下部消化管非上皮性腫瘍のEUS診断―そのほかの粘膜下腫瘍を含めて

EUS Diagnosis of Non-epithelial Tumors and Other Submucosal Lesions of the Lower Digestive Tract

要旨　消化管非上皮性腫瘍の多くは粘膜下腫瘍の形態をとる．脂肪腫やリンパ管腫のように特徴的な内視鏡所見を示す病変の診断は容易であるが，充実性腫瘍の診断は困難である．非上皮性腫瘍以外に粘膜下腫瘍の形態をとるものとして，カルチノイド，大腸癌（原発性，転移性）のほか，非腫瘍性病変も含まれる．これらの病変は粘膜に覆われているため生検での確定診断が難しく，断層像を評価できるEUSは有用な診断法である．エコーレベルと局在に基づいて質的診断の推定が可能であり，内視鏡治療の適応判定や計測による治療効果判定にも用いることができる．本稿では多彩な粘膜下腫瘍のEUS所見について，自験例96例と報告例に基づいて記載した．

　Non-epithelial tumors of the gastrointestinal tract usually appear as SMT（submucosal tumors）. Lipomas and lymphangiomas are easily diagnosed from their characteristic endoscopic appearances ; solid tumors are, however, difficult to diagnose due to the lack of characteristic appearances. Besides non-epithelial tumors, carcinoid tumors, some special types of cancers, and various non-neoplastic lesions also appear as SMT. Being covered with epithelium, it is difficult to make the diagnosis by endoscopic biopsy. Cross-sectional ultrasonographic images of SMTs can be obtained by EUS. EUS findings including echo revels, heterogeneity, and intramural localization of lesions contribute to qualitative diagnosis, selection of therapy and evaluation of therapeutic effects. In this article, EUS findings of various SMTs are reviewed based on our 96 cases and previous reports.