of the disseminated type,with a global incidence of 10 to 15 cases/million each year.The rarer familial GISTs,which often represent a population,differ in screening,diagnosis,and treatment.Familial GISTs include primary familial GISTs with predominantly KIT/PDGFRA mutations and wild-type GISTs.However,whether the same genetic family has different phenotypes has not been reported.CASE SUMMARY We report two cases of rare GISTs in the same family:A male patient with the V561D mutation in exon 12 of the PDGFRA gene,who has been taking the targeted drug imatinib since undergoing surgery,and a female patient diagnosed with wild-type GIST,who has been taking imatinib for 3 years since undergoing surgery.The favorable prognosis of these patients during the 7-year follow-up period validates the accuracy of our treatment strategy,and we have refined the entire process of diagnosis and treatment of familial GISTs in order to better manage this rare familial disease.CONCLUSION Different mutation types of familial GISTs in the same family are very rare,thus it is very important to make the correct diagnosis and treatment strategies according to the results of molecular detection for the management of familial GISTs.

Extragastrointestinal stromal tumors with diffuse membranous distribution with bleeding:A case report

BACKGROUND Extragastrointestinal stromal tumors(EGIST)and gastrointestinal stromal tumors are of similar pathological type and form.Here we report a rare case of EGIST diffusely distributed in membranous tissue in abdominal cavity,the feature of which included diffuse tumors at membranous tissue in entire abdominal cavity and spontaneous bleeding of the tumors.CASE SUMMARY The patient was a 71-year man and hospitalized due to continuous pain at lower abdomen for more than 10 days.Upon physical examination,the patient had flat and tough abdomen with mild pressing pain at lower abdomen,no obvious abdominal mass was touchable,and shifting dullness was positive.Positron emission tomography-computed tomography(CT)showed that in his peritoneal cavity,there were multiple nodules of various sizes,seroperitoneum,multiple enlarged lymph nodes in abdominal/pelvic cavity and right external ilium as well as pulmonary nodules.Plain CT scanning at epigastrium/hypogastrium/pelvic cavity+enhanced three-dimensional reconstruction revealed multiple soft tissue nodules in abdominal/pelvic cavity,peritoneum and right groin.Tumor marker of carbohydrate antigen 125 was 808 U/mL,diffuse tuberous tumor was seen in abdominal/pelvic cavity during operation with hematocelia,and postoperative pathological examination confirmed EGIST.Imatinib was administered with better therapeutic effect.CONCLUSION Gene testing showed breast cancer susceptibility gene 1 interacting protein C-terminal helicase 1 and KIT genovariation,and the patient was treated with imatinib follow-up visit found that his clinical symptoms disappeared and the tumor load alleviated obviously via imageological examination.

Gastric IgG4-related disease mimicking a gastrointestinal stromal tumor in a child: A case report

BACKGROUND Gastric IgG4-related disease(IgG4-RD)is rarely encountered in clinical practice,and especially more so among pediatric patients.To our knowledge,this is the first report of IgG4-RD presenting as a calcifying gastric mass in a child.We describe how this entity was difficult to differentiate from a gastrointestinal stromal tumor(GIST)imaging-based approaches.Therefore,this case highlights the importance of considering IgG4-RD in the differential diagnosis of gastric tumor before performing surgical resection,especially to distinguish it from malignancy to avoid unnecessary surgery.CASE SUMMARY The patient suffered from epigastric pain for several days.Panendoscopy and computed tomography scan revealed a submucosal tumor.Differential diagnoses included GIST,leiomyoma,teratoma,and mucinous adenocarcinoma.However,laparoscopic proximal gastrectomy allowed for the definitive diagnosis of IgG4-related stomach disease.CONCLUSION We emphasize the importance of considering IgG4-RD in the differential diagnosis of gastric submucosal tumors before performing surgical resection.

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,OEIGF2 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 overexpressionmediated imatinib resistance in GISTs.CONCLUSION IGF2 targeting of IGF1R signaling inhibited metastasis and decreased imatinib resistance by driving glycolysis in GISTs.

