Evaluation of linear dermatoses by reflectance confocal microscopy in children.

Lichen striatus (LS), linear psoriasis (LPs), linear cutaneous lupus erythematosus (LCLE) and linear lichen planus (LLP) often have similar clinical manifestations, which makes clinical diagnosis with the naked eye difficult; therefore, they are easily misdiagnosed. The purpose of this study was to determine whether reflectance confocal microscopy (RCM) is helpful in differentiating between these four linear dermatoses in children. This retrospective study included 14 patients with LS, nine with LPs, eight with LCLE and 12 with LLP. All patients were analysed using RCM, and biopsies were collected from lesions previously imaged by RCM. For LS, the dermal papillary rings were partially absent, but when present, manifested with small, homogeneously round, bright cells and occasionally highly refractive plump cellular structures, aggregated in clusters. LPs exhibited dark cyst-like structures with small, bright, round cells aggregated at the epidermal level; at the dermal-epidermal junction, homogeneously distributed, enlarged, faint dermal papillary rings and numerous enlarged low-refractive canalicular structures were observed in the superficial dermis. LCLE and LLP exhibited similar manifestations, including epidermal disarray, almost total absence of dermal papillary rings, and various sized refractive structures densely distributed in the dermis. The key distinguishing features of LCLE were the different sized structures mainly clustered around hair follicles, while LLP demonstrated dense structures with a scattered distribution. RCM may be used to distinguish between the key features of LS, LPs, LCLE and LLP in children.

Vulvar Lichenoid Dermatoses With Emphasis on the Distinction Between Lichen Sclerosus and Lichen Planus: A 10-Year Study.

OBJECTIVES: Lichen planus (LP) and lichen sclerosus (LS) are the most common vulvar lichenoid dermatoses. The diagnostic challenges are due to site-specific variation in microscopic appearance and small-sized biopsies. Authentication of diagnostic criteria to distinguish LS and LP to uncover any resemblance or divergence in presentation of these conditions is attempted. METHODS: Cases of vulvar LP and LS diagnosed between January 2012 to December 2022 were included. The clinical details included age, presenting symptoms, examination findings, and other organ involvement. Histopathological analysis of epidermal, dermal, and adnexal findings was done. RESULTS: There were 28 cases of vulvar LP and 72 cases of LS, with a median age of 51 and 60 years, respectively. Depigmentation and atrophy were the major clinical features in LS, whereas ulcers/erosions and erythema were more prevalent in LP with a significantly higher incidence of oral involvement. The most diagnostic feature in LS was diffuse dermal sclerosis (76.8%) and interstitial pattern of inflammation (81.4%), whereas the characteristic features in LP cases was a lichenoid pattern of inflammation (85.7%), necrotic keratinocytes, and lymphocytic exocytosis. In 44.4% of LS, unconventional features like compact orthokeratosis, parakeratosis, thickened/wedge-shaped hypergranulosis, and sawtooth rete pegs were noted. Lichen sclerosus with lichenoid inflammation (21.4%) mimicked LP, from which it was distinguished by presence of thickened or diminished granular layer with basal melanin absence (60%) and dermal homogenization (80%). CONCLUSION: Although the classical, well-established variant of LS poses no diagnostic difficulty, the unconventional variant may mimic LP. Identification of the subtle histological clues demonstrated in this study can help to arrive at the correct diagnosis.

Squamous Cell Carcinoma Arising in Chronic Inflammatory Dermatoses.

Squamous cell carcinoma (SCC) is a known sequela of chronic inflammatory conditions of the skin. Labial discoid lupus erythema-tosus (DLE), oral lichen planus (OLP), and lichen sclerosus have a relatively short lag time from dermatosis onset to manifestation of malignancy; cutaneous DLE, hypertrophic lichen planus, chronic wounds, hidradenitis suppurativa (HS), and necrobiosis lipoidica can be present for decades before an associated malignancy is observed. Vigilant monitoring is essential for orolabial DLE, chronic HS, and chronic wounds because malignancies in these settings are particularly aggressive and often fatal. We summarize what is known about the nature and demographics of SCC arising within chronic inflammatory dermatoses, emphasizing lag time from dermatosis diagnosis to malignancy onset of common inflammatory conditions.

[Study of the kinetics of accumulation and distribution of the photosensitizer photoditazin in the oral mucosa in patients with lichen planus]. / Izuchenie kinetiki nakopleniya i raspredeleniya fotosensibilizatora fotoditazin v slizistoi obolochke rta u patsientov s krasnym ploskim lishaem.

