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.

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.

Deep learning model combined with computed tomography features to preoperatively predicting the risk stratification of gastrointestinal stromal tumors

BACKGROUND Gastrointestinal stromal tumors(GIST)are prevalent neoplasm originating from the gastrointestinal mesenchyme.Approximately 50%of GIST patients experience tumor recurrence within 5 years.Thus,there is a pressing need to accurately evaluate risk stratification preoperatively.AIM To assess the application of a deep learning model(DLM)combined with computed tomography features for predicting risk stratification of GISTs.METHODS Preoperative contrast-enhanced computed tomography(CECT)images of 551 GIST patients were retrospectively analyzed.All image features were independently analyzed by two radiologists.Quantitative parameters were statistically analyzed to identify significant predictors of high-risk malignancy.Patients were randomly assigned to the training(n=386)and validation cohorts(n=165).A DLM and a combined DLM were established for predicting the GIST risk stratification using convolutional neural network and subsequently evaluated in the validation cohort.RESULTS Among the analyzed CECT image features,tumor size,ulceration,and enlarged feeding vessels were identified as significant risk predictors(P<0.05).In DLM,the overall area under the receiver operating characteristic curve(AUROC)was 0.88,with the accuracy(ACC)and AUROCs for each stratification being 87%and 0.96 for low-risk,79%and 0.74 for intermediate-risk,and 84%and 0.90 for high-risk,respectively.The overall ACC and AUROC were 84%and 0.94 in the combined model.The ACC and AUROCs for each risk stratification were 92%and 0.97 for low-risk,87%and 0.83 for intermediate-risk,and 90%and 0.96 for high-risk,respectively.Differences in AUROCs for each risk stratification between the two models were significant(P<0.05).CONCLUSION A combined DLM with satisfactory performance for preoperatively predicting GIST stratifications was developed using routine computed tomography data,demonstrating superiority compared to DLM.

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.

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.

Optical second-harmonic generation imaging for identifying gastrointestinal stromal tumors

Gastrointestinal stromal tumors(GISTs)are the most common mesenchymal tumors arising in the digest tract.It brings a challenge to diagnosis because it is asymptomatic clinically.It is well known that tumor development is often accompanied by the changes in the morphology of collagen fibers.Nowadays,an emerging optical imaging technique,second-harmonic generation(SHG),can directly identify collagen fibers without staining due to its noncentrosymmetric properties.Therefore,in this study,we attempt to assess the feasibility of SHG imaging for detecting GISTs by monitoring the morphological changes of collagen fibers in tumor microenvironment.We found that collagen alterations occurred obviously in the GISTs by comparing with normal tissues,and furthermore,two morphological features from SHG images were extracted to quantitatively assess the morphological difference of collagen fibers between normal muscular layer and GISTs by means of automated image analysis.Quantitative analyses show a significant difference in the two collagen features.This study demonstrates the potential of SHG imaging as an adjunctive diagnostic tool for label-free identification of GISTs.

Neurofibromatosis type 1 with multiple gastrointestinal stromal tumors:A case report

BACKGROUND Neurofibromatosis type 1(NF1)is characterized by café-au-lait patches on the skin and the presence of neurofibromas.Gastrointestinal stromal tumor(GIST)is the most common non-neurological tumor in NF1 patients.In NF1-associated GIST,KIT and PDGFRA mutations are frequently absent and imatinib is ineffective.Surgical resection is first-line treatment.CASE SUMMARY A 56-year-old woman with NF1 was hospitalized because of an incidental pelvic mass.Physical examination was notable for multiple café-au-lait patches and numerous subcutaneous soft nodular masses of the skin of the head,face,trunk,and limbs.Her abdomen was soft and nontender.No masses were palpated.Digital rectal examination was unremarkable.Abdominal computed tomography was suspicious for GIST or solitary fibrous tumor.Laparoscopy was performed,which identified eight well-demarcated masses in the jejunum.All were resected and pathologically diagnosed as GISTs.The patient was discharged on day 7 after surgery without complications.No tumor recurrence was evident at the 6-mo follow-up.CONCLUSION Laparoscopy is effective for both diagnosis and treatment of NF1-associated GIST.

