Definition

A term used to describe the presence of abnormal cells on the surface of or in the tissue that lines an organ, such as the cervix, breast, prostate, anus, vagina, vulva, penis, and mouth. The changes in the cells may be low grade or high grade, depending on how abnormal the cells look under a microscope and how much of the tissue is affected. Sometimes, the abnormal cells may become cancer and spread to nearby normal tissue. Also called intraepithelial neoplasia.