Vaginal intraepithelial neoplasia (VAIN) is a condition that frequently poses therapeutic dilemmas for gynecologists. VAIN represents dysplastic changes to the epithelium of the vaginal mucosa, and like cervical neoplasia, the extent of disease is characterized as levels I, II, or III dependent upon the depth of involvement in the epithelial layer by dysplastic cells. While VAIN itself typically is asymptomatic and not a harmful condition, it carries a 12% risk of progression to invasive vaginal carcinoma, so accurate identification, thorough treatment, and ongoing surveillance are essential.1
VAIN is associated with high-risk human papillomavirus (HPV) infection, tobacco use, and prior cervical dysplasia. Of women with VAIN, 65% have undergone a prior hysterectomy for cervical dysplasia, which emphasizes the nondefinitive nature of such an intervention.2 These women should be very closely followed for at least 20 years with vaginal cytologic and/or HPV surveillance. High-risk HPV infection is present in 85% of women with VAIN, and the presence of high-risk HPV is a predictor for recurrent VAIN. Recurrent and persistent VAIN also is more common in postmenopausal women and those with multifocal disease.
The most common location for VAIN is at the upper third of the vagina (including the vaginal cuff). It commonly arises within the vaginal fornices, which may be difficult to fully visualize because of their puckered appearance, redundant vaginal tissues, and extensive vaginal rogation.
A diagnosis of VAIN is typically obtained from vaginal cytology which reveals atypical or dysplastic cells. Such a result should prompt the physician to perform vaginal colposcopy and directed biopsies. Comprehensive visualization of the vaginal cuff can be limited in cases where the vaginal fornices are tethered, deeply puckered, or when there is significant mucosal rogation.
The application of 4% acetic acid or Lugol’s iodine are techniques that can enhance the detection of dysplastic vaginal mucosa. Lugol’s iodine selectively stains normal, glycogenated cells, and spares dysplastic glycogen-free cells. The sharp contrast between the brown iodine-stained tissues and the white dysplastic tissues aids in detection of dysplastic areas.
If colposcopic biopsy reveals low grade dysplasia (VAIN I) it does not require intervention, and has a very low rate of conversion to invasive vaginal carcinoma. However moderate- and high-grade vaginal dysplastic lesions should be treated because of the potential for malignant transformation.
Options for treatment of VAIN include topical, ablative, and excisional procedures. Observation also is an option but should be reserved for patients who are closely monitored with repeated colposcopic examinations, and probably should best be reserved for patients with VAIN I or II lesions.
The most common excisional procedure employed for VAIN is upper vaginectomy. In this procedure, the surgeon grasps and tents up the vaginal mucosa, incises the mucosa without penetrating the subepithelial tissue layers such as bladder and rectum. The vaginal mucosa then is carefully separated from the underlying endopelvic fascial plane. The specimen should be oriented, ideally on a cork board, with pins or sutures to ascribe margins and borders. Excision is best utilized for women with unifocal disease, or those who fail or do not tolerate ablative or topical interventions.