Sunitinib-induced hyperammonemic encephalopathy in metastatic gastrointestinal stromal tumors:A case report

BACKGROUND Sunitinib,a multi-targeted tyrosine kinase inhibitor(TKI),has been approved for the salvage treatment of gastrointestinal stromal tumors(GIST).Hyperammonemic encephalopathy is a rare but severe complication of sunitinib use.Here,we present the case of a 66-year-old male with metastatic GIST without underlying liver cirrhosis who developed sunitinib-induced hyperammonemic encephalopathy.CASE SUMMARY A 66-year-old male with metastatic GIST was admitted because of reduced consciousness.Imatinib was administered as the first-line systemic therapy.He experienced repeated episodes of peritonitis due to tumor perforation,and surgery was performed.Progressive disease was confirmed based on increased liver metastasis,and sunitinib was initiated as a salvage treatment.However,23 d after the third course of sunitinib,he presented to the emergency room with an episode of altered consciousness and behavioral changes.Based on the patient clinical history and examination findings,sunitinib-induced encephalopathy was suspected.Sunitinib was discontinued,and the patient was treated for hyperammonemia.The patient had a normal level of consciousness four days later,and the serum ammonia level gradually decreased.No further neurological symptoms were reported in subsequent follow-ups.CONCLUSION TKI-induced hyperammonemic encephalopathy is potentially life-threatening.Patients receiving TKIs experiencing adverse reactions should undergo systemic evaluation and prompt treatment.

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

BACKGROUND Computed tomography(CT)imaging features are associated with risk stratification of gastric gastrointestinal stromal tumors(GISTs).AIM To determine the multi-slice CT imaging features for predicting risk stratification in patients with primary gastric GISTs.METHODS The clinicopathological and CT imaging data for 147 patients with histologically confirmed primary gastric GISTs were retrospectively analyzed.All patients had received dynamic contrast-enhanced CT(CECT)followed by surgical resection.According to the modified National Institutes of Health criteria,147 lesions were classified into the low malignant potential group(very low and low risk;101 lesions)and high malignant potential group(medium and high-risk;46 lesions).The association between malignant potential and CT characteristic features(including tumor location,size,growth pattern,contour,ulceration,cystic degeneration or necrosis,calcification within the tumor,lymphadenopathy,enhancement patterns,unenhanced CT and CECT attenuation value,and enhancement degree)was analyzed using univariate analysis.Multivariate logistic regression analysis was performed to identify significant predictors of high malignant potential.The receiver operating curve(ROC)was used to evaluate the predictive value of tumor size and the multinomial logistic regression model for risk classification.RESULTS There were 46 patients with high malignant potential and 101 with low-malignant potential gastric GISTs.Univariate analysis showed no significant differences in age,gender,tumor location,calcification,unenhanced CT and CECT attenuation values,and enhancement degree between the two groups(P>0.05).However,a significant difference was observed in tumor size(3.14±0.94 vs 6.63±3.26 cm,P<0.001)between the low-grade and high-grade groups.The univariate analysis further revealed that CT imaging features,including tumor contours,lesion growth patterns,ulceration,cystic degeneration or necrosis,lymphadenopathy,and contrast enhancement patterns,were associated with risk stratification(P<0.05).According to binary logistic regression analysis,tumor size[P<0.001;odds ratio(OR)=26.448;95%confidence interval(CI):4.854-144.099)],contours(P=0.028;OR=7.750;95%CI:1.253-47.955),and mixed growth pattern(P=0.046;OR=4.740;95%CI:1.029-21.828)were independent predictors for risk stratification of gastric GISTs.ROC curve analysis for the multinomial logistic regression model and tumor size to differentiate high-malignant potential from low-malignant potential GISTs achieved a maximum area under the curve of 0.919(95%CI:0.863-0.975)and 0.940(95%CI:0.893-0.986),respectively.The tumor size cutoff value between the low and high malignant potential groups was 4.05 cm,and the sensitivity and specificity were 93.5%and 84.2%,respectively.CONCLUSION CT features,including tumor size,growth patterns,and lesion contours,were predictors of malignant potential for primary gastric GISTs.

