Hypertrophic lichen sclerosus sine sclerosis: clues to histopathologic diagnosis when presenting as psoriasiform lichenoid dermatitis

Single-cell and spatial transcriptomics of vulvar lichen sclerosus reveal multi-compartmental alterations in gene expression and signaling cross-talk

Vulvar diseases are a critical yet often neglected area of women's health, profoundly affecting patients' quality of life and frequently resulting in long-term physical and psychological challenges. Lichen sclerosus (LS) is a chronic inflammatory skin disorder that predominantly affects the vulva, leading to severe itching, pain, scarring, and an increased risk of malignancy. Despite its profound impact on affected individuals, the molecular pathogenesis of vulvar LS (VLS) is not well understood, hindering the development of FDA-approved therapies. Here, we utilize single-cell and spatial transcriptomics to analyze lesional and non-lesional skin from VLS patients, as well as healthy control vulvar skin. Our findings demonstrate histologic, cellular, and molecular heterogeneities within VLS, yet highlight unifying molecular changes across keratinocytes, fibroblasts, immune cells, and melanocytes in lesional skin. They reveal cellular stress and damage in fibroblasts and keratinocytes, enhanced T cell activation and cytotoxicity, aberrant cell-cell signaling, and increased activation of the IFN, JAK/STAT, and p53 pathways in specific cell types. Using both monolayer and organotypic culture models, we also demonstrate that knockdown of select genes, which are downregulated in VLS lesional keratinocytes, partially recapitulates VLS-like stress-associated changes. Collectively, these data provide novel insights into the pathogenesis of VLS, identifying potential biomarkers and therapeutic targets for future research.

Nonsclerotic Lichen Sclerosus of Vulva: A Clinicopathologic Analysis

The International Society of the Study of Vulvovaginal Diseases (ISSVD) recently defined nonsclerotic lichen sclerosus (NSLS) as a scenario wherein the clinical findings are consistent with lichen sclerosus (LS), but no microscopic evidence of dermal sclerosis is found and recognized 4 histologic subcategories. Herein, we present an institutional experience with NSLS, with an emphasis on frequency, application of the ISSVD categories in routine practice, and clinicopathologic correlation. The authors reviewed clinical and pathologic findings for consecutive vulvar biopsies in which LS was a clinical and/or pathologic consideration. Cases were classified as classical/sclerotic LS (CLS), NSLS (per ISSVD criteria), and "unclassified," the latter of which were cases not classifiable as NSLS or CLS, despite a clinical impression or LS or LS being a significant clinical consideration (ie, "clinical LS"). In clinical LS cases, CLS and NSLS were diagnosed histologically in 61% (182/298) and 15% (44/298), respectively, whereas the remainder were histologically unclassified. The latter group was microscopically heterogeneous, devoid of a consistent pathologic profile, and generally showed absence, focality, minimality, ambiguity, or infrequency of features that would have allowed their categorization into one of the NSLS categories. Among the 4 categories for the categorizable NSLS cases, the "lichenoid dermatitis" pattern (61.4%) was the commonest, followed by dermal fibrosis with acanthosis (22.7%), dermal fibrosis without acanthosis (9.1%), and hypertrophic lichenoid dermatitis (6.8%). The clinical response rates to topical therapies for the NSLS and unclassified groups were 71% and 62%, respectively (P=0.4). Our findings highlight the significance of clinicopathologic correlation in the diagnosis of NSLS. In the setting of clinical LS, some histologic evidence to support that impression is found in most cases when the ISSVD system for diagnosis and classification of biopsies is applied. However, a subset of clinical LS cases are not pathologically classifiable as either CLS or any of the NSLS categories; these display nonspecific histologic features and require future study.

Nonsclerotic Lichen Sclerosus: Definition of a Concept and Pathologic Description

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.

Idiopathic Lichenoid and Granulomatous Vulvitis: A Distinct Clinicopathological Entity

ABSTRACT

The combination of lichenoid and granulomatous inflammation is uncommon in vulval biopsies. We present a series of 5 patients with lichenoid and granulomatous vulvitis, presenting with clinical changes resembling lichen sclerosus. Despite detailed clinicopathological investigation and follow-up, there was no apparent association with an underlying recognized cause. All 5 cases occurred in postmenopausal women and displayed a distinctive histological pattern of superficial band-like inflammation with granulomas "anchored" to the dermoepidermal junction. There was no evidence of deeper granulomatous inflammation. Despite repeated biopsies over 2 years in 2 patients, neither developed typical histological features of lichen sclerosus. We postulate that idiopathic lichenoid and granulomatous vulvitis may represent a distinct clinicopathologically defined vulvar dermatosis.