THE AIM OF THE STUDY: Was to explore the accumulation and distribution of the photosensitizer Photoditazine in the oral mucosa when applied to pathological lesions in patients with severe forms of lichen planus. MATERIAL AND METHODS: A clinical and laboratory examination was carried out in 50 patients with severe forms of lichen planus (bullous and erosive-ulcerative) aged 18 to 70 years, including 6 men and 44 women. For autofluorescent imaging a LED device with a wavelength in the violet region of the spectrum (400±10 nm) was used. Quantitative registration of the kinetics of accumulation and distribution of the photosensitizer was carried out using the method of local fluorescence spectroscopy by measuring the fluorescence spectra. RESULTS: The measurements were made before applying the photosensitizer, 10, 20 and 30 minutes after application. The study showed that in most patients with erosive-ulcerative and bullous forms of lichen planus, the accumulation of the photosensitizer in the lesions on the oral mucosa increased as the exposure time increased from 20 to 30 minutes. The fastest accumulation of the photosensitizer occurred in the areas of mucosal lesions with the most pronounced vascularization, namely, in the area of the tongue and the bottom of the oral cavity. CONCLUSION: Using the method of local fluorescence spectroscopy, the kinetics of accumulation and destruction of photosensitizer in pathological areas of the oral mucosa was determined, and therefore the optimal time of laser exposure to the lesion was determined.

TAZ acting as a potential pathogenic biomarker to promote the development of lichen planus.

BACKGROUND: Lichen planus is a chronic inflammatory disorder. Transcriptional coactivator with PDZ-binding motif (TAZ/WWTR1) is an important downstream effector of the Hippo pathway which regulates organ size and tissue homeostasis. But little is known about the role of TAZ in lichen planus so far. OBJECTIVE: To explore the expression of TAZ in lichen planus and normal skin, and to discover the relationship between TAZ expression and the clinical characteristics of lichen planus patients. METHODS: The method of immunohistochemistry was performed to quantify the expression of TAZ in 262 patients with lichen planus and 90 control tissues. Western blot and quantitative real-time reverse transcriptase-PCR (qRT-PCR) analysis were performed to examine and compare TAZ expression in 4 cases of fresh lichen planus lesions and normal skin tissues. RESULTS: TAZ was weakly expressed in the basal layers of the epidermis in normal skin tissues with a positive rate of 52.22% (47/90). But in lichen planus, TAZ was strongly expressed in almost the entire epidermis with a positive rate of 81.30% (213/262), and the difference between the two groups was statistically significant (p<0.05). Additionally, TAZ expression was significantly related to the location of the lichen planus, clinical phenotype, smoking, and alcohol preference (p<0.05). Western blot and qRT-PCR showed that the expression of TAZ in protein and mRNA levels in four cases of lichen planus lesions was significantly higher than that in normal skin tissues. CONCLUSION: TAZ may play a regulatory role in the occurrence and development of lichen planus, which might provide a new perspective for studying pathogenesis and theoretical treatment targets.

Chronic diffuse alopecia in women: a retrospective review of histopathologic diagnoses.

INTRODUCTION: The diseases causing chronic diffuse alopecia and having similar clinical findings, namely chronic telogen effluvium, androgenetic alopecia, and the alopecia with overlapping features, should be differentiated. Recently, diffuse variants of lichen planopilaris have been described with histopathologic features of lichen planopilaris but clinically presenting with diffuse hair loss mostly in an androgenetic pattern. OBJECTIVES: To determine the accurate diagnosis underlying chronic diffuse alopecia in women by evaluating histopathologic findings. PATIENTS AND METHODS: The study included 32 patients with diffuse and clinically noncicatricial alopecia for at least 6 months with no identifiable etiologic factor after general medical history, review of organ systems, and appropriate laboratory tests. Two 4 mm punch biopsies, one from vertex and the other from mid-occiput, were obtained and sectioned transversely. RESULTS: The median age was 30.5 years (range: 22-40 years), and the median duration of hair loss was 4 years (range: 1.5-10 years). The histopathologic diagnosis was androgenetic alopecia, chronic telogen effluvium, and overlapping alopecia in 13 (40.6%), three (9.4%), and four (12.5%) patients, respectively. In the remaining 12 (32.5%) patients, a lichenoid inflammatory reaction affecting the infundibulum and isthmus was noted, and the probable diagnosis of diffuse variant of lichen planopilaris was made. LIMITATIONS: The retrospective nature and the small sample size. CONCLUSION: When the clinical diagnosis is not straightforward and no etiologic factor is found, histopathologic examination is mandatory for the accurate diagnosis of the disorder leading to chronic diffuse alopecia in women.