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

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

Preoperative prediction of malignant potential of 2-5 cm gastric gastrointestinal stromal tumors by computerized tomography-based radiomics

BACKGROUND The use of endoscopic surgery for treating gastrointestinal stromal tumors(GISTs)between 2 and 5 cm remains controversial considering the potential risk of metastasis and recurrence.Also,surgeons are facing great difficulties and challenges in assessing the malignant potential of 2-5 cm gastric GISTs.AIM To develop and evaluate computerized tomography(CT)-based radiomics for predicting the malignant potential of primary 2-5 cm gastric GISTs.METHODS A total of 103 patients with pathologically confirmed gastric GISTs between 2 and 5 cm were enrolled.The malignant potential was categorized into low grade and high grade according to postoperative pathology results.Preoperative CT images were reviewed by two radiologists.A radiological model was constructed by CT findings and clinical characteristics using logistic regression.Radiomic features were extracted from preoperative contrast-enhanced CT images in the arterial phase.The XGboost method was used to construct a radiomics model for the prediction of malignant potential.Nomogram was established by combing the radiomics score with CT findings.All of the models were developed in a training group(n=69)and evaluated in a test group(n=34).RESULTS The area under the curve(AUC)value of the radiological,radiomics,and nomogram models was 0.753(95%confidence interval[CI]:0.597-0.909),0.919(95%CI:0.828-1.000),and 0.916(95%CI:0.801-1.000)in the training group vs 0.642(95%CI:0.379-0.870),0.881(95%CI:0.772-0.990),and 0.894(95%CI:0.773-1.000)in the test group,respectively.The AUC of the nomogram model was significantly larger than that of the radiological model in both the training group(Z=2.795,P=0.0052)and test group(Z=2.785,P=0.0054).The decision curve of analysis showed that the nomogram model produced increased benefit across the entire risk threshold range.CONCLUSION Radiomics may be an effective tool to predict the malignant potential of 2-5 cm gastric GISTs and assist preoperative clinical decision making.

Study on vasculogenic mimicry in malignant esophageal stromal tumors

AIM: To investigate whether malignant esophageal stromal tumors contain PAS-positive patterned matrix-associated vascular channels, which are lined by tumor cells, but not vascular endothelial cells. That is vasculogenic mimicry (VM) independent of tumor angiogenesis. METHODS: Thirty-six tissue samples of malignant esophageal stromal tumors were analyzed. Tissue sections were stained for Vascular endothelial growth factor (VEGF), CD31 and periodic acid Schiff (PAS). The level of VEGF, the microvascular density (MVD) and the vasculogenic mimicry density (VMD) were determined. RESULTS: PAS-positive patterned matrix-associated vascular channels were detected in 33.3% (12/36) of tumor samples. Within these patterned channels, red blood cells were found. The level of VEGF and the MVD in tumors containing patterned channels were significantly higher than those in tumors not containing patterned channels (P < 0.05). At the same time, the malignant degree of tumors was higher, the proportions of tumors containing patterned channels were not only more, but also in the each kind of tumors containing patterned channels. CONCLUSION: In malignant esophageal stromal tumors, a VM mechanism causes some tumor cells to deform themselves and secrete extracellular matrix; thus, PAS-positive patterned matrix-associated vascular channels appear and supplying blood to the tumors to sustain their growth and metastasis.

Current research and treatment for gastrointestinal stromal tumors

Gastrointestinal stromal tumors(GISTs) are the most common mesenchymal tumors of the gastrointestinal tract and have gained considerable research and treatment interest,especially in the last two decades. GISTs are driven by mutations commonly found in the KIT gene and less commonly in the platelet-derived growth factor receptor alpha gene,BRAF gene and succinate dehydrogenase gene. GISTs behave in a spectrum of malignant potential,and both the tumor size and mitotic index are the most commonly used prognostic criteria. Whilst surgical resection can offer the best cure,targeted therapy in the form of tyrosine kinase inhibitors(TKIs) has revolutionized the management options. As the first-line TKI,imatinib offers treatment for advanced and metastatic GISTs,adjuvant therapy in high-risk GISTs and as a neoadjuvant agent to downsize large tumors prior to resection. The emergence of drug resistance has altered some treatment options,including prolonging the first-line TKI from 1 to 3 years,increasing the dose of TKI or switching to second-line TKI. Other newer TKIs,such as sunitinib and regorafenib,may offer some treatment options for imatinib-resistant GISTs. New molecular targeted therapies are being evaluated,such as inhibitors of BRAF,heat shock protein 90,glutamine and mitogenactivated protein kinase signaling,as well as inhibitors of apoptosis proteins antagonist and even immunotherapy. This editorial review summarizes the recent research trials and potential treatment targets that may influence our future patient-specific management of GISTs. The current guidelines in GIST management from Europe,North America and Asia are highlighted.

