Vaginal Dysplasia: Causes, Detection, and Treatment

Vaginal dysplasia, clinically known as vaginal intraepithelial neoplasia (VaIN), refers to abnormal cell changes in the lining of the vagina that are not yet cancer but can, in some cases, progress to it. Nearly all cases are driven by persistent infection with high-risk strains of human papillomavirus (HPV), and the condition shares many risk factors with cervical dysplasia. Because it is rarer and harder to detect than its cervical counterpart, vaginal dysplasia often flies under the radar, sometimes turning up incidentally during follow-up for cervical abnormalities or after a hysterectomy.

What Causes Vaginal Dysplasia

HPV is the dominant cause. High-risk HPV strains were found in over 90 percent of vaginal high-grade lesions in one study comparing vaginal and vulvar disease, making HPV positivity far more common in vaginal dysplasia than in vulvar dysplasia.¹ The same high-risk strains responsible for cervical cancer, especially HPV 16 and 18, are the main culprits here. And because the cervix, vagina, and vulva share mucosal tissue exposed to the same viral environment, women who have had cervical dysplasia or cervical cancer are at elevated risk for vaginal lesions as well.²

Beyond HPV, several other factors raise the odds. Smoking, immunosuppression (including from HIV or medications after organ transplant), and a history of multiple sexual partners all increase risk. Researchers have also found that in some cases of multicentric lower genital tract disease, the abnormal cells appear to spread from the cervix as clonal populations rather than arising independently at each site.³ That means a woman treated for cervical dysplasia can later develop vaginal dysplasia from the same transformed cells, not just from a new HPV exposure.

Grading the Abnormality

Vaginal dysplasia is graded by how deeply the abnormal cells extend into the vaginal lining. The older numbering system uses VaIN 1, VaIN 2, and VaIN 3, where higher numbers mean more severe changes. Current World Health Organization terminology groups these into two tiers: low-grade squamous intraepithelial lesions (LSIL), which covers VaIN 1, and high-grade squamous intraepithelial lesions (HSIL), which covers VaIN 2 and VaIN 3.⁴

The distinction matters because low-grade lesions behave very differently from high-grade ones. In one cohort analysis, roughly half of all VaIN diagnoses were VaIN 1, about 30 percent were VaIN 2, and 18 percent were VaIN 3.⁴ Low-grade changes frequently resolve on their own as the immune system clears the HPV infection. High-grade changes are the ones that warrant active treatment and close monitoring, because they carry the real risk of progressing to invasive vaginal cancer.

How Often It Progresses to Cancer

The reassuring news is that most vaginal dysplasia does not become cancer. A large study of over 300 women with VaIN found that roughly 87 percent of cases normalized, while about 6 percent persisted, 3.5 percent progressed, and 3.5 percent recurred after treatment. Among the small number who did develop cancer, the vast majority had started with VaIN 3.⁵ In a separate smaller study focused specifically on women with high-grade VaIN, about 12 percent eventually developed invasive cancer, with a median time to that diagnosis of around five years.⁶

So the pattern is clear: VaIN 1 is mostly a waiting game with a good prognosis, while VaIN 2 and especially VaIN 3 require intervention and ongoing surveillance. The severity of the lesion at diagnosis turns out to be the strongest independent predictor of whether it will persist or come back after treatment.⁷

Detection and Screening Challenges

Unlike cervical dysplasia, which has well-established screening protocols through Pap smears and HPV co-testing, vaginal dysplasia has no dedicated screening program. It is usually discovered in one of three ways: during follow-up colposcopy for abnormal cervical cytology, during post-hysterectomy vaginal cuff screening, or when a clinician investigates an abnormal Pap result that cannot be explained by cervical findings alone.

One reason vaginal dysplasia is tricky to catch is that cytology is not especially sensitive for it. In women with confirmed high-grade VaIN, only about 45 percent had Pap cytology results that matched the severity of the biopsy-proven lesion. More than a third had cytology that underestimated the grade, showing only low-grade changes on the Pap smear despite having high-grade disease on biopsy.⁴ This means a “mildly abnormal” result does not always tell the full story.

Colposcopy with biopsy remains the gold standard for diagnosis. During this exam, the vaginal walls are visually inspected under magnification after applying acetic acid, which makes abnormal areas turn white. Because vaginal folds can hide lesions, the exam requires careful technique and experience. Some clinicians use iodine staining (Lugol’s solution) as a complement, since normal glycogen-rich vaginal tissue absorbs the iodine and turns dark brown while dysplastic tissue does not.