Effect and safety of ripretinib in the treatment of advanced gastrointestinal stromal tumor:A systematic review and metaanalysis

BACKGROUND Imatinib(IMA)has received approval as the primary treatment for gastrointestinal stromal tumors(GIST).Nonetheless,approximately half of the patients with advanced GIST show disease advancement following IMA treatment.Presently,the efficacy of secondary and tertiary medications in addressing various GIST secondary mutations is somewhat restricted.Consequently,there is a significant medical demand for the creation of kinase inhibitors that extensively block secondary drug-resistant mutations in advanced GIST.Ripretinib(RPT)is a new,switch-control tyrosine kinase inhibitors that can suppress different mutations of KIT and PDGFRA via a dual mechanism of action.AIM To investigate the literature on RPT to assess an effective,safe,and successful treatment strategy against advanced GIST.METHODS The present systematic review and meta-analysis was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.PubMed,Embase,Cochrane,Web of Science and ClinicalTrials.gov databases were screened from January 1,2003 to May 1,2024.RESULTS A total of 4 studies were included,with a total of 507 patients enrolled.The objective response rate(ORR)of the RPT-treated advanced GIST was 17%(95%CI:0.11-0.27),while the disease control rate(DCR)was 66%(95%CI:0.59-0.73).The overall occurrence of adverse events with varying degrees was 97%(95%CI:0.93-1),whereas that of grade≥3 adverse reactions was 42%(95%CI:0.28-0.63).The sensitivity analysis revealed that omitting some studies did not yield statistically notable variances in the aggregate data regarding the ORR,DCR,and the occurrence of adverse events of grade 3 or higher.The publication bias was absent because no significant asymmetry was observed in Begg’s funnel plot in all studies.CONCLUSION RPT has favorable efficacy profiles in GIST patients,but the adverse reactions are obvious,and patient management needs to be strengthened to achieve better safety and tolerability.

Systemic therapy in gastrointestinal stromal tumors

Gastrointestinal stromal tumors(GISTs)are the most common type of soft tissue sarcoma in the gastrointestinal tract.Most GISTs have been attributed to activated gain-of-function mutations in either KIT or platelet-derived growth factor receptorα,making these molecular features essential targets for therapeutic interventions.Although surgery is the standard treatment for localized GISTs,patients often experience relapse and disease progression even after surgery.In recent years,targeted therapy has significantly improved the prognosis of patients with advanced GISTs.Imatinib mesylate,a KIT inhibitor,is the first-line treatment for advanced GISTs and has revolutionized the treatment of this disease.However,drug resistance remains a major issue with imatinib treatment,as a significant majority of patients become resistant to imatinib either after initiation or after 2–3 years of treatment.Consequently,novel tyrosine kinase inhibitors such as sunitinib,regorafenib,ripretinib,and avapritinib have been introduced to address drug resistance.Immunotherapy has emerged as a potential approach for the treatment of advanced GISTs.This review comprehensively summarizes the pathogenesis of GISTs and the development of targeted therapies and immunotherapies,provides an overview of the emergence of drug resistance in advanced GISTs,and discusses the challenges and prospects associated with the treatment of GISTs.

Advancing gastrointestinal stromal tumor management: The role of imagomics features in precision risk assessment

