PREINVASIVE DISEASE OF THE VULVA
ESSENTIALS OF DIAGNOSIS
Possibly 1–2% of young women with cervical dysplasia have multifocal disease that tends to involve the upper third of the vagina and the vulva, perineum, and perianal areas—these surfaces arising from a common cloacogenic origin.
A spectrum of disease may be found ranging from mild dysplasia to carcinoma in situ. Involvement may not be appreciated without careful inspection with and without the green colposcopy filter. Clinically, the appearance of vulvar intraepithelial neoplasia can be quite variable.
Lesions are typically white and hyperkeratotic but may also appear gray, pink, or brown.
Colposcopy and biopsy of any suspicious lesion should be performed and are considered the gold standard for diagnosis.
An abnormal vascular pattern is most frequently associated with a severe degree of dysplasia, carcinoma in situ, or early invasive disease.
The vulvar skin is 1 component of the anogenital epithelium, extending from the distal vagina to the perineum and perianal skin. The lower genital tract epithelium is of common cloacogenic origin. Neoplasia of the vulvar skin is often associated with multiple foci of dysplasia in the lower genital tract. A strong association exists between sexually transmitted diseases and vulvar intraepithelial neoplasia (VIN), primarily human papillomavirus (HPV), and also human immunodeficiency virus (HIV). Approximately 90% of VIN lesions are positive for HPV; multicentric VIN is primarily associated with high oncogenic risk HPV subtypes such as types 16, 18, and 31, whereas vulvar condylomata and low-grade VIN are frequently associated with low-risk HPV subtypes 6 and 11. Other risk factors include smoking and other genital precancers or cancers. VIN can also be classified into viral and nonviral etiologies. Younger women are more commonly affected by viral VIN than older women and are also more likely to exhibit multifocal disease. The incidence of VIN has increased over the past decade due to the increased incidence of HPV infections in young women. The incidence of vulvar carcinoma has increased as well but at a relatively slower rate. The long-term risk of malignant transformation of treated VIN III has been estimated at 3.4–7%, and the risk for progression of untreated VIN is thought to be higher.
Premalignant lesions of the vulva occur in both premenopausal and postmenopausal women, with the median age being approximately 40 years. The average age is shifting toward younger women, with 75% of lesions occurring during the premenopausal period. There is no racial predisposition to VIN, and the disease process is often asymptomatic. The most common presenting symptom is pruritus, which is seen in > 60% of patients with VIN. The diagnosis is made by careful inspection of the vulvar area followed by biopsy of suspicious lesions.
Previously, the standard for reporting of vulvar dysplastic lesions was to classify VIN according to the degree of epithelial cellular maturation, with VIN I defined as immature cells ...