早期胃癌診断の実際―ひだ集中のない陥凹性病変：内視鏡所見

Basic Endoscopic Diagnosis and Pitfalls to Beware of Depressed Type Intramucosal Early Gastric Cancer without Fold Convergence

要旨　ひだ集中のない病変は，ひだ集中という指標がないため，ひだ集中を有する病変より発見が困難である．また，m癌はsm癌より一般には所見に乏しく診断上ピットフォールに陥りやすい．本稿ではひだ集中のない陥凹型m癌と鑑別上ピットフォールとなりやすい非癌症例の内視鏡所見を対比して述べた．ひだ集中のない陥凹型m癌の基本的内視鏡所見として，①辺縁不整な陥凹領域，②色調の変化（多くは発赤．同色調，褪色調変化のこともある），③陥凹周囲の辺縁隆起，④陥凹面の変化（胃小区消失，微細顆粒化，小結節上変化など），⑤純粋陥凹型とは言えないが，未分化型癌の初期にみられる胃小区の不整腫大と不整溝状変化が挙げられた．

　It is more difficult to find depressed type early gastric cancer without fold convergence than that with fold convergence by endoscopy, because the lesion without fold convergence has no distingushing signs by which it can be easiy recognized. As depressed type intramucosal gastric cancer usually has less definite signs compared to that of submucosal cancer, it involves more pitfalls for endoscopic diagnosis. We discussed comparatively the endoscopic differential diagnosis of depressed type intramucosal gastric cancers without fold convergence and of non-cancerous lesions such as benign erosive lesions, mucosal atrophy and MALT-lymphoma. We concluded that the basic endoscopic findings of depressed type intramucosal cancer without fold convergence were as follows: (1) Shallow depression with margical encroachment. (2) Change in mucosal color (mostly reddened) . (3) Marginal elevation around the depression. (4) Changed surface structure of the depression such as fine granularity, modularity and/or absence of the area gastricae. (5) Groove-like depression with uneven nodular area gastricae in diffuse type cancer.