十二指腸の非腫瘍性ポリープの内視鏡所見

Endoscopic Diagnosis of Non-neoplastic Duodenal Protuberant Lesions

要旨●十二指腸に生じる非腫瘍性隆起性病変は比較的多彩な形態を呈するため，通常の内視鏡観察のみによる質的診断は容易ではない．また，限局性の非腫瘍性隆起性病変のうち，特徴的な病理組織像を有するものは腫瘍様病変と呼ばれ，腺癌の前駆病変ないし胃型腫瘍の発生母地である可能性が指摘されている．今回は，頻度の高い異所性胃粘膜やBrunner腺過形成に加え，胃上皮化生，胃腺窩上皮型過形成性ポリープ，muco-submucosal elongated polyp，リンパ管腫，Peutz-Jeghers型ポリープや異所性膵についてNBI併用拡大観察所見も含め内視鏡像を中心に概説する．十二指腸上皮性腫瘍との鑑別診断を考えるうえで，それらの病態や特徴を理解することは重要である．

　Non-neoplastic protuberant lesions in the duodenum have a wide variety of morphologies ; therefore, accurate diagnosis is challenging only on the basis of conventional endoscopic features. In recent years, tumor-like lesions have gained attention as a precursor lesion of adenocarcinoma or as a lesion where a gastric-type tumor originates. Here, we review the endoscopic findings, including magnifying endoscopy with narrow-band imaging for non-neoplastic protuberant lesions, such as gastric metaplasia, foveolar epithelial type of hyperplastic polyps, mucosubmucosal elongated polyp, lymphangioma, Peutz-Jeghers type polyp, and heterotopic pancreas in addition to Brunner's gland hyperplasia and heterotopic gastric mucosa that are most commonly identified in the duodenum. Comprehensive information about the characteristics of non-neoplastic protuberant lesions is essential for differential diagnosis.