大腸の極微小陥凹型腫瘍の1例

Ultra-minute Depressed Neoplastic Lesion of the Sigmoid Colon, Report of a Case

要旨　陥凹型早期大腸癌の報告は最近多く認められるが，陥凹型腺腫の報告は現在までほとんどない．われわれは1mmの大きさの軽度陥凹の腫瘍性病変を発見，治療したので報告する．患者は48歳男性．人間ドックのS状結腸内視鏡で小さな淡い発赤で発見され，質的観察により境界不整な陥凹性病変として認識された．辺縁の正常粘膜の軽度隆起を伴っていた．strip biopsyで切除し実体顕微鏡により病変を確認し連続切片を作製，組織学的検索を行った結果，1切片でわずか10個程度の異型腺管であり，間質にリンパ球浸潤を伴っていた．形態的にⅡc型早期癌に類似しており，このような境界不整な陥凹性病変が大腸癌の発生，発育進展においてどのような役割を果たすのか，今後の症例の集積が必要である．

　Although there have been many reports on depressed type early colorecal cancer recently, no single report on depressed adenoma has ever been made. We present here a patient with a slightly depressed neoplastic lesion measuring 1 mm in size in the sigmoid colon.

　The patient was a 48-year-old man who underwent extensive clinical check-ups including sigmoid fiberscope examination, which revealed a small red-tinged spot. Close observation revealed that this lesion was depressed, bordered by irregular margin and surrounded by slightly elevated normal membrane. The lesion was removed by strip biopsy and confirmed by dissecting microscopic examination.

　Serial sections were then made for histological examination, which revealed that the lesion was composed of only 10 atypical glands with invasion of lymphocytes in the stroma. It resembled to Ⅱc type early cancer morphologically. It is necessary to accumulate cases of this kind to gain more insights regarding histogenesis, growth, and progression of colorectal cancer.