Colitis associated dysplasia in IBD
• Dysplasia can be flat or form a mass (dysplasia-associated lesion or mass [DALM]). Dysplasia in UC is graded as negative, indefinite, low grade, or high grade.
• The differential diagnosis of DALM is sporadic adenoma. The distinction between the two is difficult and requires clear communication between the pathologist and the endoscopist. If the lesion is isolated from the areas affected by colitis, then the diagnosis is usually a sporadic adenoma. A DALM lesion shows foci of dysplastic epithelium associated with areas of colitis. The pattern of dysplasia may not be uniform. Positive staining with beta-catenin may help in these cases that are negative for p53. Both DALM of any grade and flat, high-grade dysplasias are associated with the increased risk of invasive adenocarcinomas; total colectomy is usually recommended in UC cases.