carcinoma in situ /insit″o̅o̅, insī″to̅o̅/ [Gk, karkinos + oma + L, in position] , a premalignant neoplasm that has not invaded the basement membrane but shows cytological characteristics of cancer. Such neoplastic changes in stratified squamous or glandular epithelium frequently occur on the uterine cervix and in the anus, bronchi, buccal mucosa, esophagus, eye, lip, penis, uterine endometrium, and vagina. Also called cancer in situ, intraepithelial carcinoma, preinvasive carcinoma. See also erythroplasia of Queyrat.
