Purpose To characterize the clinicopathological features of gastrointestinal mesenchymal tumors(GMTs)resected via endoscopic techniques.Methods A retrospective analysis was conducted on 495 cases of endo-scopically resected GMTs.Clinical information,histomorphological findings,immunohistochemical profiles,and mo-lecular characteristics were reviewed.Results The cohort included 495 patients aged 20-78 years(median:53 years).The majority of tumors were located in the stomach(58.8％)and esophagus(36.8％).Histologically,most tumors consisted of spindle cells,with a minority composed of epithelioid cells;fibrocollagenous or myxoid stroma was occasionally observed.Immunohistochemically,leiomyomas showed diffuse positivity for α-SMA(98.8％)and desmin(99.3％),gastrointestinal stromal tumors(GISTs)expressed CD117(99.4％),DOG1(97.6％),and CD34(97.0％),and schwannomas were positive for S-100(93.7％).The predominant tumor types were leiomyomas(54.1％)and GISTs(33.7％),while the remaining 12.2％comprised other rare types.Various endoscopic resection techniques were employed based on the tumors' anatomical depth,including endoscopic submucosal dissection(ESD,40.5％),submucosal tunneling endoscopic resection(STER,17.1％),endoscopic mucosal resection(EMR,16.5％),endoscopic full-thickness resection(EFTR,13.9％),and endoscopic submucosal excavation(ESE,12.0％).EMR and ESD were primarily used for superficial lesions,while deeper tumors with were more often treated with STER,EFTR,and ESE.The rate of negative resection margins was lower in GISTs(72.2％)and other tumors with indistinct margins,compared to leiomyomas(92.6％)and those with well-defined boundaries.Conclusion Leiomyomas and GISTs are the most common gastrointestinal mesenchymal tumors resected via endoscopy.A variety of resection techniques are applicable depending on tumor location and depth.Accurate pathological diagnosis should be based on HE morphology,supplemented by endoscopic findings,margin status,immunohistochemistry,and necessary molecular tests.

Purpose To characterize the clinicopathological features of gastrointestinal mesenchymal tumors(GMTs)resected via endoscopic techniques.Methods A retrospective analysis was conducted on 495 cases of endo-scopically resected GMTs.Clinical information,histomorphological findings,immunohistochemical profiles,and mo-lecular characteristics were reviewed.Results The cohort included 495 patients aged 20-78 years(median:53 years).The majority of tumors were located in the stomach(58.8％)and esophagus(36.8％).Histologically,most tumors consisted of spindle cells,with a minority composed of epithelioid cells;fibrocollagenous or myxoid stroma was occasionally observed.Immunohistochemically,leiomyomas showed diffuse positivity for α-SMA(98.8％)and desmin(99.3％),gastrointestinal stromal tumors(GISTs)expressed CD117(99.4％),DOG1(97.6％),and CD34(97.0％),and schwannomas were positive for S-100(93.7％).The predominant tumor types were leiomyomas(54.1％)and GISTs(33.7％),while the remaining 12.2％comprised other rare types.Various endoscopic resection techniques were employed based on the tumors' anatomical depth,including endoscopic submucosal dissection(ESD,40.5％),submucosal tunneling endoscopic resection(STER,17.1％),endoscopic mucosal resection(EMR,16.5％),endoscopic full-thickness resection(EFTR,13.9％),and endoscopic submucosal excavation(ESE,12.0％).EMR and ESD were primarily used for superficial lesions,while deeper tumors with were more often treated with STER,EFTR,and ESE.The rate of negative resection margins was lower in GISTs(72.2％)and other tumors with indistinct margins,compared to leiomyomas(92.6％)and those with well-defined boundaries.Conclusion Leiomyomas and GISTs are the most common gastrointestinal mesenchymal tumors resected via endoscopy.A variety of resection techniques are applicable depending on tumor location and depth.Accurate pathological diagnosis should be based on HE morphology,supplemented by endoscopic findings,margin status,immunohistochemistry,and necessary molecular tests.