BACKGROUND Gastrointestinal stromal tumors(GISTs)vary widely in prognosis,and traditional pathological assessments often lack precision in risk stratification.Advanced imaging techniques,especially magnetic resonance imaging(MRI),offer potential improvements.This study investigates how MRI imagomics can enhance risk assessment and support personalized treatment for GIST patients.AIM To assess the effectiveness of MRI imagomics in improving GIST risk stratification,addressing the limitations of traditional pathological assessments.METHODS Analyzed clinical and MRI data from 132 GIST patients,categorizing them by tumor specifics and dividing into risk groups.Employed dimension reduction for optimal imagomics feature selection from diffusion-weighted imaging(DWI),T1-weighted imaging(T1WI),and contrast enhanced T1WI with fat saturation(CET1WI)fat suppress(fs)sequences.RESULTS Age,lesion diameter,and mitotic figures significantly correlated with GIST risk,with DWI sequence features like sphericity and regional entropy showing high predictive accuracy.The combined T1WI and CE-T1WI fs model had the best predictive efficacy.In the test group,the DWI sequence model demonstrated an area under the curve(AUC)value of 0.960 with a sensitivity of 80.0%and a specificity of 100.0%.On the other hand,the combined performance of the T1WI and CE-T1WI fs models in the test group was the most robust,exhibiting an AUC value of 0.834,a sensitivity of 70.4%,and a specificity of 85.2%.CONCLUSION MRI imagomics,particularly DWI and combined T1WI/CE-T1WI fs models,significantly enhance GIST risk stratification,supporting precise preoperative patient assessment and personalized treatment plans.The clinical implications are profound,enabling more accurate surgical strategy formulation and optimized treatment selection,thereby improving patient outcomes.Future research should focus on multicenter studies to validate these findings,integrate advanced imaging technologies like PET/MRI,and incorporate genetic factors to achieve a more comprehensive risk assessment.

A gist of gastrointestinal stromal tumors: A review

Gastrointestinal stromal tumors (GISTs) have been recognized as a biologically distinctive tumor type, different from smooth muscle and neural tumors of the gastrointestinal tract (GIT). They constitute the majority of gastrointestinal mesenchymal tumors of the GIT and are known to be refractory to conventional chemotherapy or radiation. They are defined and diagnosed by the expression of a proto-oncogene protein detected by immunohistochemistry which serves as a crucial diagnostic and therapeutic target. The identification of these mutations has resulted in a better understanding of their oncogenic mechanisms. The remarkable antitumor effects of the molecular inhibitor imatinib have necessitated accurate diagnosis of GIST and their distinction from other gastrointestinal mes-enchymal tumors. Both traditional and minimally invasive surgery are used to remove these tumors with minimal morbidity and excellent perioperative outcomes. The revolutionary use of specific, molecularlytargeted therapies, such as imatinib mesylate, reduces the frequency of disease recurrence when used as an adjuvant following complete resection. Neoadjuvant treatment with these agents appears to stabilize disease in the majority of patients and may reduce the extent of surgical resection required for subsequent complete tumor removal. The important interplay between the molecular genetics of GIST and responses to targeted therapeutics serves as a model for the study of targeted therapies in other solid tumors. This review summarizes our current knowledge and recent advances regarding the histogenesis, pathology, molecular biology, the basis for the novel targeted cancer therapy and current evidence based management of these unique tumors.

STI571 (Glivec) suppresses the expression of vascular endothelial growth factor in the gastrointestinal stromal tumor cell line,GIST-T1

AIM： To estimate whether S-TI571 inhibits the expression of vascular endothelial growth factor （VEGF） in the gastrointestinal stromal tumor （GIST） cells. METHODS： We used GIST cell line, GIST-T1. It has a heterogenic 57-bp deletion in exon 11 to produce a mutated c-KIT, which results in constitutive activation of c-KIT. Cells were treated with/without STI571 or stem cell factor （SCF）. Transcription and expression of VEGF were determined by RT-PCR and flow cytometry or Western blotting, respectively. Activated c-KIT was estimated by immunoprecipitation analysis. Cell viability was determined by PITT assay. RESULTS： Activation of c-KIT was inhibited by STI571 treatment. VEGF was suppressed at both the transcriptional and translational levels in a temporal and dose-dependent manner by STI571. SCF upregulated the expression of VEGF and it was inhibited by S-13571. STI571 also reduced the cell viability of the GIST-T1 cells, as determined by PTT assay. CONCLUSION： Activation of c-KIT in the GIST-T1 regulated the expression of VEGF and it was inhibited by ST571. STI571 has antitumor effects on the GIST cells with respect to not only the inhibition of cell growth, but also the suppression of VEGF expression.