Newer Diagnostic Tools

Researchers have been working on better ways to triage women and reduce unnecessary procedures. One of the more promising approaches is p16/Ki-67 dual-stain cytology, a test that looks for two molecular markers that tend to show up together when HPV is actively driving abnormal cell growth. In a prospective study, this dual-stain test detected high-grade vaginal and cervical lesions with over 91 percent sensitivity and 95 percent specificity, vastly outperforming standard Pap cytology, which caught only about 42 percent of high-grade cases.⁸ Among women who tested positive for high-risk HPV, using the dual stain as a triage step cut unnecessary colposcopy referrals by about a third.

The dual stain also shows promise for post-treatment surveillance, since it can help distinguish between a truly persistent lesion and reactive tissue changes that mimic dysplasia on standard cytology. The positivity of this biomarker has been shown to correlate strongly with the presence of high-grade lesions and with infection by HPV 16 and 18 specifically.⁹ It is not yet universally available, but its accuracy makes it a likely addition to future screening and monitoring protocols.

Topical Treatments

For women with VaIN who want to avoid surgery, or whose lesions are widespread and hard to excise cleanly, topical medications offer a real alternative. The two most studied drugs are 5-fluorouracil (5-FU) and imiquimod, both applied directly to the vaginal tissue.

5-FU is a chemotherapy agent that destroys rapidly dividing cells on contact. A meta-analysis of its use in vaginal dysplasia found that about 82 percent of women had a complete response after their first course of treatment. Recurrence occurred in roughly 16 percent of cases.¹⁰ The treatment typically involves inserting a cream into the vagina on a weekly schedule for several weeks, though protocols vary. Side effects include local irritation and ulceration, which can be significant enough that some women have trouble completing the full course.

Imiquimod works differently. Instead of killing cells directly, it stimulates the local immune response to attack HPV-infected tissue. A separate meta-analysis found that about 77 percent of women treated with 5 percent imiquimod cream had a complete response, and roughly half cleared their high-risk HPV infection entirely. The recurrence rate appeared low, with over 94 percent of responders remaining disease-free during follow-up.¹¹ Imiquimod can also cause local inflammation and discomfort, but because it works through the immune system rather than direct cytotoxicity, some clinicians view it as a gentler option.

One consensus statement on VaIN management noted that topical therapies tend to have higher recurrence rates overall compared with ablative or surgical approaches, with one review citing a recurrence or progression rate around 63 percent for topical management versus roughly 26 percent for laser ablation and 33 percent for excision.⁷ Those numbers reflect the challenge of topical therapy in real-world use: adherence matters enormously, and the vaginal anatomy, with its folds and recesses, can make uniform drug delivery difficult.

Surgical and Ablative Approaches

When topical therapy is not appropriate or has failed, or when the dysplasia is high-grade and localized, procedural treatments enter the picture. The main options are laser ablation, laser excision, and partial vaginectomy.

Carbon dioxide laser ablation vaporizes the surface layers of abnormal tissue while preserving the deeper vaginal wall. It has been a mainstay of VaIN treatment for decades. A propensity-matched study comparing laser ablation to laser excision found no significant difference in outcomes: HPV persistence was around 16 percent after ablation and 23 percent after excision, and recurrence rates were essentially the same, about 17 to 19 percent for both.¹² Plasma energy ablation, a newer alternative, has also shown comparable recurrence rates to laser ablation, suggesting that the choice of energy source matters less than the thoroughness of the procedure.¹³

One advantage of excision over ablation is that it produces a tissue specimen that a pathologist can examine. This is particularly important when there is any suspicion of invasive disease lurking beneath the surface. In a study of women who underwent upper vaginectomy (surgical removal of the upper portion of the vagina) for VaIN, 12 percent were found to have occult invasive cancer that had not been detected on biopsy beforehand.¹⁴ That finding alone makes excision or vaginectomy the preferred approach when there is any doubt about the depth of the lesion. Vaginectomy is generally considered safe, though it can affect vaginal length and may have implications for sexual function depending on how much tissue is removed.¹⁵

Pain is a practical concern with any procedural treatment. A randomized trial comparing ultrasonic surgical aspiration to laser ablation for vulvar and vaginal dysplasia found that patients treated with the ultrasonic device reported significantly less pain and, for vulvar lesions, less scarring. Recurrence overall was about 25 percent and was similar between techniques.¹⁶ The recurrence finding underscores a persistent theme: regardless of the tool used to treat VaIN, the condition has a stubborn tendency to come back.

