通常内視鏡画像の成り立ち─小腸，大腸

Endoscopic Findings of Intestinal Lesions:How Are They Formed?

要旨●腸の疾患の内視鏡所見は極めて多彩であるが，基本要素は病変の色調と形態である．腫瘍性疾患の所見は腫瘍細胞の量と分布によって所見が決定されるのに対し，炎症性疾患は生体反応の結果であり，組織の変性・脱落を伴うことが多い．しかし，結果的に腫瘍性疾患と炎症性疾患で類似の所見を呈することがある．本稿ではびらん・潰瘍および隆起を形成する機序，色調変化を来す原理について概説するとともに，粘膜下腫瘤と敷石像を取り挙げて，それらの成り立ちを解説した．病変の成り立ちを理解することは，診断能の向上に寄与すると考えられる．

　The basic elements of endoscopic findings are the shapes and colors of lesions. The characteristics of neoplastic lesions are determined by the volume and distribution of tumor cells. Conversely, those of inflammatory lesions result from biological reactions and are often accompanied by the degeneration and/or loss of tissues. However, similar findings may present in both neoplastic and inflammatory lesions. In this article, we outline the mechanisms of lesion formation in erosions, ulcers, and protrusions as well as the principal causes of their characteristic colors. Furthermore, we explain the composition of submucosal tumors and lesions displaying a cobblestone appearance. The understanding of the mechanisms underlying endoscopic findings is expected to contribute toward an improvement in diagnostic ability.