Distribution of cervical intraepithelial neoplasia across the cervix is random

Objective: This study was undertaken to assess the validity of an assumption that histologically confirmed cervical intraepithelial neoplasia (CIN) lesions are not randomly distributed across the cervix. Study design: This retrospective study included 359 women ranging in age from 17-81 years (mean ± SD, 34.4 ± 12.1 years) who underwent colposcopically directed cervical biopsy. Data were examined to determine the distribution of histologic diagnosis across the cervix. The study had 80% power to detect a true, relative by-location difference. Results: Two hundred ninety (80.8%) women were classified as nondysplastic, whereas 69 (19.2%) were classified as dysplastic (CIN1, or CIN2, or CIN3). The most common location for biopsy was the 11 o'clock position (22%), whereas the least common location was the 10 o'clock position (0.8%). The most common location for dysplastic as well as nondysplastic lesion was the 11 o'clock position. No association was found between types of histologic lesion on colposcopically directed biopsy and location of lesion. Conclusion: Contrary to previous assumptions, histologically confirmed CIN lesions are randomly distributed across the cervix site.