S状結腸癌の内視鏡診断

Endoscopic Diagnosis of Carcinoma of the Sigmoid Colon

　S状結腸の癌が特に問題とされる理由としては，全大腸癌中に占めるこの部の癌の頻度が直腸に次いで高いことがまず挙げられよう．

　さらに診断という観点からは，この部はX線検査では腸管相互の重なり，屈曲等のため小さい病変，特に隆起性のものはしばしば見落とされる危険があって，比較的診断が難しいということがある．

　Surgical materials of colorectal carcinoma (209 lesions in total) were studied to know the gross morphological features of sigmoid carcinoma in comparison with those of cancers in other segments of the bowel: In each segment, majority of the lesions were ulcerative (Borrmann 2 or 3), but the incidence of Borrmann 3 type lesions was significantly lower (17.8%) in the sigmoid than in the other segment (about 35%) (Table 1).

　With these materials, other findings, such as extent of circular infiltration (Table 2) or presence of satellite lesions (Table 3) were also studied, but no features specific to the sigmoid carcinoma were found.

　Analysis of endoscopic findings in 29 cases of sigmoid carcinoma (5 cases of the rectosigmoid and 24 cases of the proximal sigmoid colon) (Table 4) suggested that, if an ulcerative lesion was not sufficiently visualised, the distal part of the marginal protrusion ended to be diagnosed as polypoid lesions, and that non-encircling lesions tended to be interpreted as having encircling infiltration (Table 5). However, the ulcerative nature of lesions was correctly diagnosed in most cases (15/19) of Borrmann 2 or 3 cancer, and all the polypoid cancer cases were diagnosed correctly as such. It can be stated, therefore, that gross features of the lesions are considerably well visualised by endoscopy.

　The authors' opinion is expressed on the most efficient method of diagnosing colonic carcinoma, including carcinoma of the sigmoid: Following rigid sigmoidscopy, fibrescopy of the sigmoid be performed in as many cases as possible. Then Ba-enema and fibrescopy of the entire colon should be performed.