Vulvar dermatoses-Can a pattern-based approach improve diagnostic yield?

BACKGROUND

Vulvar dermatoses (VD) pose a formidable challenge to clinicians and pathologists owing to various factors. The factors included are the histopathological heterogeneity of the vulva, moist and frictional environment, and the limited experience of gynecologists and general histopathologists in this field. To address this issue, the International Society for the Study of Vulvovaginal Disease (ISSVD) proposed a histopathological tissue reaction-based classification system for VD. Therefore, we attempted to study the utility of the 2006 ISSVD classification in reporting VD. We further evaluated if a dermatopathologist review could improve the diagnostic yield.

MATERIALS AND METHODS

The vulvar biopsy reports (N = 106) were retrieved from histopathology case files, out of which benign non-infectious conditions (n = 55) were included in the study. The diagnosis retrieved from the case files was considered the initial diagnosis. Three dermatopathologists reviewed each biopsy, and a tissue reaction pattern/diagnosis was assigned as per ISSVD 2006, and this was considered a review diagnosis. The initial and review diagnoses were compared and analyzed. We further studied and analyzed the effect of the dermatopathologist's review on the diagnostic yield.

RESULTS

The sclerotic pattern (34.6%) was the commonest tissue reaction pattern, followed by spongiotic (18%) and acanthotic patterns (14.5%) independently or in combination. The non-specific/descriptive report rate was significantly decreased following 2006 ISSVD and the dermatopathologist's review (83.6% vs.1.8%).

CONCLUSION

Rendering tissue reaction patterns to vulvar biopsies will enable a comprehensive understanding of lesions and aid in clinically relevant reporting. In addition, dermatopathologists' review of difficult vulvar biopsies increases the diagnostic yield.

HPV-independent, p53-wild-type vulvar intraepithelial neoplasia: a review of nomenclature and the journey to characterize verruciform and acanthotic precursor lesions of the vulva

Vulvar squamous cell carcinomas and their precursors are currently classified by the World Health Organization based on their association with high-risk human papillomavirus (HPV). HPV independent lesions often harbor driver alterations in TP53, usually seen in the setting of chronic vulvar inflammation. However, a group of pre-invasive vulvar squamous lesions is independent from both HPV and mutant TP53. The lesions described within this category feature marked acanthosis, verruciform growth and altered squamous maturation, and over the last two decades several studies have added to their characterization. They have a documented association with verrucous carcinoma and conventional squamous cell carcinoma of the vulva, suggesting a precursor role. They also harbor recurrent genomic alterations in several oncogenes, mainly PIK3CA and HRAS, indicating a neoplastic nature. In this review, we provide a historical perspective and a comprehensive description of these lesions. We also offer an appraisal of the terminology used over the years, going from Vulvar Acanthosis with Altered Differentiation and Verruciform Lichen Simplex Chronicus to Differentiated Exophytic Vulvar Intraepithelial Lesion and Vulvar Aberrant Maturation, the latter term having been recently proposed by the International Society for the Study of Vulvovaginal Diseases. In line with the recognition of these lesions by the 2020 World Health Organization Classification of Tumours as a neoplastic precursor, we herein propose the term HPV-independent, p53-wild-type verruciform acanthotic Vulvar Intraepithelial Neoplasia (HPVi(p53wt) vaVIN), which better conveys not only the pathology but also the neoplastic nature and the biologic risk inherent to these uncommon and challenging lesions. We outline strict morphologic and immunohistochemical criteria for its diagnosis and distinction from mimickers. Immunohistochemistry for p16 and p53 should be performed routinely in the diagnostic work-up of these lesions, and the morphologic alternative term vaVIN should be reserved for instances in which p16/HPV/p53 status is unknown. We also discuss management considerations and the need to further explore precursors within and beyond the spectrum of verruciform acanthotic vulvar intraepithelial neoplasia.