Recurrence and What Drives It

High recurrence is the defining frustration of managing vaginal dysplasia. Multiple factors feed into it. The grade of the original lesion is the strongest predictor, with high-grade VaIN carrying roughly 3.5 times the odds of persistence or recurrence compared with low-grade disease. Multifocal disease, meaning lesions scattered across more than one area of the vaginal wall, relapses more often than a single spot. Being over 50 is an independent risk factor for recurrence after hysterectomy-related VaIN. And persistent infection with HPV 16 or 18 roughly quadruples the risk of a second recurrence.⁷

Positive HPV status after treatment is itself a red flag. In women with vaginal HSIL, HPV positivity was associated with a six-fold higher risk of vaginal recurrence.¹ This is why post-treatment monitoring typically includes HPV testing alongside cytology and periodic colposcopy, often for years.

Do You Need Screening After a Hysterectomy

This is one of the most common questions surrounding vaginal dysplasia, and the answer depends on why the hysterectomy was performed. If the uterus was removed for a benign reason like fibroids or heavy bleeding, and there was no history of cervical dysplasia, the yield of routine vaginal cuff smears is extremely low. One study following over 200 such women for an average of about seven years found that 97 percent had no cytologic abnormalities at all, and no invasive cancers were detected.¹⁷ A separate analysis found similarly low rates of abnormalities, with only low-grade changes and no high-grade or invasive disease detected in women who had hysterectomies for benign reasons.¹⁸

The picture changes completely if the hysterectomy was performed for cervical dysplasia or cancer. These women retain the vaginal tissue that was exposed to the same HPV field effect that caused their cervical disease, and they remain at meaningful risk for vaginal dysplasia. Current guidelines generally recommend continued vaginal cuff cytology and HPV testing for at least 20 to 25 years after hysterectomy for high-grade cervical disease, even if all post-surgical results come back normal. Stopping surveillance too early is one of the more consequential mistakes in this space.

The Role of the Vaginal Microbiome

An emerging area of research involves the vaginal microbiome and how it may influence susceptibility to HPV-related dysplasia. A cross-sectional study comparing women with VaIN to healthy controls found that the vaginal bacterial community in women with VaIN was distinctly different, with higher abundances of bacteria like Gardnerella and Atopobium and lower abundances of typically protective species.¹⁹ These shifts toward a less Lactobacillus-dominated environment mirror what has been observed in cervical dysplasia research, where bacterial vaginosis-associated microbiomes seem to impair local immune clearance of HPV.

Whether correcting the microbiome through probiotics or other interventions could help prevent or treat VaIN remains an open question. No clinical trials have specifically tested this for vaginal dysplasia. But the finding that the microbial environment may matter adds another dimension to understanding why some women clear HPV readily while others develop persistent lesions.

HPV Vaccination and Prevention

HPV vaccination is the most effective prevention strategy available. A systematic review examining vaccine efficacy against high-grade vulvar and vaginal dysplasia found that the vaccine was highly protective against VaIN and vulvar intraepithelial neoplasia caused by the HPV strains targeted by the vaccine. In the per-protocol population, meaning those who received all vaccine doses and were not already infected with the relevant HPV types, efficacy was 100 percent. In the broader intention-to-treat population, which included women who might already have been exposed, efficacy was about 62 percent.²⁰

The gap between those two numbers illustrates a critical point: vaccination works best before HPV exposure. This is why public health recommendations target adolescents before the onset of sexual activity. For adults who were not vaccinated as teenagers, catch-up vaccination is still available and offers some benefit, though the protection is less complete if prior HPV exposure has already occurred. Vaccination does not treat existing dysplasia, but some research suggests it may reduce recurrence rates after treatment for HPV-related disease, an area of active investigation referred to as “tertiary prevention.”

Beyond vaccination, the practical measures that reduce HPV transmission, including condom use and limiting the number of sexual partners, lower the odds of acquiring the high-risk strains that drive vaginal dysplasia. Smoking cessation is also relevant; smoking impairs local immune defenses in the genital tract and is independently associated with persistence of HPV-related precancerous lesions across all lower genital tract sites.