Endoscopic therapy for gastric stromal tumors originating from the muscularis propria

AIM:To explore endoscopic therapy methods for gastric stromal tumors originating from the muscularis propria.METHODS:For 69 cases diagnosed as gastric stromal tumors originating from the muscularis propria,three types of endoscopic therapy were selected,based on the size of the tumor.These methods included endoscopic ligation and resection(ELR),endoscopic submucosal excavation(ESE) and endoscopic full-thickness resection(EFR).The wound surface and the perforation of the gastric wall were closed with metal clips.Immunohistostaining for CD34,CD117,Dog-1,S-100 and smooth muscle actin(SMA) was performed on the resected tumors.RESULTS:A total of 38 cases in which the tumor size was less than 1.2 cm were treated with ELR;three cases were complicated by perforation,and the perforations were closed with metal clips.Additionally,18 cases in which the tumor size was more than 1.5 cm were treated with ESE,and no perforation occurred.Finally,13 cases in which the tumor size was more than 2.0 cm were treated with EFR;all of the cases were complicated by artificial perforation,and all of the perforations were closed with metal clips.All of the 69 cases recovered with medical treatment,and none required surgical operation.Immunohistostaining demonstrated that among all of the 69 gastric stromal tumors diagnosed by gastroscopy,12 cases were gastric leiomyomas(SMA-positive),and the other 57 cases were gastric stromal tumors.CONCLUSION:Gastric stromal tumors originating from the muscularis propria can be treated successfully with endoscopic techniques,which could replace certain surgical operations and should be considered for further application.

Laparoscopic management of gastric gastrointestinal stromal tumors: A retrospective 10-year single-center experience

AIM To determine the feasibility,safety,and oncological outcome of laparoscopic resection of gastric gastrointestinal stromal tumors(GISTs)based on favorable or unfavorable location.METHODS Our hospital database included 207 patients who underwent laparoscopic removal of gastric GISTs from January 2004 to September 2015.Patient demographics,clinical presentation,surgery,histopathology,postoperative course,and oncological outcomes were reviewed and analyzed.RESULTS Gastric GIST in favorable locations was present in81/207(39.1%)cases,and in unfavorable locations in 126/207(60.9%)cases.Overall mean tumor size was 3.28±1.82 cm.No conversions occurred,and complete R0 resection was achieved in 207(100%)cases.There were three incidences of iatrogenic tumor rupture.The feasibility and safety of laparoscopic surgery were comparable in both groups with no statistical difference between unfavorable and favorable location groups,respectively:for operative time:83.86±44.41 vs 80.77±36.46 min,P=0.627;conversion rate:0%vs 0%;estimated blood loss:27.74±45.2vs 29.59±41.18 m L,P=0.780;tumor rupture during surgery:0.90%vs 2.82%,P=0.322;or postoperative complications:3.74%vs 7.04%,P=0.325.The follow-up period recurrence rate was 1.89%with no significant differences between the two groups(3.03%vs 0%,P=0.447).Overall 5-year survival rate was98.76%and survival rates were similar between the two groups:98.99%vs 98.39%,P=0.623(unfavorable vs favorable,respectively).CONCLUSION The laparoscopic approach for gastric GISTs is safe and feasible with well-accepted oncological surgical outcomes.Strategies for laparoscopic resection should be selected according to the location and size of the tumor.Laparoscopic treatment of gastric GISTs in unfavorable locations should not be restricted in gastrointestinal centers.

