早期大腸低分化腺癌の3例

Early Colorectal Poorly-differenciated Adenocarcinoma, Report of Three Cases

要旨　早期大腸低分化腺癌は希少とされている．筆者らは11年間で3病変を経験し，その臨床病理学的特徴について報告する．3病変ともに多発大腸癌症例であった．肉眼形態は，2病変で表面型腫瘍を呈し腺腫，高分化管状腺癌を伴っていたが，1病変では，発赤，びらんとして観察され，低分化腺癌のみから成っていた．深達度はいずれもSM深部浸潤癌であった．拡大観察では、3病変とも低分化腺癌部分で，pit構造は指摘し難かった．これらの病変を通して，低分化腺癌の発生に関して2つの経路の存在が示唆され，これを踏まえて内視鏡などの検索を行うことが，適切に発見・診断する一助になると考えられた．

　Early colorectal poorly-differenciated adenocarcinomas are said to be very rare. We have diagnosed and treated only 3 lesions during 11 years. Here we report the clinical and pathological characteristics of these lesions. All of the patients had experienced other colorectal cancers. Two lesions were superficial in form, and accompanied by adenoma and well-differenciated adenocarcinoma. Another lesion was observed as redness and erosion, and consisted of only poorly-differenciated adenocarcinoma. All of these lesions were submucosal deep invasive cancers. In magnifying endoscopy, the areas of poorly-differenciated adenocarcinoma were observed as Vn pit patterns. Through the consideration of these lesions, there seems to be 2 pathways involving the origin of the poorly-differenciated adenocarcinoma. Endoscopic examination with the understanding of this suggestion may lead to the detection and diagnosis of those leisions.