CLINICAL GUIDELINESCMEACG Clinical Guideline:Diagnosis and Management ofGastrointestinal Subepithelial LesionsBrian C.Jacobson,MD,MPH,FACG',Amit Bhatt,MD2,Katarina B.Greer,MD,MS3,Linda S.Lee,MD4,Walter G.Park,MD,MS5Bryan G.Sauer,MD,MSc,FACG6 and Vanessa M.Shami,MD,FACG6Subepithelial lesions(SEL)of the Gl tract represent a mix of benign and potentially malignant entities including tumors,cysts,or extraluminal structures causing extrinsic compression of the gastrointestinal wall.SEL can occur anywhere alongthe Gl tract and are frequently incidental findings encountered during endoscopy or cross-sectional imaging.This clinicalguideline of the American College ofGastroenterology was developed using the Grading of Recommendations Assessment,Development,and Evaluation process and is intended to suggest preferable approaches to a typical patient with a SELbased on the currently available published literature.Among the recommendations,we suggest endoscopic ultrasound(EUS)with tissue acquisition to improve diagnostic accuracy in the identification of solid nonlipomatous SEL and EUSfine.needle biopsy alone or EUS fine-needle aspiration with rapid on-site evaluation sampling of solid SEL.There is insufficientevidence to recommend surveillance vs resection of gastric gastrointestinal stromal tumors(GIST)<2 cm in size.Owing totheir malignant potential,we suggest resection of gastric GIST >2 cm and all nongastric GIST.When exercising clinicaljudgment,particularly when state ments are conditional suggestions and/or treatments pose significant risks,health-careproviders should incorporate this guideline with patient-specific preferences,medical comorbidities,and overall healthstatus to arrive at a patient-centered approach.SUPPLEMENTARY MATERIAL accompanies this paper at http://inks.lww.com/AJG/C798Am J Gastroenterol 2023:118:46-58.https://doi.org/10.14309/ajg.0000000000002100:published online September 6.2022INTRODUCTIONfindings.However,dependingon their location and size,some mayThe term subepithelial lesion (SEL)is used to describe a mass orcause symptoms such as dysphagia,overt or occult gastrointestinalmass-like structure that typically projects into thegastrointestinal(GI)bleeding,and chronic anemia.Because the location of SEL(GI)lumen and arises from a nonmucosal layer within the GItypically precudes making a diagnosis through simple mucosaltract wall.Structures adjacent to the GI tract can also cause ex-biopsies,they often present a diagnostic challenge.Nonetheless,trinsic compression that mimic the appearance of SEL duringthrough a combination of characteristic radiographic,endoscopic,endoscopy.Historically,SEL were termed"submucosal"becauseand endosonographic appearances,coupled with judicious useof their origin under the mucosa.With the introduction of en-of EUS-guided sampling,a definitive diagnosis can be made indoscopic ultrasound(EUS),endoscopists gained the ability tomost cases(Table 1).In some clinical situations(e.g.GI bloodlossdistinguish dist
