CANCER OF THE EXTERNAL GENITALIA
Cancer of the external genitalia is rare. Squamous cell carcinoma of the cervix and external genitalia may complicate dyskeratosis and congenital ectodermal dysplasia. Vulval carcinoma may complicate vulval lichen sclerosis (which can occur rarely as a familial condition, Vanin et al. 2002). Vulval neoplasia is generally “nongenetic” and is associated with HPV infection and smoking (Daling et al. 2002; Engelman et al. 2003). There is a possibility that genetic polymorphisms in genes altering susceptibility to cancer in smokers may also alter susceptibility to vulval and anal cancer. It can arise in Paget disease of the vulva and in Bowen disease of the vulva.
Paget disease of the vulva is a rare intraepithelial cancer of the apocrine glands and is occasionally associated with an underlying adenocarcinoma (Tinari et al. 2002). Chromosomal 11p abnormalities have been described in the latter. Abnormalities of the PRAD1 gene and TP53 have been described in vulval carcinomas. Vulvar carcinoma occurs with increased frequency in Fanconi anemia (FA) and Morris syndrome. It appears that this increased prevalence in FA patients may be related to an increased susceptibility to HPV, and in FA patients an increased proportion of patients with FA and squamous cell carcinoma of the vulva are homozygous for Arg72, a p53 polymorphism that is thought to be associated with increased susceptibility to HPV infection (Kutler et al. 2003).
Primary malignant melanoma of the vulva is the second most common vulvar malignancy, an aggressive cancer, usually occurring on non-hairy skin, thus non-ultraviolet (UV) light associated (Ragnarsson-Olding 2004). A family history of cutaneous melanoma is found in 15 % of cases, and a germline mutation in the melanocortin type 1 receptor has been described in one case (Wechter et al. 2004).