癌併存大腸SSLの内視鏡診断—画像強調観察の立場から：LCI観察

Endoscopic Diagnosis of Colorectal Cancer with a Sessile Serrated Lesion Using Linked Color Imaging

要旨●本稿では，dysplasiaまたは癌併存大腸SSLの臨床病理学的特徴，内視鏡的特徴，特にLCIの所見ついて概説する．臨床病理学的には，SSL由来の大腸癌は腺腫由来の癌とは異なる組織学的特徴を示し，脈管侵襲やリンパ節転移が高頻度であり，より高悪性度の癌へと進展していく可能性が示唆される．内視鏡所見では，①（亜）有茎性，②二段隆起，③陥凹，④発赤の4つの所見が重要である．富士フイルム社製のLCIは，白色光で画面の明るさを保ちながら，重ねて照射される狭帯域光で粘膜のわずかな色の違いを強調した画像を表示する画像強調内視鏡である．LCIは白色光よりもSSLに併存する発赤調の癌またはdysplasiaの視認性を向上させ，癌併存SSLの診断に寄与する可能性がある．

　In this article, we review the clinicopathological and endoscopic features, particularly the LCI（linked color imaging）findings, of colorectal cancer with a SSL（sessile serrated lesion）. SSL-derived colorectal cancer exhibits different histological characteristics from adenoma-derived cancers, suggesting the possibility of progressing to high-grade malignant cancer. Four important findings among the endoscopic findings of the lesions are（semi）pedunculated morphology, double elevation, depression, and reddishness. The LCI, developed by FUJIFILM Corporation, is an image enhancement function that maintains the brightness of the screen with white light while displaying an image that emphasizes the slight color difference of the mucosa with overlapping narrow-band light. Compared to white light, LCI improves the visibility of the reddened areas of cancer or dysplasia with SSL. This suggests that LCI may contribute to the diagnosis of colorectal cancer with SSL.