大腸鋸歯状病変の病理

Pathology of the Colorectal Serrated Lesions

要　旨

2019年に刊行されたWHO分類第5版における鋸歯状病変の分類にもとづき，過形成性ポリープ（HP），広基性（無茎性）鋸歯状病変（SSL），鋸歯状腺腫（TSA），分類不能鋸歯状腺腫（unclassified SA），鋸歯状ポリポーシス（SP），炎症性腸疾患関連鋸歯状病変（SECおよびIBD-associated serrated dysplasia）について，それぞれ各組織型の定義，病理学的特徴，系譜，鑑別点，診断・分類上の問題点などを解説する。近年では，分類不能鋸歯状腺腫が再検討され，serrated tubulovillous adenoma（sTVA），superficially serrated adenoma（SuSA），tubuloserrated adenoma（TubSA）といった新たなサブタイプも提唱されている。

　In this review, based on the WHO classification of the digestive tumours 5th edition, histological definition, pathological characteristics, history, differential diagnosis, and diagnostic problems are described for hyperplastic polyp (HP), sessile serrated lesion (SSL), traditional serrated adenoma (TSA), unclassified serrated adenoma (unclassified SA), serrated polyposis (SP), inflammatory bowel disease-associated serrated lesion (serrated epithelial change, SEC; and IBD-associated serrated dysplasia). Recently, new histological subtypes such as serrated tubulovillous adenoma (sTVA), superficially serrated adenoma (SuSA), and tubuloserrated adenoma (TubSA) were proposed from the lesions by the revision of the unclassified SA.