The diagnosis of noninfiltrative carcinomas (intraepithelial carcinoma, respectively intramucosal adenocarcinoma) is based on the existence of architectural modifications of the stratified squamous epithelia (the skin included) and of glandular structures. The architectural alterations are associated with cellular, respectively nucleo-cytoplasmic changes. The most useful cellular modifications for the diagnosis of the noninfiltrative malignant process of epithelial origin are: the cellular pleomorphism (anisocytosis and especially anisokaryosis), large nuclei in comparison with cell dimensions determining modifications of the nucleo-cytoplasmic ratio, the presence of hypertrophic nucleoli, respectively giant and/or multiple nucleoli with the change of the nucleolo-nuclear ratio in favour of the nucleolus, a large percentage of mitoses (more than 20 mitoses per thousand cells), respectively more than 4 mitoses in the microscopic field at a high magnification.