Punch Biopsy Extraction With Fingers.

Punch biopsies are commonly used in dermatology for diagnosing skin diseases. Traditional methods involve the use of forceps, skin hooks, and scissors, which add to health care costs. The technique described here offers a cost-effective and efficient alternative for obtaining specimens.

A Protocol for the Automated Assessment of Cutaneous Pathology in a Mouse Model of Hemichannel Dysfunction.

In this chapter, we provide detailed instructions to perform quantitative reflectance imaging in a mouse model of a rare epidermal disorder caused by hyperactive connexin 26 hemichannels. Reflectance imaging is a versatile and powerful tool in dermatology, offering noninvasive, high-resolution insights into skin pathology, which is essential for both clinical practice and research. This approach offers several advantages and applications. Unlike traditional biopsy, reflectance imaging is noninvasive, allowing for real-time, in vivo examination of the skin. This is particularly valuable for monitoring chronic conditions or assessing the efficacy of treatments over time, enabling the detailed examination of skin morphology. This is crucial for identifying features of skin diseases such as cancers, inflammatory conditions, and infections. In therapeutic applications, reflectance imaging can be used to monitor the response of skin lesions to treatments. It can help in identifying the most representative area of a lesion for biopsy, thereby increasing the diagnostic accuracy. Reflectance imaging can also be used to diagnose and monitor inflammatory skin diseases, like psoriasis and eczema, by visualizing changes in skin structure and cellular infiltration. As the technology becomes more accessible, it has potential in telemedicine, allowing for remote diagnosis and monitoring of skin conditions. In academic settings, reflectance imaging can be a powerful research tool, enabling the study of skin pathology and the effects of novel treatments, including the development of monoclonal antibodies for therapeutic applications.

A case report of multicentric reticulohistiocytosis with atypical cutaneous presentation.

Multicentric reticulohistiocytosis (MRH) is a rare systemic disorder characterized by histiocytic hyperplasia that mainly involves the skin, mucous membranes, and joints. The typical clinical features include papules, nodules, and arthritis. MRH lesions are relatively extensive but small and scattered. Joint inflammation is characterized by diffuse symmetric polyarthritis as the first symptom, which can be severe and disabling due to destructive joint changes. MRH is easily misdiagnosed in clinical practice. Here, we report the case of an elderly male patient who presented with polyarticular pain in the hip and interphalangeal joints as the first manifestation, followed by the development of large, isolated, bulging skin nodules, which are atypical MRH lesions. This is rare in all MRH case reports, and we made the correct diagnosis by combining skin histopathology, immunohistochemistry, and other clinical examinations. We performed surgical treatment on the local skin lesions of this patient. This case suggests that clinicians should actively correlate the condition and accurately diagnose MRH when encountering atypical skin changes or other diseases as the first symptom and explore the mechanisms of MRH and other clinical manifestations.

Resolution of painful trichodysplasia spinulosa with topical cidofovir: case report.

Purpose: Trichodysplasia spinulosa (TS) is a rare, disfiguring skin condition which presents with widespread asymptomatic or pruritic, skin-colored papules with white protruding keratin spiculations in immunocompromised individuals. Due to its rarity, there is little data to guide treatment decisions. The purpose of this article is to report a case of TS that completely resolved after treatment with topical cidofovir.Materials and methods: A 19-year-old immunosuppressed female presented with widespread painful, itchy bumps on the nose and face. Upon examination, there were erythematous papules with hyperkeratinized spicules affecting the central face. Biopsy of the lesions was consistent with TS which was confirmed via PCR analysis. The tenderness of this patient's eruption was highly atypical for TS. Once daily topical application of compounded 1% cidofovir cream was prescribed.Results: The patient's symptoms resolved completely after 4 weeks of therapy with topical cidofovir 1% cream, without reduction of immunosuppression.Conclusions: Topical cidofovir 1% cream may be a valuable treatment for this rare disease.

Facial cutaneous Rosai-Dorfman disease: a case report.

