—大腸上皮性ポリープの鑑別診断—腫瘍性ポリープ—病理診断の立場から

Differential Diagnosis of Neoplastic Colorectal Polyps:from the Perspective of Pathological Diagnosis

要旨●大腸の上皮性腫瘍性ポリープには管状腺腫，管状絨毛腺腫，絨毛腺腫，無茎性鋸歯状病変，鋸歯状腺腫，腺癌，およびこれら複数の成分から成る病変がある．近年，superficially serrated adenomaが新たな組織型として提唱されている．これらのポリープにはそれぞれ臨床的，病理組織学的，分子病理学的な特徴がある．腺腫と癌の診断基準には，診断者間のばらつきのみならず，本邦と欧米との違いも存在することは，海外の文献を参照する際に注意する必要がある．本稿では各ポリープの臨床病理学的特徴，鑑別点に加え，留意すべき診断基準の違い，分子異常と大腸癌発癌経路における意義について概説する．

　Polypoid epithelial neoplasms of the colon include tubular adenoma, tubulovillous adenoma, villous adenoma, sessile serrated lesion, traditional serrated adenoma, adenocarcinoma, and mixed lesions consisting of these components. Recently, superficially serrated adenoma has been proposed as a new entity. These polyps are characterized by distinct clinical, histopathological, and molecular biological characteristics. The diagnostic criteria and terminology for adenoma and adenocarcinoma vary among observers and between Japan and Western countries. In this article, we have outlined the clinicopathological characteristics and differential diagnosis of each polyp. Additionally, the molecular abnormalities observed in each polyp and their significance during colorectal cancer's carcinogenesis have been discussed.