Nuclear DNA study of vulvar intraepithelial and invasive squamous neoplasms

In this study, 59 vulvar intraepithelial squamous neoplasms (8 atypia and 51 carcinoma in situ) and 33 invasive squamous carcinomas were analyzed for their nuclear DNA content using Feulgen microspectrophotometry. Four cases of atypia had a polyploid DNA distribution. The remaining 4 cases of atypia and all cases of carcinoma in situ had an aneuploid pattern, and nearly two thirds of these had high ploidy stem cells (greater than 3N). This is in contrast to the low ploidy stem cells (less than 3N) seen in 70% of the invasive carcinomas and in 82% of the intraepithelial neoplasms in the vicinity of invasive carcinomas. This observation suggests that not all vulvar intraepithelial neoplasms have the same propensity to become invasive. Invasive carcinomas of comparable size and depth of invasion with low ploidy stem cells had a higher frequency of lymph node metastasis than those having high ploidy stem cells. The significance of nuclear DNA findings related to gynecologic neoplasms is discussed.