胃上皮下腫瘍の内視鏡診断—病変の壁内局在が粘膜下層にある疾患を中心に

Endosopic Diagnosis for Gastric Subepithelial Tumor：Focus on Diseases in which the Lesion's Intramural Localization is in the Submucosal Layer

要旨●胃上皮下腫瘍は，粘膜上皮より深部に存在する壁内病変により，粘膜が挙上されて生じた隆起の総称である．症状がないことが多く，スクリーニングの上部消化管内視鏡検査で偶然発見されることが多い．病理組織学的に病変は多岐にわたるが，GISTや平滑筋腫などの間葉系腫瘍，異所性膵，囊胞，脂肪腫などの頻度が高い．実際の臨床ではGIST診療ガイドラインに沿った対応が基本となり，小さな病変であれば経過観察とすることが多い．通常内視鏡観察での診断には限界があるが，できる限り鑑別を絞り，精査・治療のタイミングを逃さないように努めることが大切である．

　A subepithelial tumor is a general term for a mucosal elevation caused due to an intramural lesion that is deeper than the mucosa. They are often asymptomatic and are incidentally discovered during upper gastrointestinal endoscopy screenings. Lesions vary histologically, but mesenchymal tumors such as GISTs（gastrointestinal stromal tumors）and leiomyomas, ectopic pancreas, cysts, and lipomas are more frequent. The basic approach is to follow the guidelines for GIST in actual clinical practice ; moreover, small lesions are often followed up with observation. Narrowing down the differential as much as possible to avoid missing the time for close examination and treatment is important ; although, endoscopic observation is limited.