Vulvar Intraepithelial Neoplasia (VIN)
/Here’s the RoshReview Question of the Week!
A 41-year-old woman, G2P2, presents to your office for postcoital bleeding. She has a history of laparoscopic hysterectomy for persistent cervical intraepithelial neoplasia 3. A vaginoscopy is performed and shows multiple lesions in the upper third of the vagina. One lesion located within a suture recess near the vaginal cuff is not able to be visualized in its entirety. Biopsy reveals a high-grade squamous epithelial lesion. Her social history is significant for smoking. Which of the following is the best therapy?
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What is Vulvar Squamous Intraepithelial Lesions (SIL) and why do we care? - previously called VIN
VIN is increasingly common - esp in women in their 40s
VIN has increased more than 4x from 1973 to 2000!
VIN should be considered a premalignant condition
How do we classify?
Has changed a lot over time, but most recently we have used:
LSIL of the vulva - used for low grade changes that come from HPV infections (usually present as genital warts)
HSIL of the vulva - used for high grade changes that comes from HPV infections (precancerous lesions) - used to be called “usual type”
VIN, warty type
VIN, basaloid type
VIN, mixed (warty or basaloid) type
Differentiated type - from things like lichen sclerosus
The International Society for the Study of Vulvovaginal Disease ISSVD recommends these terms to unify the nomenclature of HPV-associated squamous lesions of the lower genital tract - all of these are based on histopathologic findings:
ACOG CO 675
How do we diagnose VIN?
Unfortunately, no good screening strategies
Detection usually limited to visual inspection
What does it look like?
Can vary. Most will be raised, but some can be flat
Discoloration of the skin - white, gray, red, brown, or even black
Should biopsy to make definitive diagnosis if not sure of diagnosis of something else (ie. LS)
Biopsy should be performed in postmenopausal women with apparent genital warts and in women of all ages with genital warts where topical therapies have failed
Colpo can also be useful - just remember that you need to soak the vulva in acetic acid with a gauze pad for several minutes
What do we do to treat?
Treat all vulvar HSIL (VIN usual type)
Surgery
Wide local excision should be done if there is suspected to be cancer
Can be occult invasion even if initial biopsy is vulvar HSIL
Should include gross margin of 0.5-1 cm around tissue with visible disease
May be altered to avoid injury to critical structures like clitoris, urethra, anus, or other structures
However, if lesions in critical areas, should be referred to specialist to avoid impaired psychosexual function (ie. if extensive around the perineum, reaching back to anus or around the clitoris
If clear margins in excised tissue, much lower risk of recurrence
Laser Ablation Therapy
Should be done if occult invasion is not a concern
Can be used for single, multifocal, or confluent lesions, although risk of recurrence may be higher than with excision
Colpo can help delineate lesions of margins
As with excision, 0.5-1cm margin to be treated
Remember than unlike genital warts, the entire thickness of the epithelium must be treated
Medical Therapy
Topical imiquimod 5%
Regimens that have been published include 3x/week to affected area for 12-20 weeks
Colpo assessment at 4-6 weeks
Residual lesions require surgical treatment
Surveillance
Recurrence rate is as high as 9-50% with all treatment regimens
Higher with positive margins
Lower in surgically treated patients
Follow up has been limited in most studies
However, women with Vulvar HSIL are at high risk of recurrence during their life time
If complete response to therapy and no new lesions at follow-up visits, scheduled 6 and 12 months after initial treatment should be monitored by visual inspection