Senescence in oral lichen planus as assessed by the immunohistochemical evaluation of senescence marker protein-30 (Regucalcin).

Background: Oral lichen planus is a T-cell-mediated chronic inflammatory disease affecting approximately 1% to 2% of the population, the etiology of which is currently unknown. The objectives of this study were to observe if senescence occurs in oral lichen planus, through the assessment of the immunohistochemical expression of a novel marker for senescence called Senescence marker protein-30 or regucalcin, and compare the expression to that in oral lichenoid reaction and non-specific inflammation. Subjects and Methods: The study material consisted of 30 cases of oral lichen planus, 15 cases of oral lichenoid reaction and 15 cases of non-specific inflammation. The number of positive cells in ten randomly selected high power fields were counted in the epithelium and the connective tissue separately and the mean was determined. Results: Mann-Whitney U test was used to statistically analyze if there was any significant difference in the expression of Senescence marker protein-30 between oral lichen planus, oral lichenoid reaction and non-specific inflammation. Even though a greater expression was seen in the oral lichen planus cases than oral lichenoid reaction, the difference in both the epithelium and connective tissue was not statistically significant. Conclusion: This study shows that in addition to the already known mechanisms like apoptosis and increased cell proliferation rates, the activated T-lymphocytes may also trigger a senescent change in the cells of oral lichen planus. As with the other mechanisms, this is also seen only in a small proportion of the cases.

Lichenoid dermatitis from immune checkpoint inhibitor therapy: An immune-related adverse event with mycosis-fungoides-like morphologic and molecular features.

Cutaneous immune-related adverse events (irAEs) are a known consequence of immune checkpoint inhibitor (ICI) therapy and may exhibit a spectrum of morphologic features both clinically and histologically. Lichenoid dermatitis associated with ICI therapy (LD-ICI) is the most frequently encountered histopathologic type of irAE biopsied by dermatologists. There is frequent clinical and histologic overlap between irAEs and several reactive and neoplastic dermatologic disorders; thus, clinical information is essential. LD-ICI with histologic, immunohistochemical, and molecular features typical of mycosis fungoides (MF) are unique. Here, we report a patient who developed LD-ICI with MF-like morphologic features with monoclonal T-cell receptor gene rearrangement on consecutive biopsies during ICI therapy. The development of monoclonal LD-ICI is important for clinicians and pathologists to recognize in patients receiving ICI therapy.

Immune response patterns in non-communicable inflammatory skin diseases.

Non-communicable inflammatory skin diseases (ncISD) such as psoriasis or atopic eczema are a major cause of global disease burden. Due to their impact and complexity, ncISD represent a major challenge of modern medicine. Dermatology textbooks describe more than 100 different ncISD based on clinical phenotype and histological architecture. In the last decades, this historical description was complemented by increasing molecular knowledge - and this knowledge is now being translated into specific therapeutics. Combining the enormous advances made in lymphocyte immunology and molecular genetics with clinical and histological phenotyping reveals six immune response patterns of the skin - type I immune cells cause the lichenoid pattern characterized by immune-mediated cell death of keratinocytes; type II immune cells underlie the eczematous pattern with impaired epidermal barrier, infection and eosinophils as well as the bullous pattern with loss of epithelial integrity; Th17 cells and ILC3 mediate the psoriatic pattern characterized by acanthosis, high metabolic activity and neutrophils; dysbalance of regulatory T cells causes either the fibrogenic pattern with rarefication of cells and dermal thickening or the granulomatous pattern defined by formation of granulomas. With more and more specific therapeutic agents approved, classifying ncISD also according to their immune response pattern will become highly relevant. This review defines the six immune response patterns of ncISD and highlights therapeutic strategies targeting key lymphocyte mediators.

PD-1 inhibitor-associated lichenoid inflammation with incidental suprabasilar acantholysis or vesiculation-Report of 4 cases.

