Human papillomavirus infection and cervical intraepithelial neoplasia: histopathology and DNA content

To evaluate the reliability of diagnostic criteria for separating intraepithelial squamous lesions into low- and high-risk categories, 25 lesions of the cervix were diagnosed as flat condyloma, atypical immature metaplasia, or cervical intra-epithelial neoplasia with koilocytosis based on well-defined histologic criteria. The presumption was that flat condyloma and atypical immature metaplasia would be diploid/polyploid as compared to low-grade cervical intraepithelial neoplasia, which should be aneuploid. Using the major histologic parameter of the presence or absence of abnormal mitoses to distinguish the low- and high-risk lesions, it was found that all of five typical flat condylomas were diploid/polyploid and seven of eight atypical immature metaplastic lesions were diploid/polyploid; 11 of 13 cervical intraepithelial neoplasms with koilocytosis, however, were aneuploid. An additional histologic parameter of anisocytosis (variation in nuclear size) appeared much less reliable for segregating these lesions than the nature of the mitoses. Lesions for which ploidy values were particularly difficult to predict were extremely well-differentiated koilocytotic lesions with occasional abnormal mitoses. Whether these are true polyploid lesions in which the abnormal mitoses are a response to the virus, or whether they are very early aneuploid lesions that cannot be confirmed by microspectrophotometry, remains to be determined.