Carcinoma in situ of the uterine cervix--diagnosis by biopsy.

In 50 cases of carcinoma in situ of the cervix uteri, the lesion was present in the cervical canal in 36 instances, but the squamous epithelium of the portio was involved in only 14 cases. Since single biopsy from the portio or external os may show no malignant change even in cases in which vaginal smears are positive for cancer, single biopsy is indicated only in the presence of gross suspicious lesions. When positive smears have been obtained, cold-knife cone biopsy is indicated (a) whenever gross lesions are not visible on the ectocervix, (b) if carcinoma in situ is found in a biopsy of the external os, in order to determine the presence or absence of invasion, and (c) when there are repeated positive smears and biopsy of the portio has not shown the presence of malignancy. The technique of cone biopsy is given in detail.