遡及的検討が可能であった小さなS状結腸pm癌の1例

Retrospective Analysis of a Small Advanced Cancer of the Sigmoid Colon, Report of Case

要旨　患者は57歳，女性．横行結腸進行癌の手術から約2年後，経過観察のための注腸X線検査で，S状結腸に大きさ8mmのⅡa＋Ⅱc様の形態を呈する大腸癌を発見し，S状結腸切除術を行った．術前の注腸X線側面像では丈の低い台形状変形を呈し，組織学的には，pmに浸潤した腺腫成分を含まない高分化型腺癌であった．また，この病変は2年前の注腸X線像では，弧状の側面変形を伴う無茎性の隆起として描出されていた．今後，無茎性病変，特に中心陥凹を伴うものは，10mm前後でも進行癌の可能性を考慮に入れる必要があると考えられた．また，X線像では，側面変形の形態だけでなく，変形の程度まで考慮することにより，正確な深達度診断への可能性が示唆された．一方，内視鏡像では，空気量の増減でみられる空気変形の所見が深達度診断上重要と思われた．

　A 57-year-old woman, who underwent partial colectomy two years before for an advanced cancer of the transverse colon, was found to have a flat elevated lesion with a central depression in the sigmoid colon by follow-up barium enema study.

　Sigmoidectomy was performed. The resected specimen showed a Ⅱa＋Ⅱc-like lesion, measuring 8×7 mm in size. Histologically, the lesion was well differentiated adenocarcinoma without adenomatous components, slightly invading the muscularis propriae.

　The x-ray examination two years prior to the second operation revealed a sessile lesion with arc-shaped deformity in a profile view, retrospectively. We should consider that the sessile lesion with a central depression measuring about 10 mm in size might progress to an advanced cancer. Barium enema study showed a trapezoid-shaped deformity of the lesion in a profile view, but it was not so markedly deformed. Endoscopically, the feature of the lesion was not changed by pneumatic expansion. In this case, these findings seemed to be important for evaluating the depth of invasion of the cancer.