Minimum extension and appropriate topographic position of tissue destruction for treatment of cervical intraepithelial neoplasia.

Minimum extension and topographic position of tissue destruction for treatment of cervical intraepithelial neoplasia (CIN) is determined by the extension and the localization of the pathologic epithelium. In 65 cone specimens, we studied the depth of CIN II crypt involvement and the linear extent and topographic position of the CIN III lesions. The topographic position of the CIN III lesion was related to a reference point R, the most caudal point of the ectocervix. The mean maximum depth of CIN III crypt involvement appeared to be 1.6 +/- 1.0 mm, and the mean linear extent of the CIN III lesion was 7.4 +/- 3.7 mm. The distal border of the CIN III lesion was located at a mean distance of 8.2 +/- 4.4 mm from the reference point R, and the proximal border at a mean distance of 13.3 +/- 3.7 mm. Taking the mean + 2 SD values as directives (97.7% of the population) suggests that in almost all patients, the depth of crypt involvement did not exceed 3.6 mm; the linear extent of the CIN III did not exceed 14.8 mm. Furthermore, this implies that in almost all patients, the CIN III lesion was located between 0.6 mm distally (mean - 2 SD) and 20.7 mm proximally (mean + 2 SD) from the reference point R. Based on these results, we conclude that minimum local tissue destruction for treatment of CIN should have a depth of 4 mm over a distance of 15 mm, and should be localized at least between 1 mm distally and 21 mm proximally from the most caudal point of the ectocervix.