Epithelium Replacement Contributes to Field Expansion of Squamous Epithelium and Ulcerative Colitis–Associated Neoplasia

Abstract

Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by repeated destruction and regeneration of the colorectal epithelium. UC-associated neoplasia (UCAN) arises from a field of colorectal epithelial cells with a mutational burden, such as TP53 mutation caused by chronic inflammation; this is known as field cancerization. UCAN usually forms a flat dysplastic lesion that is difficult to detect by endoscopic examination.1 Squamous metaplasia is another example of a rare epithelium; it is characterized by the replacement of nonsquamous epithelium by stratified squamous epithelium and has been reported in patients with long-standing UC.