BACKGROUND: Immune checkpoint agents targeting programmed cell death-1 protein (PD1) or cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) receptors are increasingly utilized in treatment of advanced malignancies. However, these immunotherapies are commonly associated with idiosyncratic cutaneous adverse reactions. Thus, recognition and awareness of these reactions are necessary. METHODS: We reviewed the skin biopsies of all patients on anti-PD1 therapy with or without ipilimumab who developed lichenoid inflammation and included those with microscopic suprabasal or intraepidermal clefts. RESULTS: Four patients presented with interface dermatitis with microscopic intraepidermal clefts. In 2 patients, the clefts were well developed and had some acantholytic cells while the other 2 appeared to be spongiosis or inflammation related. Immunofluorescence was negative in 1 patient. None of them had clinical findings in keeping with paraneoplastic pemphigus (PP) and the symptoms improved with either topical corticosteroid or withdrawal of immunotherapy. CONCLUSIONS: Lichenoid drug reaction occurring in patients receiving anti-PD1 therapy may be associated with microscopic suprabasal or intraepidermal clefting. The clinical course was similar to lichenoid drug reactions without clefting even though some lesions may resemble PP microscopically.

Differentiating regressed melanoma from regressed lichenoid keratosis.

BACKGROUND: Distinguishing regressed lichen planus-like keratosis (LPLK) from regressed melanoma can be difficult on histopathologic examination, potentially resulting in mismanagement of patients. OBJECTIVE: We aimed to identify histopathologic features by which regressed melanoma can be differentiated from regressed LPLK. METHODS: Twenty actively inflamed LPLK, 12 LPLK with regression and 15 melanomas with regression were compared and evaluated by hematoxylin and eosin staining as well as Melan-A, microphthalmia transcription factor (MiTF) and cytokeratin (AE1/AE3) immunostaining. RESULTS: (1) A total of 40% of regressed melanomas showed complete or near complete loss of melanocytes within the epidermis with Melan-A and MiTF immunostaining, while 8% of regressed LPLK exhibited this finding. (2) Necrotic keratinocytes were seen in the epidermis in 33% regressed melanomas as opposed to all of the regressed LPLK. (3) A dense infiltrate of melanophages in the papillary dermis was seen in 40% of regressed melanomas, a feature not seen in regressed LPLK. CONCLUSIONS: In summary, our findings suggest that a complete or near complete loss of melanocytes within the epidermis strongly favors a regressed melanoma over a regressed LPLK. In addition, necrotic epidermal keratinocytes and the presence of a dense band-like distribution of dermal melanophages can be helpful in differentiating these lesions.

Sweat as an Efficient Natural Moisturizer.

Although recent research on the pathogenesis of allergic skin diseases such as atopic dermatitis has focused on defects in skin genes important for maintaining skin barrier function, the fact that excreted sweat has an overwhelmingly great capacity to increase skin surface hydration and contains moisturizing factors has long been ignored: the increase in water loss induced by these gene defects could theoretically be compensated fully by a significant increase in sweating. In this review, the dogma postulating the detrimental role of sweat in these diseases has been challenged on the basis of recent findings on the physiological functions of sweat, newly recognized sweat gland-/duct-related skin diseases, and therapeutic approaches to the management of these diseases. We are now beginning to appreciate that sweat glands/ducts are a sophisticated regulatory system. Furthermore, depending on their anatomical location and the degree of the impairment, this system might have a different function: sweating responses in sweat glands/ducts located at the folds in hairy skin such as on the trunk and extremities could function as natural regulators that maintain skin hydration under quiescent basal conditions, in addition to the better-studied thermoregulatory functions, which can be mainly mediated by those at the ridges. The normal functioning of sweat could be disturbed in various inflammatory skin diseases. Thus, we should recognize sweating disturbance as an etiologic factor in the development of these diseases.

Genomewide miRNA profiling of oral lichenoid disorders and oral squamous cell carcinoma.

OBJECTIVE: To dissect the aberrant microRNA profile of oral lichenoid disorders (OLD) by analyzing the larger set of OLD samples tested so far. MATERIALS AND METHODS: MicroRNA expression profiles were assessed using TLDA card in 32 samples (16 OLD, 8 OSCC, and 8 control). The findings were validated using RT-qPCR in an independent cohort of 91 samples. RESULTS: We identified 20 differentially expressed microRNAs in OLD, of which several are functionally related to cell proliferation, response to organic substances, or immune processes. Further validation of the top-ranked microRNAs revealed that they were all aberrantly expressed in OLD. CONCLUSION: We have identified a new microRNA signature associated with OLD that may provide a meaningful basis for better understanding the physiopathology of the disease. In addition, we validated seven microRNAs whose expression was shown to be higher in OLD tissue in comparison with the control and OSCC tissues.

