大腸の小さな扁平隆起性病変（small “flat elevation”）の臨床病理学的検討

Small “Flat Elevation” of the Large Bowel with Special Reference to Its Clinico-pathological Features

要旨　外科的切除標本ならびに内視鏡的ポリープ摘除標本の中から，直径1cmまでの小さな扁平隆起性病変（“flat elevation”）36病変を選出して，その内視鏡的および組織学的特徴を明らかにした，病変の内訳は軽度異型腺腫14病変，中等度異型腺腫5病変，高度異型腺腫（focal carcinoma）14病変，粘膜下浸潤癌3病変であり，大きな病変ほど異型が強い傾向が認められた．小さいにもかかわらず腺腫内癌が多いことから，これらの病変が比較的短期間に進行癌へ進展する可能性が推察され，“flat elevation”が大腸のadenoma-carcinoma sequenceに重要な役割を果たしていると考えられた．日常診療において，“flat elevation”の存在を認識することの重要性を強調した．

　From surgically and colonoscopically removed specimens 36 small “flat elevations” not more than 1 cm in diameter were collected, and their colonoscopic and histological characteristics were described. There were 14 adenomas with mild atypic, 5 with moderate atypia, 14 with severe atypia (or focal carcinoma limited to the mucosa) and 3 invasive carcinomas. The grade of atypia seemed to increase with increasing size and they were assumed to play some important role in adenoma-carcinoma sequence. The importance of recognizing the presence of such small “flat elevation” in evexy day practice was stressed.