 The histopathological evaluation will be performed twice, by two different pathologists, at each participating centre. The pathologists were recruited according to their expertise in digestive histology. For the purposes of this study, they will be blinded to the assessment of the endoscopist when analysing biopsy samples. The inflammation activity level of each specimen will be ranked into the following categories: no inflammation, mild to moderate inflammation or severe inflammation. Dysplasia will be classified according to the new Vienna classification 21. Lesions classified as indefinite for neoplasia with no differentiation between adenoma and colitis-associated dysplasia in biopsy material will be not considered as neoplastic. The final histopathology findings will then be compared with the endoscopic assessment with regards to the presence of intraepithelial neoplasia and colorectal cancer. 