colitic cancer/dysplasiaの画像診断―超音波内視鏡を中心に

Possible Roles of Endoscopic Ultrasonography in Ulcerative Colitis-associated Colorectal Cancer

要旨　EUSを行った潰瘍性大腸炎関連大腸癌7症例8病変の画像を呈示するとともにEUSの診断的意義について考察した．存在診断は全例で可能であった．M癌は限局性隆起，浸潤癌は壁深層に及ぶ不整な輪郭の低エコー領域として認識できた．癌周囲の平坦なdysplasiaは認識できなかった．質的診断はM癌では不可能であったが，浸潤癌では全例で可能であった．深達度診断は8病変中7病変で正診でき，機種を適切に選択すれば良好な診断能が得られると考えられた．EUSをサーベイランスに組み入れることは困難であるが，生検や内視鏡でdysplasiaや癌が疑われる場合には積極的にEUSを活用すべきであると考えられる．

　The possible roles of endoscopic ultrasonography（EUS）in the diagnosis of ulcerative colitis-associated colorectal cancers were described, based on our experience of eight cancers in seven cases. The existence of cancer could be recognized by EUS in all cases, but flat dysplasia surrounding cancer could not be recognized by EUS. The qualitative diagnosis of cancer was possible in invasive cancers based on the presence of a hypoechoic area with irregular contours penetrating the wall layers, but such diaghosis was impossible in mucosal cancers. The depth of cancer infiltration could be estimated by EUS when the instrument was properly chosen. Our conclusion is that EUS may have the potential to detect invasive cancers although it is difficult to incorporate EUS into cancer surveillance.