Lichen striatus versus linear lichen planus: a comparison of clinicopathological features, immunoprofile of infiltrated cells, and epidermal proliferation and differentiation.

BACKGROUND: Lichen striatus (LS) and linear lichen planus (LLP) are separate uncommon disorders belonging to linear inflammatory dermatoses. The immunotyping of inflammatory cells has been investigated in LS and lichen planus (LP), but epidermal proliferation and differentiation have little been described in LS and LLP. METHODS: The clinical and pathological data of eight patients with LS and seven with LLP were retrospectively collected. Immunotyping of infiltrated cells and expression of Ki-67, K16, involucrin, and filaggrin were stained by immunohistochemistry in skin lesions of these patients and normal skin of eight healthy controls. RESULTS: Dermal infiltrates contained primarily CD3+ and CD68+ cells in three groups. CD4+ cells were predominantly located in the perivascular area, while CD8+ cells were frequently close to the junctional zone. Compared with control skin, epidermal and dermal CD1a+ cells, and dermal CD3+, CD4+, CD8+, and CD68+ cells were increased in LS and LLP (P < 0.05), while Ki-67+ cells were significantly high in LLP (P < 0.05) but not in LS. K16 and involucrin expression in LLP were more extensive than in LS, and filaggrin expression was similar between both entities. CONCLUSIONS: Our results indicate that the predominance of CD8+ cells and increased epidermal proliferation and abnormal keratinization are present in both dermatoses, although the levels of the above indexes are mild in LS as compared to LLP. These two entities might be due to the interaction of infiltrated cells and keratinocytes, and CD8+ cells could play a pivotal role in their pathogenesis.

Evaluation of prolidase activity and oxidative stress in patients with oral lichen planus and oral lichenoid contact reactions.

OBJECTIVE: The aim of this study was to evaluate prolidase activity and oxidative stress in patients with oral lichen planus (OLP) and oral lichenoid contact reactions (OLCR) using serum and salivary samples and to compare these biomarkers with each other as well as with a group of healthy subjects in order to be able to opine their role in the estimation of OLP and OLCR. PATIENTS AND METHODS: Eighteen recently diagnosed patients with OLP, 32 patients with OLCR and 18 healthy controls with matched periodontal status were recruited to the study. Prolidase activity, lipid peroxidation product malondialdehyde (MDA), sialic acid (SA), and advanced oxidation protein products (AOPPs) levels in both serum and saliva were determined. Additionally, salivary flow rate and its buffering capacity were estimated. Statistical analyses were performed using the chi-square test, t-test, Mann-Whitney U-test, and Spearman's rho correlation coefficient. RESULTS: No statistically significant differences were observed between the study groups and the control group regarding to the basic characteristics and the periodontal status (P > 0.05). There were no statistically significant differences between OLP and OLCR groups regarding to the distribution of lesions' type, severity, and location (P > 0.05). No significant differences were found between the two study groups with regard to Prolidase activity, MDA, SA, and AOPPs (P ˃ 0.05), whereas statistically significant differences were found between the two study groups and the control group with regard to all evaluated parameters except of serum prolidase (P ˂ 0.01). Moderate correlation was found between salivary MDA and the OLP/OLCR lesion severity, whereas a weak correlation was observed between serum SA and the OLP/OLCR lesion severity (P ˂ 0.05). CONCLUSIONS: The findings of this study suggest an increased prolidase activity and oxidative stress and imbalance in the antioxidant defense system in biological fluids of patients with OLP and OLCR when compared with the healthy subjects. Both OLP and OLCR patients revealed almost similar prolidase activity and oxidative stress levels although these two conditions have different etiopathogenesis.

p53 expression in oral lichenoid lesions and oral lichen planus.