Gastrointestinal stromal tumors:Thirty years experience of an Institution

AIM:To report our experience of gastrointestinal stromal tumors (GISTs) during the last 29 years. METHODS:Thirty two cases of GIST referred to our Institution from the 1st January 1981 to the 10th June 2010 were reviewed. Metastases,recurrence and survival data were collected in relation to age,history,clinical presentation,location,size,resection margins and cellular features. RESULTS:Mean age was 63.7 years (range,40-90) and incidence was slightly higher in males (56%). R0 resection was performed in 90.7% of cases,R1 in 6.2% (2 cases) and R2 in 3.1% (one case). Using Fletcher's classification 8/32 (25%) had high risk,9/32 (28%) intermediate and 15/32 (47%) low risk tumors. Follow-up varied from 1 mo to 29 years,with a median of 8 years; overall survival was 75% (24/32),disease-free survival was 72% and tumor-related mortality was 9.3%. Three patients with high risk GIST were treated with imatinib mesylate:one developed a recurrence after 36 mo,and 2 are free from disease at 41 mo. CONCLUSION:Surgical treatment remains the gold standard therapy for resectable GISTs. Pathological and biological features of the neoplasm represent the most important factors predicting the prognosis.

Primary multiple extragastrointestinal stromal tumors of the omentum with different mutations of c-kit gene

The author reports a very rare case of sporadic primary multiple extragastrointestinal stromal tumors (EGISTs) of the omentum associated with different mutations of the exon 11 of the c-kit gene in a 75-year-old man with gastric cancer. During an operation for the cancer, two solid tumors (10 mm and 8 mm) were found in the omentum. Both tumors consisted of cellular spindle cells. Mitotic figures were two and three per 50 high power fields. The tumor cells were positive for KIT, CD34 and vimentin, but negative for desmin, S100 protein, α-smooth muscle actin and p53 protein. Ki67 labeling was 2% and 3%. The larger EGIST showed a deletion of codons 552-558 of exon 11 of the c-kit gene, while the smaller EGIST had a point mutation at codon 559 (GTT←GAT) in exon 11 of the c-kit gene. Exons 9, 13, and 17 of the c-kit gene, and exons 12 and 18 of the platelet derived growth factor receptor α genes showed no mutations. The case shows that sporadic multiple EGISTs can occur in the omentum.

DNA ploidy and c-Kitmutation in gastrointestinal stromal tumors

AIM: To investigate the prognostic significance of c-Kitgen emutation and DNA ploidy in gastointestinal stromal tumors (GISTs).METHODS: A total of 55 cases of GISTs were studied for the expression of c-Kit by immunohistochemistry, and the c-Kit gene mutations in exons 9, 11, 13, and 17 were detected by polymerase chain reaction-single strand confirmation polymarphism (PCR-SSCP) and denaturing high performance liquid chromatography (D-HPLC) techniques. DNA ploidy was determined by flow cytometry.RESULTS: Of the 55 cases of GISTs, 53 cases (96.4%) expressed c-Kit protein. The c-Kit gene mutations of exons 11 and 9 were found in 30 (54.5%) and 7 cases (12.7%),respectively. No mutations were found in exons 13 and 17.DNA aneuploidy was seen in 10 cases (18.2%). The c-Kit mutation positive GISTs were larger in size than the negative GISTs. The aneuploidy tumors were statistically associated with large size, high mitotic counts, high risk groups, high cellularity and severe nuclear atypia, and epithelioid type.There was a tendency that c-Kit mutations were more frequently found in aneuploidy GISTs.CONCLUSION: DNA aneuploidy and c-Kit mutations can be considered as prognostic factors in GISTs.

Endoscopic full-thickness resection and laparoscopic surgery for treatment of gastric stromal tumors

AIM: To assess the effectiveness of endoscopic full-thickness resection (EFR) and laparoscopic surgery in the treatment of gastric stromal tumors arising from the muscularis propria.

Interventional digital subtraction angiography for small bowel gastrointestinal stromal tumors with bleeding

AIM: To retrospectively evaluate the diagnostic efficacy of interventional digital subtraction angiography (DSA) for bleeding small bowel gastrointestinal stromal tumors (GISTs).