GASTROINTESTINAL STROMAL TUMORS OF THE ANORECTUM——A SPECIAL ENTITY: GISTs OF THE ANORECTUM

Objective： Until recently gastrointestinal stromal tumor （GIST） has been separated from other mesenchymal neoplasms and categorized as a special entity. Morphology of tumor cells and immunohistochemical findings with CD117 are crucial in the pathological diagnosis of GISTs. Newly developed drug imatinib mesylate （formerly called STI571） has been proved effective for GISTs. The distinction of GISTs and other mesenchymal tumors has great clinical significance, especially for lesions located in the anorectum. Methods： The authors searched the database of Peking University, School of Ontology for patients with anorectal neoplasms treated from January 1995 to June 2002. Information of 12 patients with anorectal mesenchymal tumors was collected. The patients were reevaluated and discussed according to current criteria of GISTs with clinical data and immunohistochemical findings. Results： Six patients （including 3 males） were finally diagnosed as anorectal GISTs. The median age of those patients was 59.5 years （27～69）. The symptoms were not specific. Three cases with original diagnosis of leiomyoma or leiomyosarcoma were actually GISTs. A total of six anorectal GISTs was found comprising about 1.06% of patients with anorectal neoplasmas in the same period. Besides CD117, CD34 and vimentin were also expressed in majority of these patients. Five of the six patients underwent surgical resection one of which received neoadjuvant chemotherapy before resection Conclusion： Anorectal GISTs should be considered as a special entity using current diagnostic criteria. Surgical resection remains the primary therapeutic strategy. Neoadjuvant imatinib mesylate may be helpful in sphincter-sparing operations and improvement of the quality of life for these patients.

Primary Extra-Gastrointestinal Stromal Tumor (GIST) arising from mesentery of small bowel and presenting as abdominal mass: A rare entity

Introduction: Majority of mesenchymal tumors of gastrointestinal tract are Gastrointestinal Stromal Tumor (GIST). It is, however, a rare tumor, accounting for less than 1% of primary gastrointestinal (GI) neoplasms. Though, these tumors are refractory to conventional chemotherapy or radiotherapy but show a good response to targeted adjuvant chemotherapy with tyrosine kinase inhibitors following surgical resection. Case Report: we report here a case of primary Extra-GIST tumor arising from mesentry of small bowel near duodeno-jejunal junction in a 69 years old male patient. The patient presented with a palpable mass in upper abdomen for past 15 days. On examination, a non-tender mobile lump of size around 17 × 10 cm, with bosselated surface and firm in consistency was palpable involving epigastric, left hypochondrium and umbilical region. Contrast enhanced computed tomography of abdomen revealed a heterogenous mesentric mass. On surgical intervention a mass was found involving mesentery near dudenojejunal junction without involvement of gastrointestinal tract. Complete surgical resection of the tumor was done and adjuvant chemotherapy with Imatinib mesylate was started as HPE revealing GIST with mitotic index of >10/50 HPF and 17 × 10 cm size placed the patient in high risk category. Patient was discharged on 12th of post-operative day with advice of regular follow-up. Conclusion: GIST occurrence is not restricted to bowel but can involve unusual sites also. The mainstay of treatment remains surgical resection with adequate margin. In cases where tumour has malignant potential (high mitotic figures on histopathology) adjuvent treatment with tyrosine kinase may prevent or delay relapse.

Gastrointestinal Stromal Tumor (GIST) with Chondroid-Myxoid-Chordoid Features Mimicking Extraskeletal Myxoid Chondrosarcoma

