6年間経過観察した扁平隆起型早期RS部癌と思われる1例

Flat Elevated Early Rectosigmoidal Carcinoma Followed-up for Six Years, Report of a Case

要旨　58歳の女性で，直腸RS部の15×13mmの扁平隆起型早期癌と思われる1例を報告した．約6年間の経過観察では，隆起の形状と大きさにおいてほとんど変化はなく，11回の生検所見でも積極的な癌の診断は得られなかったが，長径が20mmであること（X線写真上計測），扁平隆起であること，の2点からcarcinoma de novoを疑い，手術した．切除標本組織所見では，明らかな癌とは診断できなかったが，肉眼所見を加味すると，carcinoma de novoとみなすかどうかが問題になる症例と考えられた．本症例については，異型度係数の計測は行っていない．adenoma-carcinoma sequenceとcarcinoma de novoの論争が盛んな折，大変興味ある症例と考えられたので報告した．

　A 58-year-old female visited our hospital for colonic examination in 1979. Laboratory examination showed no abnormalities. Barium enema and colonoscopy showed a sessile protruded lesion, 20×10 mm in size, without central depression in the rectosigmoid colon. Examination of biopsy specimens revealed a tubular adenoma with moderate atypia.

　Half-yearly follow up examination, by barium enema or colonoscopy, was conducted for six years from 1980 to 1986. The shape and size of the lesion did not change with the passage of time.

　Wedge resection was done because of suspected de novo cancer on January 31 st, 1986. Examination of the resected specimen showed a sessile protruded lesion, 15×13 mm in size.

　Histologically, it was a tubular adenoma with moderate atypia, but it was also possible to regard it a de novo cancer from the view point of its size and macroscopic findings.