HETEROGENEOUS ETIOLOGY OF SQUAMOUS CARCINOMA OF THE VULVA

Objective: To correlate various previously identified risk factors, di fferent histologic types, and the presence of human papillomaviruses ( HPV) in squamous vulvar carcinomas and intraepithelial precursor lesio ns. Methods: Cases of squamous vulvar carcinomas and intraepithelial p recursor lesions from a case-control study were analyzed by histologic type, the presence of HPV, and HPV type. These findings were correlat ed with demographic and interview data. Results: Significant differenc es (P < .001) in the prevalence of HPV DNA were noted between the foll owing: 1) patients with high-grade vulvar intraepithelial neoplasia (V IN) (48 of 54 [88.9%]), 2) different types of squamous carcinomas, des ignated basaloid and warty carcinomas (18 of 21 [85.7%]), and 3) kerat inizing squamous carcinoma (three of 48 [6.3%]). When the risk factor profiles for basaloid or warty carcinoma and keratinizing squamous car cinoma were compared, it was found that basaloid and warty carcinoma w as significantly associated with the classical cervical cancer risk fa ctors (lifetime number of sexual partners, age at first intercourse, a bnormal Papanicolaou smears, venereal warts, low socioeconomic status, and cigarette smoking) whereas keratinizing squamous carcinoma was le ss strongly linked to these factors and in some cases not at all. The risk profile for VIN was similar to that of basaloid and warty carcino ma (with respect to sexual and reproductive history and smoking), alth ough effects were weaker for some factors. Conclusion: The results of this study further support the view that vulvar carcinoma has two diff erent etiologies, one related to HPV infection and one that is not.