Acquired dermal macular hyperpigmentation: an overview of the recent updates.

Acquired dermal macular hyperpigmentation (ADMH), previously known as macular pigmentation of uncertain etiology (MPUE), is an umbrella concept that unifies the distinct but overlapping acquired dermal pigmentary disorders like lichen planus pigmentosus, ashy dermatosis, erythema dyschromicum perstans, Riehl's melanosis and pigmented contact dermatitis. All of these disorders usually lack a clinically apparent inflammatory phase, are characterised by dermal pigmentation clinically and histologically, and have a variable protracted disease course. Recently, a proposal has been made to classify these disorders into those with and without contact sensitisation. Dermoscopy is essentially similar across the spectrum of these disorders, and is useful for diagnosis and therapeutic response monitoring. Scoring system has been validated for the same. The treatment of ADMH remains challenging, with multiple topicals, oral therapies including mycophenolate mofetil, and lasers tried. Need of the hour is randomised controlled trials to enhance the therapeutic armamentarium.

Bridging the gaps: management of lichen planus subtypes in a joint dermatology-oral surgery clinic.

Lichen planus (LP) presents with a range of clinical subtypes. It can affect the outer skin, involve the nails and present with alopecia and mucosal symptoms to varying degrees. LP of the outer skin mostly shows a self-limiting course; however, this is not the case for lichen planopilaris and the mucosa-affecting subtypes. The pathogenesis of LP is still incompletely understood. As a result, an effective, targeted therapy is currently lacking and different immunomodulatory approaches are being used in clinical practice. The management of patients with severe oral LP mucosae can be particularly challenging. Although the true risk remains controversial, oral LP is considered a risk factor for the development of squamous cell carcinoma and there is a need for regular screening. The quality of life in patients with LP is significantly impaired because of frequent clinical visits, pain, soreness, inability to eat certain foods, side effects to medication, frustrating therapy attempts and worry regarding cancer risk. We highlight here the advantages of an interdisciplinary dermatology and oral surgery clinic, which can address the domains of tooth status, nutrition, pain and malignant transformation and optimized patient management.

Patterns of Mucin Deposition in Lichen Planopilaris: A Journey From Follicular "Bubbles" to Perifollicular Fibroplasia.

ABSTRACT: Lichen Planopiolaris (LPP) is a scarring alopecia characterised by a perifollicular lymphoid cell infiltrate at the level of the infundibulum and isthmus. While perifollicular mucinous fibroplasia is an established finding in LPP, intrafollicular mucin deposition has not been previously reported. We describe two cases with this histopathology and suggest it may represent a helpful clue to the diagnosis of LPP, in the appropriate clinical setting.

Introducing a novel histopathological scoring system to assess disease activity and chronicity in cutaneous lichen planus: A proposal.

BACKGROUND: Lichen planus (LP) is a chronic inflammatory disorder caused by an autoimmune attack by cytotoxic T-cells. The clinical course is variable, with episodes of remission and exacerbation. A clinicopathological scoring system for cutaneous LP is not available for effectively assessing disease severity and monitoring treatment response. This study was designed with the aim of proposing an objective and reproducible scoring system, comprising histopathological features of active and chronic disease, and to correlate these scores with clinical morphology groups. METHODOLOGY: This is a retrospective study of 200 cases of cutaneous LP, which were categorized into five clinical groups (I-V) at the time of biopsy. The corresponding histopathological feature was assigned a score based on feature of active and chronic disease. Individual scores were summated to calculate a histopathological index (index [AI] and chronicity index [CI]). The comparison of indices between various clinical groups was performed by Mann-Whitney U test. RESULTS: The median AI was lowest (1) for post-inflammatory hyperpigmentation (clinical group I) and highest (7) for the bullous group (clinical group IV). The median CI (7) was highest for the scarring group (clinical group V). The difference between median AI of clinical group I (post-inflammatory hyperpigmentation) and rest of the groups (clinical groups II, III, IV, and V) was statistically significant (p value <0.05). CONCLUSION: We present this clinico-histopathological scoring system as a reliable and facile method of assessing the activity and severity of LP.

ADVERSE DRUG EVENTS: LICHEN PLANUS OF THE PENIS AFTER INTAKE OF NEBIVOLOL- FIRST REPORTED CASE IN THE WORLD LITERATURE.

