Introduction
Vulvar lichen planus (LP) is an inflammatory disorder that affects mucocutaneous tissues, including vulva, vagina and other non-genital regions, such as oral mucosa, skin and esophagus. LP has an estimated prevalence of 0.5-3.7%, with erosive LP being the most prevalent form. The etiology of this condition is still not fully understood, but it is considered to be an autoimmune disease with a T-cell-mediated pathogenesis, with a possible role for some exogenous factors, such as nonsteroidal anti-inflammatories and antihypertensive drugs.1
Vulvar squamous cell cancer (VSCC) can arise from two independent premalignant pathways: a) one HPV related (30-50% of all cases), and having high-grade squamous intraepithelial lesions (HSIL) as the precursor lesion; b) the other, HPV independent, related to vulvar dermatosis (lichen sclerosus), and having differentiated vulvar intraepithelial neoplasia (dVIN) as the precursor lesion.2–6 While those two pathways present as concurrent in VSCC carcinogenesis, there are reports of HPV-related cancers in women with LP, probably due to HPV reactivation or predisposition to acquire new HPV infection, which eventually can originate HSIL.4,5
There is an association between LP and cancer in the upper gastrointestinal tract neoplasia (oral cavity, tongue, esophagus).7 However, the risk of VSCC in women with vulvar LP is still controversial. There are studies describing an incidence of VSCC two times higher in women with vulvar LP7,8, while another study focusing on HPV-independent vulvar cancer did not find any evidence of hypertrophic, classic or erosive LP in VSCC specimens.2 Importantly, in one study that associated LP to VSCC, the disease tended to be more aggressive when vulvar LP was present (higher rate of regional lymph node metastases at presentation and a rate of local recurrence of 40%).8
In face of contradictory evidence when revisiting VSCC and LP, our study aimed to analyze a series of women with vulvar LP followed during an 11 years period, to assess the risk of developing preinvasive and invasive vulvar lesions.