形態変化を来した大腸癌の3例

Colorectal Carcinoma with Chronological Change in Macroscopic Shape, Report of Three Cases

要旨　短期間に形態変化を来した大腸癌3例を経験した．〔症例1〕はRsの15mmのsm癌．初回検査でIsp型，生検後にIIa＋I型，粘膜下局注後にIIa＋IIc型に変化した．〔症例2〕はRaの20mmのsm癌．初回検査でIIa型，生検・粘膜下局注後の3か月後に2型様病変に変化した．〔症例3〕はRsの15mmのmp癌．初回検査でIsp型，生検などは施行しなかったが2か月後に2型に変化した．組織学的に〔症例1，2〕では虚血像・線維化が著しく，生検・粘膜下局注による形態変化と推察された．すなわち，大腸腫瘍は虚血・線維化により短期間に形態変化しうる可能性があり，大腸癌の自然史に一考を与えるものと思われた．

　We experienced three cases of colorectal carcinoma with morphological changes for a short period.

　〔Case 1〕 The lesion was a 15 mm sized carcinoma with submucosal invasion in the rectum (Rs). Initial examination showed the lesion was Isp type, it transformed to IIa+I type after biopsies, then changed to IIa+IIc type after submucosal injection.

　〔Case 2〕 The lesion was a 20 mm sized carcinoma with submucosal invasion in the rectum (Ra). Initial examination disclosed a IIa type lesion which changed to a type 2 shaped lesion after submucosal injection and biopsies (three months later).

　〔Case 3〕 The lesion was a 15 mm sized tumor invading the muscularis propria in the rectum (Rs). At first, it was Isp type but, two months later, it changed to a type 2 shaped lesion without biopsies and submucosal injections.

　As histologic examination showed the lesions of〔Case 1 and 2〕 had remarkable ischemic change and fibrosis, those changes could be induced by biopsies and submucosal injection. In other words, it is possible for the colorectal tumor to change its form by ischemic change and fibrosis for a short period. We think that these three case are invaluable for understanding the natural history of the colorectal cancer.