The aim of this article was to compare the expression of p53 protein in oral lichen planus (OLP) and oral lichenoid reaction (OLR). The study population consisted of 65 patients--31 diagnosed with OLP and 34 with OLR. The results showed more p53 positive cases in the OLP group than in the OLR group. However, the difference between the 2 groups was not statistically significant (P = 0.114). The most common immunolocalization was observed at the basal cell layer. Due to the chance of potential future malignancy, follow-up for all cases is recommended.

Alergia a la oruga procesionaria del pino / Allergy to pine processionary moth larvae

No disponible

Sox10 is expressed in primary melanocytic neoplasms of various histologies but not in fibrohistiocytic proliferations and histiocytoses.

BACKGROUND: Sox10 is a transcription factor associated with neural crest development. Its expression has been reported in melanocytes and peripheral nerve sheath cells and their associated tumors. OBJECTIVE: To assess Sox10 sensitivity in benign and malignant melanocytic neoplasms of various histologic subtypes and to discern the specificity of Sox10 in distinguishing between melanocytic neoplasms and fibrohistiocytic and histiocytic mimickers. METHODS: Sox10 expression was examined by immunohistochemistry in 145 cases of formalin-fixed paraffin-embedded tissue, including benign and malignant melanocytic lesions of various histologies and stages (n = 83), fibrohistiocytic and histiocytic lesions (n = 33), and peripheral nerve sheath tumors (n = 19), among others (n = 10). RESULTS: Immunoreactivity with Sox10 was observed in 100% (83/83) of benign and malignant melanocytic lesions of various subtypes, as well as in 100% (19/19) of benign and malignant peripheral nerve sheath lesions. Among the fibrohistiocytic proliferations and histiocytoses examined, Sox10 was negative in all cases (0/33). Sox10 expression did not vary by histologic subtype in nevi or melanoma; however, both the percentage of tumor nuclei demonstrating Sox10 expression and the intensity of expression were inversely correlated with malignant potential (nevi, melanoma in situ, invasive and metastatic melanoma) (P < .001, P = .016, respectively). Malignant peripheral nerve sheath tumors also showed decreased mean Sox10 expression and decreased intensity of expression when compared with benign counterparts (P < .001, P = .021, respectively). LIMITATIONS: This is a retrospective study with 145 cases included. CONCLUSIONS: Sox10 is a highly sensitive marker for melanocytic proliferations and may be useful diagnostically when the differential diagnosis includes fibrohistiocytic and histiocytic proliferations demonstrating S100 expression.

Nests with numerous SOX10 and MiTF-positive cells in lichenoid inflammation: pseudomelanocytic nests or authentic melanocytic proliferation?

Pseudomelanocytic nests in the setting of lichenoid inflammation can mimic atypical melanocytic proliferations. Both melanocytic and cytokeratin immunohistochemical stains may be utilized to differentiate these entities. Unlike true melanocytic nests, pseudomelanocytic nests contain Melanoma Antigen Recognized by T-cells 1 (MART-1)/ Melan-A-positive cells and cells positive for pan-cytokeratins, CD3 and/or CD68. Recently, rare (1-2 cells/nest) microphthalmia- associated transcription factor (MiTF)-positive cells were also reported in pseudomelanocytic nests. We present a 48-year-old man with a 2 × 3 cm violaceous to hyperpigmented, non-blanching, polygonal patch on the neck. Histopathology showed focal epidermal atrophy, irregularly distributed junctional nests and a lichenoid infiltrate with colloid bodies. Immunoperoxidase studies revealed occasional pan-cytokeratin and MART-1/Melan-A-positive staining in nests as well as focal S-100 protein-positive cells. Importantly, the majority of nests showed numerous cells positive for MiTF and SOX10 (>2 cells/nest and some the majority of cells). This combined staining pattern confounds the above-described immunohistochemical distinction between pseudo and true melanocytic nests. Clinically felt to represent unilateral lichen planus pigmentosus/erythema dyschromicum perstans and not malignant melanoma in situ, this lesion highlights the importance of clinicopathologic correlation and suggests either a new melanocytic entity or a novel pattern of benign melanocytic reorganization in a subset of lichenoid dermatitides.