Lymphocyte-Peppered Sclerotic Collagen: An Additional Histological Clue in Lichen Sclerosus, Morphea, and Systemic Sclerosis

BACKGROUND

"Line sign," "cookie cutter sign," "square biopsy sign," "high eccrine glands sign" have been previously described in morphoea and lichen sclerosus. We found focal areas of thickened collagen bundles with lymphocytes interspersed between them in several biopsies of these conditions.

MATERIALS AND METHODS

We reviewed slides of sclerosing disorders obtained from the archives of the pathology department in our hospital for the period 2013-2019.

RESULTS

A total of 73 slides including 40 of lichen sclerosus, 24 of morphea, 2 of lichen sclerosus-morphea overlap, and 7 of systemic sclerosis were evaluated. Lymphocytes were noted between sclerotic collagen bundles in 46 (63%) slides, being most common in lichen sclerosus (80%, 32/40) followed by morphea (50%, 12/24), whereas it was seen in one case each of lichen sclerosus with morphea overlap (50%, 1/2) and systemic sclerosis (14.3%, 1/7). The finding was noted in the upper dermis in 20 of 32 (62.5%) slides of lichen sclerosus and in both the superficial and deep dermis in 11 (91.7%) of 12 slides of morphea.

CONCLUSION

Lymphocyte-peppered sclerotic collagen may be a useful histological clue to the diagnosis of lichen sclerosus, morphea, and systemic sclerosis.

Clinicopathologic Diagnostic Criteria for Vulvar Lichen Planus

OBJECTIVE

The aim of the study was to describe the clinical and histopathologic features required for a clinicopathologic diagnosis of vulvar lichen planus (LP), which is divided into 3 types: erosive, classic, and hypertrophic.

MATERIALS AND METHODS

The International Society of the Study of Vulvovaginal Diseases tasked the Difficult Pathologic Diagnoses committee with development of a consensus document for the clinicopathologic diagnosis of vulvar LP, lichen sclerosus, and differentiated vulvar intraepithelial neoplasia. The LP subgroup reviewed the literature and formulated diagnostic criteria, then approved by the International Society of the Study of Vulvovaginal Diseases membership.

RESULTS

The clinicopathologic diagnosis of erosive LP incorporates 5 criteria: (a) a well-demarcated, glazed red macule or patch at labia minora, vestibule, and/or vagina, (b) disease affects hairless skin, mucocutaneous junction, and/or nonkeratinized squamous epithelium, (c) evidence of basal layer damage, categorized as degenerative or regenerative, (d) a closely applied band-like lymphocytic infiltrate, and (e) absent subepithelial sclerosis. The clinicopathologic diagnoses of classic and hypertrophic LP each require a characteristic clinical appearance accompanied by hyperkeratosis, hypergranulosis, acanthosis, basal layer degeneration, a closely applied lymphocytic infiltrate, and absent dermal sclerosis, with hypertrophic LP showing marked epithelial abnormality compared with classic LP.

CONCLUSIONS

Clinicopathological correlation yields the most reliable diagnosis of vulvar LP. Disease appearance overlaps with other physiologic, dermatologic, infectious, and neoplastic entities; a low threshold for biopsy at all morphologically distinct areas is recommended. Use of the histopathologic criteria described in this document may reduce the nondiagnostic biopsy rate for clinically diagnosed LP.

Diagnostic Criteria for Differentiated Vulvar Intraepithelial Neoplasia and Vulvar Aberrant Maturation

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.

Thickening of the basement membrane as a diagnostic sign of mycosis fungoides

The epidermal basement membrane (BM) is readily identified on skin biopsy specimens stained with periodic acid-Schiff (PAS) and PAS with diastase (PAS-D). Thickening of BM can be evidenced in several inflammatory and tumoral conditions. We noticed that most of our biopsy specimens of mycosis fungoides (MF) showed thickening of the BM. We decided to retrospectively study BM thickness in 27 biopsy specimens of MF and compare them with 27 cutaneous biopsy specimens of inflammatory diseases. We studied PAS and PAS-D stains in all cases and we measured BM thickness with an ocular micrometer. Cases were scored in a four-tiered system: 0: no detectable staining; 1+ (mild: < 5 μm); 2+ (moderate: 5-9 μm); and 3+ (prominent: >9 μm). The difference between both groups (MF vs controls) was highly significant for BM thickness values by both one- and two-tailed t tests (P < 0.0006). While only 3 biopsy specimens from the controls (11.11%) showed areas of 3+ thickening, 12 biopsy specimens of MF (44.44%) showed areas of 3+ thickening, and most cases showed diffuse, at least 2+ thickening, while the controls showed more segmental, mostly 1 or 2+ staining. We conclude that thickening of BM can be useful in the differential diagnosis with inflammatory conditions.

