表在型Barrett食道癌の扁平上皮下進展

Squamous Subepithelial Spread of Superficial Barrett's Esophageal Carcinoma

要旨●Barrett腺癌は時に正常の扁平上皮下へと側方進展し（BCUS），癌が表層に露出していないため内視鏡による範囲診断が困難となる．BCUSの内視鏡所見として，WLIでは淡い発赤，NBIでは淡い茶色変化などが挙げられるが，時に不十分である．1.5％酢酸を撒布すると，BCUSはそれまで視認されなかった淡い白色変化（SWS）が観察される．病理組織では酢酸撒布で所見が得られた領域に一致して扁平上皮下の癌腺管が表層へと開口する像（rising gland）が観察される．本稿ではBarrett腺癌の扁平上皮下進展部の内視鏡的特徴であるSWSに関して自験例をもとに解説する．

　Barrett's esophageal adenocarcinoma occasionally spreads laterally under healthy squamous epithelium, and this condition is termed BCUS（Barrett's cancer under the squamous epithelium）. As cancerous cells are not present in the superficial layer in such cases, it is difficult to determine the extent by endoscopy. Endoscopic findings of BCUS include light redness on white light imaging and light brown changes on narrow band imaging. However, such findings can sometimes be insufficient to make a diagnosis. Spraying with 1.5% acetic acid enables the observation of light white changes（small white sign ; SWS）that were not previously confirmed visually in BCUS. Histopathology reveals the openings of cancerous glands into the superficial layer under the squamous epithelium（rising gland）in the area consistent with those obtained by acetic acid spraying. This thesis explains SWS, which are endoscopic findings characteristic of the area in which Barrett's adenocarcinoma spreads under the squamous epithelium, based on the report of a case that we treated.