Epithelioid gastrointesinal tumors (GISTs) are less likely to have c-kit gene mutations (and express CD117) than spindle cell GISTs. CD117 negative/c-kit negative GISTs can have platelet-derived growth factor alpha (PDGFRα) gene mutations, overexpress PDGFRα protein and respond to imatinib mesylate. Many cases of CD117-negative/CD117-weakly positive, c-kit mutation negative and PDGFRα mutation positive myxoid epithelioid GISTs and one case of CD117-positive GIST with chondro-myxoid features mimicking chondrosarcoma have been reported. We report a case of myxoid epithelioid GIST with predominance of chondroid and chordoid areas resembling an extraskeletal myxoid chondrosarcoma that was strongly positive for CD117, PDGFRα and DOG1 (Discovered on GIST 1) by immunohistochemistry, but lacked c-kit and PDGFRα gene mutations. It is possible that CD117 is strongly positive if a myxoid epithelioid GIST has chondroid/chordoid appearance, but a larger study is needed to confirm this association. CD117 expression in GISTs is important, because GISTs showing CD117 positivity respond to imatinib. No comment can be made about the prognostic significance of chondroid/chordoid appearance in the GISTs.

A Rare Cause of Pneumoperitoneum: Perforated Gastrointestinal Stromal Tumor (GIST)

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor and has a malignant potential. The clinical presentation with pneumoperitoneum and peritonitis is extremely rare. We report a case of a 40-year-old male presented with symptoms of acute abdomen. Radiological work-up confirmed pneumoperitoneum. Emergency laparatomy and complete resection were performed. The final diagnosis revealed perforated GIST originating from the jejunum. If an abdominal mass presents with pneumoperitoneum and peritonitis, jejunal GIST should be considered in diagnosis. A complete radical resection followed by postoperative adjuvant chemotheraphy with Imatinib is recommended.

Giant 10 cm Diameter Esophageal Gastrointestinal Stromal Tumor (GIST)

Gastrointestinal stromal tumor (GIST) is a relatively rare type of cancer that affects an estimated 5000 to 10,000 new people each year in the US. Most GIST tumors develop in the stomach;but they can also arise in the small intestine, colon and rectum, esophagus or abdominal cavity. Gastrointestinal stromal tumors are the most common mesenchymal, nonepithelial tumors of the gastrointestinal tract in adults between 40 and 50 years of age. Esophageal GIST, in contrast, is rare, amounting to 12.7% - 28% of mesenchymal esophageal tumors or 2% of all GISTs and their diagnosis and management are still challenging, as illustrated in the following case. However here we report a rare case of a 43-year-old female patient who was referred to our department complaining with a 1-month history of atypical chest pain and productive cough. A chest computed tomographic scan and endoscopic ultrasound revealed a submucosal esophageal tumor measuring 100 × 80 × 40 mm in its largest diameter, we performed enucleation via left thoracotomy.

Results of the Management of Gastrointestinal Stromal Tumors (GIST): About 6 Cases at the Vichy Hospital Center (France)

The aim of our study was to analyze the results of surgical management of gastrointestinal stromal tumors (GIST) at the Vichy Hospital Center. Methodology: Between 2010 and 2020, the data of 6 patients operated at the Vichy Hospital Center for GIST were analyzed. The parameters studied were: age, sex, antecedents, discovery circumstances, imagery, surgical procedure, anatomopathological data, the follow-up and the morbidity-mortality. Results: There were 5 men and one woman with an average age of 72.16 years [58 - 80 years]. The average time of evolution was 8 months (0 - 14 months). The diagnosis was fortuitous in 2 cases. Atypical abdominal pain was the main symptom in 3 cases. One case was received in a clinical picture of peritoneal irritation syndrome. Echo-endoscopy with biopsy specimen histology made it possible to make the diagnosis in 5 cases and the surgical specimen in 1 case. The fusiform type was the predominant histological form. The stomach was the most common location. The average size of GISTs was 7.3 × 4 cm with a positive C Kit in all patients. Neoadjuvant chemotherapy was performed on one patient. Surgery was curative and was done laparoscopically on 4 patients. Adjuvant chemotherapy based on Imatinib at a rate of 400 mg/d in 3 patients was initiated. One patient presented a fistula of the esophagus-jejunal anastomosis on D6 post operation controlled by a drainage and an antibiotic therapy. Mortality was zero. During the surgery, all of the patients were followed up with surgeon, oncologist. Conclusion: GISTs are the most common mesenchymal tumors of the digestive tract with a preferential gastric location. Laparoscopic surgery, with advances in molecular biology and the introduction of targeted therapy has improved the management of these tumors in terms of morbidity and mortality.

