Cytological sampling and cell morphology as evidences of the major role played by the endocervical epithelium in carcinogenesis of the uterine cervix

Rui Luzzattoa, Mathilde E. Boon, M.E.H. Polia, Laura Luzzattoa and Marta Recktenvaldb

aInstituto de Patologia de Porto Alegre, Department of Health, RGS, Brasil, bLeiden Cytology and Pathology Laboratorium, Leiden, The Netherlands.

Human Papillomavirus (HPV) infection is associated with carcinogenesis of male and female genitalia. HPV DNA sequences are equally demonstrated in both sexes and the rate of infection does not vary significantly in men and women. Cancer in sites frequently exposed to the infection, such as the mucosa of penis, vagina and vulva, occur to a much lesser frequency than epithelial neoplasia at the uterine cervix. AIM: To search for anatomical and histological factors, which favors the development of the uterine cervix cancer. METHODS: We studied the cytological samples collected of ectocervices and endocervices of 56,120 women, obtaining 112,240 smears. The samples were smeared separately in two glass slides, one for the ectocervical sample collected with an Ayre spatula and the other for the sample collected with an endocervical brush. The slides were stained with the Papanicolaou stain and examined by optical microscopy, searching for intraepithelial neoplasia and invasive cancer of the cervix. RESULTS: A total of 674 cervical intraepithelial neoplasias grades I and II (CIN I and II) were diagnosed. Of those, 299 were present in both endocervical and ectocervical samples, 236 exclusively at the endocervical sample and 139 exclusively at the ectocervical sample. 221 cervical intraepithelial neoplasias grade III (CIN III) were seen, 204 were confirmed by histological examination and 17 had no follow up. 135 CIN III were present in both samples, 83 exclusively at the endocervical smear and 3 exclusively at the ectocervical sample. 53 cases of invasive squamous cancer (ISC) were found and all confirmed histologically. 49 ISC were found in both samples, 4 in the endocervical one and none exclusively at the ectocervix. CONCLUSIONS: The prominence of neoplastic cells in the endocervical samples, strongly suggest that the original glandular epithelium and not the squamous epithelium is the major site where cervical carcinogenesis occurs. This is of utmost importance in the mass screening for the diagnosis and prevention of cancer of the cervix.

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Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Paris, France; February 9 - 12, 2002; in the section on Carcinogenesis.