The pathogenesis of lichen planus and lichenoid-type reactions remains shrouded in mystery to this day, precisely because of the inability to perform acute/specific tests for reproduction of a particular type of reaction (in this case lichenoid) in order to prove a causal relationship. Nevertheless, the concept of molecular mimicry/antigen mimicry as a possible important pathogenetic inducer for lichen planus and lichenoid-type reactions, is increasingly becoming a topic of discussion and remains more than relevant at present. Disturbances in the integrity of tissue homeostasis- in one form or another, in fact, become a powerful generator of cross-mediated immunity, possibly directed at tissue-localized structures/structural elements/proteins or amino acids. The observation and reporting of this kind of disorders (even in the absence of the mentioned tests), as well as their parallel manifestation with a disease such as lichen planus (or lichenoid-type reaction), has led over the years to the validation of the now universal belief that the disease is multifactorially determined. And the causes of disruption of this integrity can be both external- infectious, meicamentous as well as internal- tumoral, paraneoplastic, etc. Medication induction or triggering of lichen planus by beta blockers has been observed and reported frequently over the years, and the clinical picture can vary and be extremely heterogeneous. We describe the first case in the world literature of a lichen planus after nebivolol administration that developed in the strictly restricted area of the glans penis. According to a reference in the medical literature, this is also the second case in the world literature of penile localized lichen planus after beta blocker intake. The other analogous one was recorded and described back in 1991 after propranolol intake.

Differential proteomic expression profiles in vulvar lichen planus as compared to normal vulvar tissue, vulvar lichen sclerosus, or oral lichen planus: An exploratory study.

Vulvar lichen planus (VLP) is a chronic inflammatory disease which adversely affects patients' quality of life. The pathogenesis of VLP is unknown although Th1 immune response has been implicated. We aimed to discover specific tissue-based protein biomarkers in VLP compared to normal vulvar tissue (NVT), vulvar lichen sclerosus (VLS) and oral lichen planus (OLP). We used laser capture microdissection-liquid chromatography- tandem mass spectrometry to assess protein expression in fixed lesional mucosal specimens from patients with VLP (n = 5). We then compared proteomic profiles against those of NVT (n = 4), VLS (n = 5), OLP (n = 6) and normal oral mucosa (n = 5), previously published by our group. IL16, PTPRC, PTPRCAP, TAP1 and ITGB2 and were significantly overexpressed in VLP compared to NVT. Ingenuity pathway analysis identified antigen presentation and integrin signalling pathways. Proteins overexpressed in both VLP versus NVT and OLP versus NOM included IL16, PTPRC, PTPRCAP, TAP1, HLA-DPB1, HLA-B and HLA-DRA. This proteomic analysis revealed several overexpressed proteins in VLP that relate to Th1 autoimmunity, including IL16. Overlapping pathways, including those involving IFNγ and Th1 signalling, were observed between VLP, VLS, and OLP.

Hyperpigmented Mycosis Fungoides Masquerading as Longstanding Lichen Planus Pigmentosus: A Diagnostic Pitfall.

BACKGROUND: Mycosis fungoides (MF) is a rare primary cutaneous T-cell lymphoma, accounting for 50%-60% of all cutaneous T-cell lymphoma cases. It has a prevalence of approximately 5-6 cases per 1 million people annually and a higher incidence in dark-skinned populations. CASE PRESENTATION: We report a case of hyperpigmented MF in a 72-year-old dark-skinned man with a 5-year history of progressive, widespread poikilodermatous patches and thin plaques on the back and bilateral legs. The patient had been treated for lichen planus pigmentosus for 5 years without significant response to therapy. ASSESSMENT: Multiple biopsies revealed a band-like lymphoid infiltrate in the dermis, accompanied by intraepidermal lymphocytes, some of which had larger hyperchromatic nuclei. CD4 + T lymphocytes were predominant over CD8 + T-positive cells located along the epidermis, dermoepidermal junction, and in the dermis. DIAGNOSIS: A diagnosis of hyperpigmented MF was made based on the clinical, histopathological, and immunohistochemical findings. CONCLUSION: This case report highlights the importance of considering hyperpigmented MF as a differential diagnosis in patients with longstanding lichen planus pigmentosus, particularly when there is a lack of response to therapy.

Histopathologic Spectrum of Alopecias Seen in a Jamaican Setting.