Gastrointestinal Stromal Tumors (GISTs), Surgical Management and Clinical Outcome

Introduction: This study investigated the incidence, surgical management and outcome of Gastrointestinal Stromal Tumors (GIST) in Upper Egypt. Methods: A retrospective review of all GIST patients admitted a South Egypt Cancer Institute between Jan. 2010 and Dec. 2015 was conducted. Patients’ demographics, clinical presentation, tumor characteristics, radiological, pathological and immunohistochemical findings, surgical procedures, recurrence and mortality were recorded. Results: A total of 36 GIST patients were identified, stomach was the most common site (27.8%) followed by the small intestine (19.4%) and the large intestine (16.7%). The mean age at time of diagnosis as 52.8 ± 14.4 (ranged from 17 to 76 years). Of these 36 cases, 20 (55.6%) cases were males and 16 (44.4%) cases were females with a ratio of 1.2:1. About 22 cases (61.1%) presented with primary tumors, eight cases (22.2%) had primary tumors and metastases, three cases (8.35) presented with recurrent mass, whereas one case (2.2%) presented either with recurrent mass and metastases or metastases only. The majority of cases (22) had tumorsize >5 cm. Patients were stratified as high, intermediate, low and very low risk (50.6%, 30.6%, 11.1% and 2.8%, respectively). Almost all the cases were surgically managed and 75% were completely resectable. During follow up (average 26.5 months), 22 patients showed complete recovery, 7 had recurrent or metastatic disease and 2 died due to liver metastasis. Conclusion: The incidence of GIST in Upper Egypt is apparently low. Surgical resection is the preferred choice of treatment. The demographic data of GIST patients in South Egypt Cancer institute were similar to those published in the literature. Other prospective studies are required to assess the prognosis and the effect of treatment.

Management Colorectal Gastrointestinal Stromal Tumors (Gists) in Surabaya

Introduction: Colorectal gastrointestinal stromal tumors (GISTs) mesenchymal tumor is very uncommon. GISTs effect mostly on the stomach and small intestine and rarely occur in the colon, rectum and esophagus, that originating from precursors of the interstitial cells that originate of Cajal. The symptoms of gastrointestinal stromal tumor depend on the site and size of the tumor, and may include abdominal pain, gastrointestinal bleeding or signs of obstruction;small tumors may, however, be asymptomatic. Some of the patients with gastrointestinal stromal tumor have bloody stools, obstruction and abdominal pain as the commonest manifestation. Immunocytochemical staining for CD117 is helpful in confirming the diagnosis. Case presentation: We report 3 new cases of GISTs: two occurred at the rectal and the other at descending Colon. Two cases are over 50 years of age and, and all cases the chief complain of bowel obstruction, abdominal pain in two cases, and one case with anemia and urine retention. All the patients were operated and were permormed pathology examinatiom. All case ware positive result for immunocytochemical staining CD117. All cases we had presented had size more than 5 cm are considered as unfavorable prognostic factors to Fletcher criteria, all patients scheduled for chemotherapy with Glivec but just one patient continued to used Glivec. Post surgery follows up one patient post milles with urinary incontinence complaints found and that patients are trained to CIC (intermittent catheterization). Conclusion: Colorectal gastrointestinal stromal tumors are very rare and can present as mass abdomen. Resection and chemotherapy are the treatment of choice.

