Ulcerative colitis-related epithelial dysplasia represents a premalignant lesion, which may lead to the development of ulcerative colitis-related adenocarcinoma. The proper management of this condition requires proctocolectomy before the acquisition of the invasive phenotype. Patients with chronic ulcerative colitis, however, like the general population, may develop sporadic colorectal adenomas not related to the presence of the inflammatory bowel disease. These adenomas are also characterized by epithelial dysplasia, but their detection carries very different clinical implications. It is therefore essential to distinguish between chronic ulcerative colitis-related dysplasia and sporadic colorectal adenomas. The gross and histologic features do not provide a definite distinction between these two different types of dysplasia of the colonic epithelium. Recent developments in the molecular genetics may provide the necessary means. Int J Surg Pathol 8(1):11-16, 2000