粘膜下腫瘍様の形態を呈した進行結腸癌の1例

Colonic Cancer Resembling Submucosal Tumor, Report of a Case

要旨　82歳，男性．主訴はなし．触診にて右下腹部に腫瘤を認めたため入院した．注腸X線では上行結腸内側に7cmに及ぶ陰影欠損像と伸展不良，多数のひだ集中を認めた．内視鏡では頂部に白苔を有し，周囲粘膜は健常な隆起性病変を認めた．EUSでは腫瘍は筋層と連続性を有し，ダンベル型の形態を呈していた．画像検査からは粘膜下腫瘍を疑ったが，白苔部からの生検により腺癌の診断を得た．粘膜下腫瘍様の形態を呈した進行結腸癌と診断し手術を施行した．結果は，上行結腸癌，5型（粘膜下腫瘤型），7cm大，粘液癌を一部に有する低分化癌，深達度はsi，ly₁，v₁，n₀であった．

　An 82-year-old male was admitted for examination of right lower abdominal tumor. The barium enema examination demonstrated an irregular narrowing with poor distensibility measuring 7 cm in length in the ascending colon. Colonoscopic examination showed that there was a sessile lesion resembling a submucosal tumor. The surface of the lesion was the same as that of the surrounding mucosa and a central depression with whitish exsudate was observed on the top of the lesion. EUS showed that the tumor was a homogeneous low echoic lesion in the proper muscle layer and seemed to be dumbell in shape. Biopsy specimens that were taken from the ulceration contained adenocarinoma cells. We diagnosed the tumor as being advanced asending colonic cancer resembling submucosal tumor. The patient underwent an operation. Histologically, it proved to be a poorly differentiated adenocarcinoma type 5, part of which was mucinous carcinoma, in the ascending colon. It was 7 cm in diameter with a depth si, ly1, v1, n0.