Histopathogenesis of carcinoma in situ of the uterine cervix.

Cancer of the cervix is amenable to treatment provided it is diagnosed at the preinvasive stage, and it is therefore imperative to be able to identify cases of symptomless cervical cancer, which invariably presents no visible alteration in the appearance of the mucous membrane. Fortunately, this is possible by study of vaginal smears for exfoliated cells.In view of the ease with which carcinoma of the uterine cervix can be induced in mice and of its similarity to analogous lesions in women, it was thought that study of early cytological and morphological changes in cervical carcinoma of the mouse-especially at the in situ stage-might prove valuable for biological and therapeutic studies of human cervical carcinoma.This paper reports on study of the progressive epithelial changes in the mouse cervix by means of exfoliated cells in vaginal smears and histological examination of the cervical epithelium after intravaginal painting with 3,4-benzpyrene. The authors consider that basal cell hyperplasia and the early grades of dysplasia are reversible if the carcinogenic agent is withdrawn, but that the lesion is likely to be invasive and progressive once the presence of large numbers of squamoid cells indicates that the dysplastic changes involve the superficial layers.