Ⅱc＋Ⅱa型直腸早期癌の1例

Ⅱc+Ⅱa Type Early Rectal Cancer, Report of a Case

要旨　患者は77歳の男性．腹部不快感を主訴として来院．早期胃癌と診断され，その術前スクリーニング検査中にS状結腸内視鏡検査で，直腸S状部に平坦な微小発赤病変を発見した．胃部分切除および直腸S状部切除術を施行したが，直腸S状部の病変は3mmの中心陥凹を主体とする最大径が5mmのⅡc＋Ⅱa型早期癌で，組織学的には陥凹部に一致して高分化型腺癌を認めた．また病変内に腺腫の混在はなく，わずかにsmに浸潤していた．本例は陥凹型大腸癌のごく初期のものと考えられた．

　A 77 year-old man was admitted to our hospital because of abdominal discomfort for the past three months. Subsequent examinations revealed an early gastric cancer. As a part of routine preoperative screening, sigmoidoscopy was performed revealing a small and flat reddish lesion at 18 cm from the anal verge (Fig. 1). Biopsy specimen proved to be an adenocarcinoma. Barium enema, however, showed no definite abnormality (Fig. 2). Rectosigmoidectomy was carried out on January 20, 1986. The specimen contained a small and flat elevated lesion with slight central depression of Ⅱc+Ⅱa type, measuring 5×5 mm in diameter (Fig. 3). Cross section of the lesion showed Ⅱc type early rectal carcinoma (Fig. 4), i.e., well differentiated adenocarcinoma with submucosal invasion but without adenomatous lesion. The carcinomatous invasion was found only in the centrally depressed area with diameter of 3 mm (Fig. 5).

　Thus, the lesion was considered as Ⅱa+Ⅱc type early colorectal carcinoma.