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.

The aim of the study was to assess the histology of normal vulvar skin with attention to anatomic location and epithelium type. We performed a retrospective histologic review of 118 vulvar biopsies and excisions obtained between 2010 and 2014 with adjacent normal skin or mucosa. Exclusions included age younger than 18 years, vestibulectomy, labiaplasty, inflammatory dermatoses, and insufficient normal tissue for assessment. Stratum corneum morphology was assessed as basket weave, compact, or intermediate. Stratum granulosum cell layer number and epithelial thickness were recorded. Dermal lymphocytic infiltrate was described as nil, sparse, moderate, or dense. Fischer exact test, Pearson χ, and Student t test were used for statistical analysis. There were 7 cases from mons pubis, 11 from perineum, 83 from labia, and 17 from vestibule. In the skin, the stratum corneum morphology was basket weave in 31%, compact in 35%, and intermediate in 34%. Stratum corneum at the mons pubis was uniformly basket weave, whereas at perineum, it was either compact or intermediate (7/7 vs 0/11; p < .001); the labia demonstrated all 3 morphologies. Parakeratosis (PK) was identified at the specimen edge in 4 cases of hairless skin and 7 cases of squamous mucosa. Mean epithelial thickness and dermal lymphocytic infiltration were similar in specimens with and without PK. Compact stratum corneum of vulvar skin and a zone of PK at the mucocutaneous junction may be normal histological findings. Pathologists need to be aware of site-related differences of the vulvar epithelium to avoid overdiagnosis of pathological conditions.

Objective: Nonsclerotic lichen sclerosus (NSLS) refers to the clinicopathologic situation of examination findings consistent with lichen sclerosus (LS) but without dermal sclerosis on microscopy. This review aims to describe the features of NSLS and provide a classification framework. Methods: The International Society of the Study of Vulvovaginal Diseases tasked the Difficult Pathologic Diagnoses Committee with development of consensus documents for conditions with problematic histopathology. The Difficult Pathologic Diagnoses Committee reviewed the literature on NSLS and formulated descriptions and diagnostic criteria, then approved by the International Society of the Study of Vulvovaginal Diseases membership. Results: Nonsclerotic LS may be categorized into 4 histopathologic subtypes: lichenoid dermatitis, hypertrophic lichenoid dermatitis, dermal fibrosis without acanthosis, and dermal fibrosis with acanthosis. Each has a pathologic differential diagnosis of 1 or more entities, so clinical correlation is required for final diagnosis of LS. There is no evidence to support a reliable association between absent sclerosis and clinical appearance, duration, or oncogenic potential of LS. Conclusions: Pathologists and clinicians should be familiar with the concept of NSLS and its implications for patient management. Use of the term “early LS” to indicate a lack of sclerosis in presumed LS should be abandoned. Clinical correlation is required to confirm LS from among the differential diagnoses.

Objective: The aim of the study was to identify whether erosive lichen sclerosus (LS) is a distinct clinicopathologic subtype. Materials and Methods: The pathology database was searched for “erosion,” “erosive,” “ulcer,” and “lichen sclerosus.” Inclusion criteria were histopathologic diagnosis of LS and erosion or ulcer overlying a band of hyalinization and/or fibrosis. Exclusions were concurrent neoplasia and insufficient tissue. Histopathologic review documented site, epithelial thickness, adjacent epidermal characteristics, infiltrate, and dermal collagen abnormality. Clinical data included demographics, comorbidities, examination findings, microbiologic results, treatment, and response. Results: Ten examples of erosive LS and 15 of ulcerated LS occurred in 24 women with a mean age of 67 years. Ulcerated LS was associated with diabetes and nontreatment at time of biopsy. Clinicians identified red patches in all but 1 case of erosive LS. Ulcerated LS was documented as fissure, ulcer, or white plaque, with 8 (53%) described as lichenified LS with epidermal breaches. Erosive LS favored hairless skin with normal adjacent stratum corneum sloping gently into erosion, whereas most ulcers in LS had an abrupt slope from hair-bearing skin. All cases were treated with topical steroids; 2 patients with erosive LS and 10 with ulcerated LS also had oral antifungals, topical estrogen, antibiotics, and/or lesional excision. Treatment yielded complete resolution in 50%. Conclusions: Erosive LS is an unusual clinicopathologic subtype characterized by red patches on hairless skin seen microscopically as eroded epithelium overlying a band of hyalinized or fibrotic collagen. In contrast, ulcerated LS is usually a traumatic secondary effect in an uncontrolled dermatosis.