Structured analysis of histopathological characteristics of vulvar lichen sclerosus in a juvenile population

Genital lichen sclerosus (LS), a chronic noninfectious dermatosis, is not rare in pediatric dermatology. The histopathological diagnosis in children and adults in both genital and nongenital LS is considered to be the same and encompasses a broad range of possible characteristics. Clinical manifestations and treatment options of genital LS in children are different depending on gender. The vast majority of boys are treated with circumcision, making for a larger amount of information on the histopathology of genital LS in boys, whereas substantial information on the histopathology of juvenile vulvar LS is lacking. In girls, vulvar LS almost always persists beyond puberty and, therefore, presents a particular challenge to clinicians and cause for concern for the patient. Vulvar LS in childhood and adolescence (juveniles) is underreported, and there are uncertainties with regard to the long-term course of the disease when it occurs at an age when the vulva is still developing. The present study investigates biopsies of 100 juvenile cases of vulvar LS and analyzes the presence or absence of the most salient histopathological characteristics of LS that are described in the literature. We found that the range of histopathological characteristics known for adult LS are also present in juvenile vulvar LS, even at very young ages, including histopathological features associated with autoimmune disease, in support of the idea of a similar pathogenesis.

Lichenoid dermatoses involving the vulva: A clinical-pathologic correlation✰

The lichenoid tissue reaction pattern generally signifies cytotoxic damage to the epithelium. When such reaction pattern occurs on vulvar skin or mucosa, the effects can result in considerable morbidity. None of the entities discussed in this review are entirely unique to the vulva, however, some entities may classically occur at this site, while others tend to be widespread diseases that may incidentally affect vulvar skin and mucosa. Given the complex anatomy of the vulva and the bridging of a site showing both keratinizing squamous epithelium and non-keratinizing squamous mucosa, histopathologic features may display variation in presentation. Although identification of a "lichenoid reaction pattern" alone may provide insight into the disease process, understanding of clinical presentation and specific sites of involvement, along with recognition of the nuanced features of the disease entities can help establish a specific diagnosis. Accurate histopathologic diagnoses by pathologists can improve the ability for treating clinicians to implement timely and effective treatment.

Elastophagocytosis and interstitial granulomatous infiltrate are more common in extragenital vs genital lichen sclerosus

BACKGROUND

Genital and extragenital lichen sclerosus (LS) share similar histopathologic features. A recent small series documented elastophagocytosis uniquely in extragenital LS. We evaluated a larger series of LS for elastophagocytosis, elastic fiber loss, and other histopathologic features. We evaluated matrix metalloproteinase (MMP) expression to determine if these proteins play an etiologic role.

METHODS

Genital (n = 42) and extragenital (n = 41) LS biopsies were examined for histopathologic features, elastic fiber alteration (Verhoeff van Gieson staining), and MMP-2 and MMP-9 expression (immunohistochemistry).

RESULTS

Elastophagocytosis and an interstitial granulomatous pattern were significantly more common in extragenital LS than genital LS (43.9% vs 4.7% and 56.1% vs 9.5%). Extragenital LS had mild/focal elastic fiber loss (43.9%), while genital LS had moderate (61.9%) or marked (19%) loss. MMP-9 was diffusely expressed in histiocytes in both types of LS (genital 97.5%; extragenital 100%). Weak MMP-2 expression was seen in genital (58%) and extragenital (55%) LS.

CONCLUSIONS

Extragenital LS, but not genital LS, frequently exhibits elastophagocytosis and interstitial granulomatous infiltrate, and these patterns could contribute to elastic fiber destruction in extragenital LS. While MMP-2 and MMP-9 expression are common in LS, expression did not significantly differ depending on anatomic site and thus is unlikely to explain observed histopathologic differences.

Classic and Hypertrophic Vulvar Lichen Planus

OBJECTIVES

Three types of lichen planus (LP) occur on the vulva: erosive, classic, and hypertrophic. The latter 2 occur on keratinized skin and little is known about their clinicopathologic appearance.