An immunohistochemical analysis of pseudomelanocytic nests mimicking melanoma in situ: report of 2 cases.

Several case reports have discussed the difficulty in differentiating junctional pseudomelanocytic nests as a result of lichenoid inflammation from a true melanocytic neoplasm. Even immunohistochemistry can be misleading in these cases with both Melan-A and Mart-1 frequently resulting in false positivity as a result of nonspecific labeling of nonmelanocytic cells containing melanosomes. We present a series of 2 similar cases which were initially misdiagnosed as melanoma in situ likely as a result of Mart-1 positivity of the pseudomelanocytic nests. However, in our review, a significant lichenoid reaction was apparent at the dermal-epidermal junction. Staining with microphthalmia-associated transcription factor (MITF) showed a normal density of melanocytes along the dermal-epidermal junction and failed to uniformly label the Mart-1-positive pseudomelanocytic nests. In both patients, medications frequently resulting in fixed drug eruptions were identified, and a final diagnosis of fixed drug eruption was rendered in both cases. In light of these findings we suggest MITF is a more useful marker for evaluating lentiginous proliferations along the dermal-epidermal junction particularly when dealing with the differential diagnosis of lichenoid reaction with pseudomelanocytic nests versus melanoma in situ.

Paucity of intraepidermal FoxP3-positive T cells in cutaneous T-cell lymphoma in contrast with spongiotic and lichenoid dermatitis.

BACKGROUND: FoxP3 is the most specific available marker for regulatory T cells (Tregs). Tumor-associated FoxP3-positive Tregs have been identified in various neoplasms, including cutaneous T-cell lymphoma (CTCL). FoxP3 expression in CTCL varies across groups; few studies have compared CTCL with inflammatory conditions. METHODS: Lesional skin biopsies from 20 patients with CTCL [13 mycosis fungoides (MF); 7 Sézary syndrome (SS)] and 22 with inflammatory dermatoses (11 spongiotic; 11 lichenoid or interface) were examined for FoxP3 expression by immunohistochemistry. Epidermal FoxP3-positive lymphocytes were counted as a percentage of the total epidermal CD3-positive T-cell population. RESULTS: FoxP3-positive T cells composed the minority of infiltrate in all major categories. Lower numbers of epidermal FoxP3-positive T cells were observed in CTCL, particularly MF, than in inflammatory dermatoses (P < .001). CTCL neoplastic T cells did not express FoxP3. CONCLUSION: FoxP3-positive T cells are less frequently encountered in MF than in inflammatory dermatoses. FoxP3-positive T cells occur in higher proportions in the dermis than in the epidermis and probably correlate with coexisting inflammatory components. CTCL neoplastic cells do not typically express a Treg phenotype and are associated with low numbers of FoxP3-positive Tregs in the infiltrate. FoxP3 expression by immunohistochemistry may aid histologic evaluation of these conditions.

Melan-a-positive "pseudomelanocytic nests": a pitfall in the histopathologic and immunohistochemical diagnosis of pigmented lesions on sun-damaged skin.

We encountered recently 3 cases with a histopathologic diagnosis of melanoma in situ on sun-damaged skin (male = 2, female = 1; median age: 59 years; range: 52-60 years). The diagnosis was based mainly on the finding of actinic elastosis in the dermis and increased number of melanocytes in the epidermis and was confirmed by strong positivity for Melan-A in single cells and in small nests ("pseudomelanocytic nests"), located at the dermoepidermal junction. Indeed, examination of slides stained with hematoxylin and eosin revealed the presence of marked hyperpigmentation and small nests of partially pigmented cells at the dermoepidermal junction, positive for Melan-A. The histologic and especially the immunohistochemical features were indistinguishable from those of melanoma in situ on chronic sun-damaged skin. In addition, a variably dense lichenoid inflammation was present. Clinicopathologic correlation, however, showed, in all patients, the presence of a lichenoid dermatitis (phototoxic reaction, 1 case; lichen planus pigmentosus, 1 case; and pigmented lichenoid keratosis, 1 case). Our cases clearly show the histopathologic pitfalls represented by lichenoid reactions on chronic sun-damaged skin. Immunohistochemical investigations, especially if performed with Melan-A alone, may lead to confusing and potentially disastrous results. The unexpected staining pattern of Melan-A in cases like ours raises concern about the utility of this antibody in the setting of a lichenoid tissue reaction on chronic sun-damaged skin. It should be underlined that pigmented lesions represent a paradigmatic example of how immunohistochemical results should be interpreted carefully and always in conjunction with histologic and clinical features.

