[Dysplasia in ulcerative colitis].

Due to their increased risk of developing a carcinoma, patients with long-standing ulcerative colitis are usually enrolled in surveillance programs in order to regularly evaluate their risk of developing cancer using endoscopic biopsies. In this evaluation, the histologic identification of dysplasia in connection with the endoscopic findings is of central importance. According to current recommendations, dysplasia which occurs in endoscopically identifiable lesions, i.e. in the form of a DALM ("dysplasia associated lesion or mass"), result in a colectomy independent of the degree of dysplasia, as does high grade dysplasia in a flat mucosal area. For low grade flat dysplasia, the diagnosis should be confirmed. A special diagnostic challenge is the distinction of adenomas in ulcerative colitis, since for these lesions a simple polypectomy is an adequate treatment. For the assessment of the individual cancer risk various molecular biologic techniques have been discussed as additional procedures (p53, Sialyl-Tn, ploidy status by flow cytometry), but H&E histopathology is still the gold standard for the grading of dysplasia and its distinction from regenerative epithelial changes. Due to the increasing refinement of endoscopic techniques and considering the potential new, less invasive methods for treating dysplasia, changes in the management approach for patients with dysplasia in ulcerative colitis are to be expected.