Vulvar squamous cell carcinoma and papillomaviruses: two separate entities?

Vulvar squamous precancers (vulvar intraepithelial neoplasia) are associated with sexual factors, cigarette smoking, and human papillomaviruses. However, epidemiologic studies of invasive carcinoma of the vulva have produced conflicting evidence for these associations, in part because of a strong association with vulvar inflammatory disease (dystrophies) in older women. We analyzed a series of 42 vulvar invasive carcinomas for papillomavirus nucleic acids by deoxyribonucleic acid-deoxyribonucleic acid in situ hybridization and correlated their presence with age, smoking history, and morphologic type. The carcinomas were divided into well-differentiated, moderately and poorly differentiated, and intraepithelial-like growth patterns, the latter composed of nests of invasive neoplastic epithelium with preserved cell polarity, similar to intraepithelial disease. Of the lesions studied, 28% were human papillomavirus deoxyribonucleic acid-positive. Intraepithelial-like neoplasms segregated in women with a younger mean age (64 versus 73 years) than that of women with conventional squamous cell carcinoma and they more frequently had a history of cigarette smoking (88% versus 28%). Moreover, intraepithelial-like lesions contained human papillomavirus nucleic acids more frequently (67% versus 13%) when analyzed by in situ hybridization. These observations confirm the diverse nature of vulvar squamous cell carcinoma and may explain in part why conflicting results are obtained from studies investigating the role of sexual and viral factors in the genesis of vulvar cancer. They suggest that many invasive vulvar cancers may not be linked to papillomaviruses.