The impact of terminology for vulvar intraepithelial lesions has been significant over the years, because it has affected diagnosis, treatment, and research. The introduction of the Lower Anogenital Squamous Terminology (LAST) in 2012 raised 2 concerns in relation to vulvar lesions: firstly, the absence of reference to “differentiated vulvar intraepithelial neoplasia” (differentiated VIN) could lead to its being overlooked by health care providers, despite its malignant potential. Secondly, including the term “low-grade squamous intraepithelial lesion” (LSIL) in LAST recreated the potential for overdiagnosis and overtreatment for benign, self-limiting lesions. The International Society for the Study of Vulvovaginal Disease (ISSVD) assigned the terminology committee the task of developing a terminology to take these issues into consideration. The committee reviewed the development of terminology for vulvar SILs with the previous 2 concerns in mind and reviewed several new terminology options. The final version accepted by the ISSVD contains the following: 1) Low-grade SIL of the vulva or vulvar LSIL, encompassing flat condyloma or human papillomavirus effect. 2) High-grade SIL or vulvar HSIL (which was termed “vulvar intraepithelial neoplasia usual type” in the 2004 ISSVD terminology). 3) Vulvar intraepithelial neoplasia, differentiated type. The advantage of the new terminology is that it includes all types of vulvar SILs, it provides a solution to the concerns in relation to the application of LAST to vulvar lesion, and it is in accordance with the World Health Organization classification as well as the LAST, creating unity among clinicians and pathologists.

Objectives The impact of terminology for vulvar intraepithelial lesions has been significant over the years, because it has affected diagnosis, treatment, and research. The introduction of the Lower Anogenital Squamous Terminology (LAST) in 2012 raised 2 concerns in relation to vulvar lesions: firstly, the absence of reference to “differentiated vulvar intraepithelial neoplasia” (differentiated VIN) could lead to its being overlooked by health care providers, despite its malignant potential. Secondly, including the term “low-grade squamous intraepithelial lesion” (LSIL) in LAST recreated the potential for overdiagnosis and overtreatment for benign, self-limiting lesions. Materials and Methods The International Society for the Study of Vulvovaginal Disease (ISSVD) assigned the terminology committee the task of developing a terminology to take these issues into consideration. The committee reviewed the development of terminology for vulvar SILs with the previous 2 concerns in mind and reviewed several new terminology options. Results The final version accepted by the ISSVD contains the following: •Low-grade SIL of the vulva or vulvar LSIL, encompassing flat condyloma or human papillomavirus effect. •High-grade SIL or vulvar HSIL (which was termed “vulvar intraepithelial neoplasia usual type” in the 2004 ISSVD terminology). •Vulvar intraepithelial neoplasia, differentiated type. Conclusions The advantage of the new terminology is that it includes all types of vulvar SILs, it provides a solution to the concerns in relation to the application of LAST to vulvar lesion, and it is in accordance with the World Health Organization classification as well as the LAST, creating unity among clinicians and pathologists.

The aim of the study was to estimate the neoplastic potential of vulvar lichen sclerosus (VLS). This was a retrospective study of 976 women with VLS. We recorded age at diagnosis of VLS, length of follow-up, and type of neoplasia, categorized as the following: (1) vulvar intraepithelial neoplasia (VIN), further subdivided in differentiated VIN (dVIN) and high-grade squamous intraepithelial lesion; (2) superficially invasive squamous cell carcinoma; and (3) frankly invasive squamous cell carcinoma. Neoplasia incidence risk, neoplasia incidence rate, and cumulative probability of progression to neoplasia according to the Kaplan-Meier method were estimated. Log-rank test was used to compare the progression-free survival curves by age at diagnosis of VLS. The mean age at diagnosis of VLS was 60 (median = 60; range = 8-91) years. The mean length of follow-up was 52 (median = 21; range = 1-331) months. The following 34 patients developed a neoplasia: 8 VIN (4 dVIN, 4 high-grade squamous intraepithelial lesions), 6 keratinizing superficially invasive squamous cell carcinoma (5 with adjacent dVIN), and 20 keratinizing invasive squamous cell carcinoma (1 with adjacent dVIN). The neoplasia incidence risk was 3.5%. The neoplasia incidence rate was 8.1 per 1,000 person-years. The cumulative probability of progression to neoplasia increased from 1.2% at 24 months to 36.8% at 300 months. The median progression-free survival was significantly shorter in older women (≥70 years) when compared with that in younger women (p = .003). Vulvar lichen sclerosus has a nonnegligible risk of neoplastic transformation and requires a careful and lifelong follow-up in all patients, particularly in elderly women. Early clinical and histological detection of preinvasive lesions is essential to reduce the risk of vulvar cancer.

Objective: The aim of the study was to describe the features required for diagnosis of differentiated vulvar intraepithelial neoplasia (dVIN) and vulvar aberrant maturation (VAM). Materials and Methods: The International Society of the Study of Vulvovaginal Diseases tasked the difficult pathologic diagnoses committee to develop consensus recommendations for clinicopathologic diagnosis of vulvar lichen planus, lichen sclerosus, and dVIN. The dVIN subgroup reviewed the literature and formulated diagnostic criteria that were reviewed by the committee and then approved by the International Society of the Study of Vulvovaginal Diseases membership. Results: Differentiated vulvar intraepithelial neoplasia is the immediate precursor of human papillomavirus (HPV)–independent vulvar squamous cell carcinoma and shows a spectrum of clinical and microscopic appearances, some overlapping with HPV-related neoplasia. The histopathologic definition of dVIN is basal atypia combined with negative or nonblock-positive p16 and basal overexpressed, aberrant negative, or wild-type p53. The most common pattern of dVIN is keratinizing with acanthosis, aberrant rete ridge pattern, and premature maturation. The morphologic spectrum of keratinizing dVIN includes hypertrophic, atrophic, acantholytic, and subtle forms. A few dVIN cases are nonkeratinizing, with basaloid cells replacing more than 60% of epithelium. Vulvar aberrant maturation is an umbrella term for lesions with aberrant maturation that arise out of lichenoid dermatitis and lack the basal atypia required for dVIN. Conclusions: Evaluation of women at risk for dVIN and VAM requires a collaborative approach by clinicians and pathologists experienced in vulvar disorders. Close surveillance of women with lichen sclerosus and use of these recommendations may assist in prevention of HPV-independent squamous cell carcinoma through detection and treatment of dVIN and VAM.