CXCR3 <-> ligand-mediated skin inflammation in cutaneous lichenoid graft-versus-host disease.

BACKGROUND: Lichenoid graft-versus-host disease (liGVHD) histologically shares several common features with other lichenoid dermatoses, such as cutaneous lupus erythematosus and lichen planus (LP), which collectively show a junctional infiltrate of cytotoxic lymphocytes with liquefaction of the basal layer ("interface dermatitis"). Because recent studies have shown a role for type I interferon (IFN)-associated inflammation, including lymphocyte recruitment via CXCR3 <-> ligand interaction in cutaneous lupus erythematosus and LP, we hypothesized that similar mechanisms might also be involved in liGVHD. METHODS: Ten representative lesional skin biopsies taken from patients with different subsets of chronic cutaneous graft versus host disease (GvDH) were recovered from the authors' archives. Eight LP specimens and 5 punch biopsies taken from healthy skin were analyzed for control purposes. Immunohistochemistry was performed to characterize the lesional infiltrate (CD3, CD4, CD8, CD20, CD56, or CD68), to analyze type I IFN signaling (MxA), and to investigate expression of the IFN-inducible chemokines CXCL9 and CXCL10 and their ligand CXCR3. In situ hybridization was performed to visualize IFNalpha expression on the mRNA level. RESULTS: Our analyses revealed striking similarities between the inflammatory pattern seen in LP and liGVHD. Both disorders presented with a predominantly T-cellular inflammation with CD8(+) lymphocytes affecting the basal epidermal layer. The majority of lesional lymphocytes expressed the chemokine receptor CXCR3. The corresponding chemokines CXCL9 and CXCL10 were found in the epidermis and within the inflammatory infiltrate. Analyses of MxA and IFNalpha mRNA expression supported a role for type I IFNs in these conditions. LIMITATIONS: This study was limited by the number of well characterized cases in our archives. In situ hybridization was realizable only in single cases. CONCLUSION: Our results support the hypothesis that CXCR3 <-> ligand-mediated lymphocyte recruitment is involved in cutaneous liGVHD. The fact that CXCL10 was seen in precisely those areas with extensive liquefaction of the basal epidermis supports a role of this chemokine for the development of the typical histologic "interface" pattern.

Lupus erythematosus: clinical and histopathological study of oral manifestations and immunohistochemical profile of epithelial maturation.

BACKGROUND: Lupus erythematosus (LE) is an autoimmune disease of unknown cause. Prevalence of oral involvement in patients with LE is uncertain but may vary from 9 to 45% in patients with systemic disease and from 3 to 20% in patients with chronic cutaneous involvement. METHODS: Incidence of oral lesions of LE and their clinical aspects were investigated. Their histopathologic features were analyzed, and the status of epithelial maturation was assessed through the expression patterns of cytokeratins. RESULTS: Twenty-six patients (from 188 examined) presented oral lesions of LE. Most of them were females (19) with systemic disease (11). Clinical aspects of these lesions varied, and lips and buccal mucosa were most affected. Histologically, lesions revealed lichenoid mucositis with perivascular infiltrate and thickening of basement. Cytokeratins profile showed hyperproliferative epithelium, with expression of CK5/6, and CK14 on all epithelial layers, CK16 on all suprabasal layers and CK10 on prickle cell layers only. CONCLUSIONS: Oral lesions of LE show a variety of aspects, and their microscopic features are of a lichenoid mucositis with deep inflammatory infiltrate. Cytokeratins expression patterns are of hyperproliferative epithelium, and this phenomenon must be analyzed in relation to the inflammatory cytokines for a better understanding of the mechanisms of the disease.