MATERIALS AND METHODS

Vulvar biopsies of keratinized skin reported as LP or "lichenoid" between 2011 and 2017 were reviewed. Inclusion required age of older than 18 years, a lichenoid tissue reaction, and insufficient abnormal dermal collagen to diagnose lichen sclerosus. Clinical and histopathologic data were collected and cases were categorized as hypertrophic, classic, or nonspecific lichenoid dermatosis. Descriptive statistics were performed and groups were compared with the Fisher exact test.

RESULTS

Sixty-three cases met criteria for inclusion. Twenty-nine (46%) cases were categorized as hypertrophic LP, 21 (33%) as classic LP, and 13 (21%) as nonspecific lichenoid dermatosis. There were no significant differences in age, primary symptom, biopsy location, or duration of disease between the 3 groups. When compared with classic and nonspecific disease, hypertrophic LP was less likely to have comorbid dermatoses and more likely to be red, diffuse, have scale crust, and contain plasma cells in the infiltrate. Nonspecific disease had similar clinical features to classic LP but was less likely than the other 2 categories to have a dense lymphocytic infiltrate and exocytosis.

CONCLUSIONS

Vulvar LP on keratinized skin has a diversity of appearances and presents a clinicopathologic challenge. Further research is required to understand the natural history of hypertrophic LP and the underlying diagnosis of nonspecific lichenoid cases.

Is Vulvovaginal Lichen Planus Associated With Squamous Cell Carcinoma?

Objective

The aim of the study was to assess for the presence of vulvar lichen planus (LP) in association with human papillomavirus (HPV)–independent squamous cell carcinoma (SCC).

Materials and Methods

We performed a clinicohistopathologic review of consecutive vulvectomies and wide local excisions for HPV-independent vulvar or vaginal SCC from 2007 to 2017. Data collected included site of SCC, adjacent precursor lesions and dermatoses, dermatologic treatment, and outcome.

Results

There were 43 cases of primary HPV-independent vulvar SCC treated by excision, but no vaginal cancers. Eighteen women (42%) had a preoperative diagnosis of lichen sclerosus (LS); none had a diagnosis of LP. Topical corticosteroids were prescribed in 19 (44%) of 43, with 4 women placed on maintenance therapy. Tumors arose from the labia minora, labia majora, and periclitoris, but not from vestibule or perianus. On histopathological review, LS was present in 41 (95%) of 43 specimens, 1 had a nonspecific lichenoid reaction, and 1 had lichen simplex; both of the latter had subsequent biopsies showing LS. Lichen planus was not seen in association with SCC. Differentiated vulvar intraepithelial neoplasia (dVIN) was present in 38 (88%) of 43 specimens, whereas 1 had acanthosis with altered differentiation and 4 (9%) had no precursor lesion. Differentiated vulvar intraepithelial neoplasia had standard, basaloid, and hypertrophic morphology, superficially resembling erosive LP in 9 (24%) of 38 and hypertrophic LP in 6 (16%) of 38.

Conclusions

Lichen planus was not seen in association with HPV-independent vulvar SCC, whereas LS was underrecognized and inadequately treated in this group. Pathologists should be aware that dVIN may superficially resemble erosive or hypertrophic LP.

Lichenoid Dermatitis of the Vulva: Diagnosis and Differential Diagnosis for the Gynecologic Pathologist

Inflammatory processes affecting the vulva may present a unique challenge due to location specific changes. Different factors are behind the intricacy in the presentation of vulvar dermatoses. First, the vulva is lined by different epithelia (hair-bearing keratinized epithelium, modified mucosa, and mucosa). Furthermore, among other factors, this organ is exposed to friction, occlusion, and trauma. Lastly, as there is a tendency to look for health care advice at an advanced stage of the disease, the lesion may be modified by secondary changes due to self-treatment. This article describes the clinical presentation and pathologic features of vulvar dermatoses with a lichenoid pattern and highlights practical points for their diagnoses.

High-Yield Vulvar Histopathology for the Clinician

Certain adjustable factors may influence how helpful a pathology report is to the clinician. Different biopsy techniques may be preferable based on the type of lesion being biopsied and the background epithelial surface. Key observations from the history and physical examination, possibly with a clinical photograph, are helpful to the pathologist. When reading the pathology report, realize the difficulties arising from definitively classifying some diseases and how treatment can affect the tissue. Finally, avoid miscommunication with the pathologist by understanding current nomenclature of vulvar disease.