结肠镜检查和黏膜活检的组织病理学评估是诊断炎症性肠病(IBD)的主要方法。克罗恩病(CD)可累及口腔至肛门的任一部位,以节段性、透壁性炎症为主要特征;溃疡性结肠炎(UC)主要表现为由直肠向上延伸至盲肠的广泛黏膜炎症,可伴有或不伴倒灌性回肠炎。缺乏慢性炎症的组织学证据如隐窝变形、固有层单核细胞浸润、基底层淋巴细胞增多时,不能诊断为CD或UC。直肠、结肠、回肠末端的结肠镜黏膜活检是区分慢性与急性黏膜炎症、评估疾病分布以及鉴别诊断CD与UC的关键。UC的诊断可能较为直观,而诊断CD需结合临床表现、内镜表现、影像学和组织病理学结果。 Histopathological assessment of colonoscopy and mucosal biopsy is the primary method of diagnosis of inflammatory bowel disease (IBD). Crohn’s disease (CD) can affect any part of the mouth to the anus, with segmental, transmural inflammation as the main feature; ulcerative colitis (UC) mainly manifested as a wide range of mucosal inflammation extending up from the rectum to the cecum , With or without reflux ileitis. Histological evidence of chronic inflammation, such as crypt degeneration, mononuclear cell infiltration of the lamina propria, and basal cell lymphocytosis, can not be diagnosed as CD or UC. Colonoscopy at the distal end of the colon, colon, and ileum is the key to differentiating between chronic and acute mucosal inflammation, evaluating disease distribution, and differentiating between CD and UC. The diagnosis of UC may be more intuitive, and the diagnosis of CD should be combined with clinical manifestations, endoscopic findings, imaging and histopathological findings.