Current clinical management of gastrointestinal stromal tumor

Gastrointestinal stromal tumors(GISTs) are the most common malignant subepithelial lesions(SELs) of the gastrointestinal tract. They originate from the interstitial cells of Cajal located within the muscle layer and are characterized by over-expression of the tyrosine kinase receptor KIT. Pathologically, diagnosis of a GIST relies on morphology and immunohistochemistry [KIT and/or discovered on gastrointestinal stromal tumor 1(DOG1) is generally positive]. The prognosis of this disease is associated with the tumor size and mitotic index. The standard treatment of a GIST without metastasis is surgical resection. A GIST with metastasis is usually only treated by tyrosine kinase inhibitors without radical cure; thus, early diagnosis is the only way to improve its prognosis. However, a GIST is usually detected as a SEL during endoscopy, and many benign and malignant conditions may manifest as SELs. Conventional endoscopic biopsy is difficult for tumors without ulceration. Most SELs have therefore been managed without a histological diagnosis. However, a favorable prognosis of a GIST is associated with early histological diagnosis and R0 resection. Endoscopic ultrasonography(EUS) and EUS-guided fine needle aspiration(EUSFNA) are critical for an accurate diagnosis of SELs. EUSFNA is safe and effective in enabling an early histological diagnosis and adequate treatment. This review outlines the current evidence for the diagnosis and management of GISTs, with an emphasis on early management of small SELs.

Chinese consensus guidelines for diagnosis and management of gastrointestinal stromal tumor

In order to further promote the standardization of diagnosis and treatment of gastrointestinal stromal tumor （GIST） in China, the members of Chinese Society of Clinical Oncology （CSCO） Expert Committee on GIST thoroughly discussed the key contents of the consensus guidelines, and voted on the controversial issue. In final, the Chinese consensus guidelines for the diagnosis and management of GIST （2017 edition） was formed on the basis of 2013 edition consensus guidelines, which is hereby announced. The consensus included the pathological diagnosis, recurrence risk classification evaluation, targeted agent therapy, surgery and principles of surveillance of GIST.

Rectal gastrointestinal stromal tumors:Imaging features with clinical and pathological correlation

AIM:To investigate computed tomography(CT) and magnetic resonance imaging(MRI) manifestations of rectal gastrointestinal stromal tumors(GISTs) in order to enhance the recognition of these rare tumors.METHODS:Fourteen patients with pathologically proven rectal GISTs were retrospectively reviewed.Patient histories were retrospectively reviewed for patient age,gender,presenting symptoms,endoscopic investigations,operation notes and pathologic slides.All tumors were evaluated for CD117,CD34 expression,and the tumors were stratified according to current criteria of the National Institutes of Health(NIH).In all cases the first pre-operation imaging findings(CT and MRI,n = 3;MRI only,n = 8;CT only,n = 3) were analyzed by two experienced radiologists by consensus,which include:tumor size,shape,CT density(hypodense,isodense and hyperdense),MRI signal intensity(hypointense,isointense and hyperintense),epicenter(intraluminal or extraluminal),margin(well-defined or ill-defined),internal component(presence of calcifications,necrosis,hemorrhage or ulceration),pattern and degree of enhancement,invasion into adjacent structures.After review of the radiologic studies,clinical and pathological findings were correlated with radiological findings.RESULTS:The patients,13 men and 1 woman,were aged 31-62 years(mean = 51.5 ± 10.7 years).The most common initial presentation was hematochezia(n = 6).The mean tumor diameter was 5.68 ± 2.64 cm(range 1.5-11.2 cm).Eight lesions were round or oval,and 6 lesions were irregular.Eleven lesions were welldefined and 3 had ill-defined margins.Ten tumors were extraluminal and 4 were intraluminal.The density and MR signal intensity of the solid component of the lesions were similar to that of muscle on unenhanced CT(n = 6) and T1-weighted images(n = 11),and hyperintense on T2-weighted MR images.Calcification was detected in 2 tumors.Following intravenous injection of contrast media,3 lesions had mild enhancement and 11 lesions had moderate enhancement.Enhancement was homogenous in 3 lesions and heterogeneous in 11.In 1 of 11 patients who underwent both CT and MRI,the tumor was homogenous on CT scan and heterogeneous on MRI.Eight patients were classified as high risk according to the modified recurrent risk classification system of NIH.CONCLUSION:Rectal GISTs usually manifest as large,well-circumscribed,exophytic masses with moderate and heterogeneous enhancement on CT and MRI.The invasion of adjacent organs,bowel obstruction and local adenopathy are uncommon.