ABSTRACT: Alopecia is common in Jamaican, primarily Afro-Caribbean patients. We performed a retrospective review examining the histopathologic alopecia diagnoses over ∼5 years. Requisition forms and pathology reports were assessed. Demographic/clinical/technical/diagnostic and pathologic findings of chronicity/severity data were recorded. Three hundred thirty-eight biopsies were included. The majority were 4 mm punches, grossed horizontally. The F:M ratio was 4.8:1, mean age = 42.7 years, and mean duration of alopecia = 5.1 years. Cicatricial alopecias (CAs) predominated over non-CAs (NCAs). The top 10 diagnoses were central centrifugal CA (21.9%), folliculitis decalvans (10.9%), multifactorial alopecias (10.1%), pattern hair loss (8%), lichen planopilaris (7.1%), alopecia areata (6.2%), discoid lupus erythematosus (6.2%), nonclassifiable lymphocytic scarring alopecias (5.6%), frontal fibrosing alopecia (5.3%), and nonspecific NCAs (5%). This contrasted with other richly pigmented populations where discoid lupus erythematosus predominates. Other interesting findings included relatively frequent folliculitis decalvans and lichen planus pigmentosus in 40.9% of frontal fibrosing alopecia cases. Scarring/nonscarring clinicopathologic congruence occurred in 83.4%.Regarding histopathologic features of severity/chronicity, CAs had markedly decreased hair counts. Perifollicular fibrosis affecting retained hairs occurred in 75% of CAs, moderate to severe in >50% of these. Approximately 50% of NCA samples demonstrated advanced miniaturization (T:V ratio <2:1). In our study, relatively young women with chronic hair loss and CA are most frequently biopsied. Central centrifugal CA is the most common diagnosis. Local features of chronic/severe disease are seen microscopically. Clinical impression of scarring/nonscarring correlates well with histopathology.

PD-1 maintains CD8 T cell tolerance towards cutaneous neoantigens.

The peripheral T cell repertoire of healthy individuals contains self-reactive T cells1,2. Checkpoint receptors such as PD-1 are thought to enable the induction of peripheral tolerance by deletion or anergy of self-reactive CD8 T cells3-10. However, this model is challenged by the high frequency of immune-related adverse events in patients with cancer who have been treated with checkpoint inhibitors11. Here we developed a mouse model in which skin-specific expression of T cell antigens in the epidermis caused local infiltration of antigen-specific CD8 T cells with an effector gene-expression profile. In this setting, PD-1 enabled the maintenance of skin tolerance by preventing tissue-infiltrating antigen-specific effector CD8 T cells from (1) acquiring a fully functional, pathogenic differentiation state, (2) secreting significant amounts of effector molecules, and (3) gaining access to epidermal antigen-expressing cells. In the absence of PD-1, epidermal antigen-expressing cells were eliminated by antigen-specific CD8 T cells, resulting in local pathology. Transcriptomic analysis of skin biopsies from two patients with cutaneous lichenoid immune-related adverse events showed the presence of clonally expanded effector CD8 T cells in both lesional and non-lesional skin. Thus, our data support a model of peripheral T cell tolerance in which PD-1 allows antigen-specific effector CD8 T cells to co-exist with antigen-expressing cells in tissues without immunopathology.

Clinical and epidemiological profile of lichen striatus in children-Experience from a tertiary care hospital.

We analyzed records of 30 patients with lichen striatus (age < 18 years) in this retrospective study. Seventy percent were females and 30% were males with a mean age of diagnosis of 5.38 ± 4.22 years. The most common age group affected was 0-4 years. The mean duration of lichen striatus was 6.66 ± 4.22 months. Atopy was present in 9 (30%) patients. Although LS is a benign self-limited dermatosis, long-term prospective studies with a greater number of patients will help in better understanding of the disease including its etiopathogenesis and association with atopy.

[Lichen planus]. / Lichen planus.

Lichen planus is an inflammatory disorder of the skin and/or mucosa. Immune dysregulation, infections, environmental and genetic factors play a role in its pathogenesis. Clinically, there are 6 important distinctive manifestations. The mucosal subtypes manifest inside the mouth, oesophagus, genitalia and - although less often - the nose, ear canal, tear duct and conjuctiva. The non-mucosal subtypes occur on the skin, scalp (hair follicles) and nails. Patients may suffer from several subtypes of lichen planus. Unfamiliarity with the different manifestations may lead to a delay in diagnosis and thus to insecurity and distress in patients. The advice to all healthcare providers is to ask patients with lichen planus about symptoms of all subtypes and clinically inspect the skin and mucosa, or to refer the patient to a dermatologist.