BACKGROUND: Rosai-Dorfman disease (RDD) is a form of non-Langerhans cell histiocytosis in which the activated histiocytes of the lymph nodes and other organs begin to accumulate following excessive production. Bilateral, massive, and painless lymphadenopathy are classic presentations. Systemic RDD is already known to be a rare condition, but isolated cutaneous RDD is extremely rare. We presented a rare and unusual presentations of a disease. CASE PRESENTATION: A 35-year-old Thai female with a 6-month history of a small acne-like lesion that rapidly progressed to 5 cm tumor-like lesions on the face within 3 months. Tissue histology showed a dense dermal infiltration of histiocytes with emperipolesis phenomenon. Immunohistochemistry was positive for S100 protein and CD68 and negative for CD1a. Oral prednisolone (50 mg/day) was initiated with a favorable outcome at the one-month follow-up. However, prednisolone yielded a partial response at 2-month follow-up, leading to application of another modality. CONCLUSION: Although cutaneous Rosai-Dorfman disease is considered benign and well medical responded disease, patients with atypical presentation and rapid growing lesion may necessitate aggressive multimodal treatment.

Skin and lung fibrosis induced by bleomycin in mice: a systematic review.

OBJECTIVE: Scleroderma, or systemic sclerosis (SSc), is a chronic autoimmune connective disease with an unknown etiology and poorly understood pathogenesis. The striking array of autoimmune, vascular, and fibrotic changes that develop in almost all patients makes SSc unique among connective tissue diseases. Although no animal model developed for SSc to date fully represents all features of human disease, some animal models that demonstrate features of SSc may help to better understand the pathogenesis of the disease and to develop new therapeutic options. In this review, we aimed to evaluate skin fibrosis and lung involvement in a bleomycin (BLM)-induced mouse model and to evaluate the differences between studies. METHODS: A systematic literature review (PRISMA guideline) on PubMed and EMBASE (until May 2023, without limits) was performed. A primary literature search was conducted using the PubMed and EMBASE databases for all articles published from 1990 to May 2023. Review articles, human studies, and non-dermatological studies were excluded. Of the 38 non-duplicated studies, 20 articles were included. RESULTS: Among inducible animal models, the BLM-induced SSc is still the most widely used. In recent years, the measurement of tissue thickness between the epidermal-dermal junction and the dermal-adipose tissue junction (dermal layer) has become more widely accepted. CONCLUSIONS: In animal studies, it is important to simultaneously evaluate lung tissues in addition to skin fibrosis induced in mice by subcutaneous BLM application, following the 3R (replacement, reduction, and refinement) principle to avoid cruelty to animals.

Adenosine A2B receptor agonist improves epidermal barrier integrity in a murine model of epidermal hyperplasia.

Adenosine regulates multiple physiological processes through the activation of four receptor subtypes, of which the A2B adenosine receptor (A2BAR) has the lowest affinity for adenosine. Being the adenosine receptor subtype most prominently expressed in epidermis, we recently described the antiproliferative and anti-inflammatory effect of the selective A2BAR agonist BAY60-6583 (BAY) in human keratinocytes stimulated with 12-O-tetradecanoylphorbol-13-acetate (TPA), so we sought to establish the effect of topical application of BAY in a model of murine epidermal hyperplasia. Topical application of BAY (1 or 10 µg/site) prevented the inflammatory reaction and skin lesions induced by TPA, minimizing hyperproliferation and acanthosis, as well as the expression of specific markers of proliferative keratinocytes. On the other hand, pre-treatment with the selective A2BAR antagonist, PSB-1115 (PSB, 5 or 50 µg/site) reversed these beneficial effects. Additionally, BAY application normalized the expression of epidermal barrier proteins, whose integrity is altered in inflammatory skin diseases, while treatment with the antagonist alone worsened it. Our results, besides confirming the anti-inflammatory and antiproliferative effects of the A2BAR agonist, further demonstrate a role of A2BAR activation to preserve the epidermal barrier. Therefore, the activation of A2BAR may constitute a possible new pharmacological target for the treatment of skin inflammatory diseases such as psoriasis.

Melatonin restores DNFB-induced dysbiosis of skin microbiota in a mouse model of atopic dermatitis.

BACKGROUND: The epidermic microbiota plays crucial roles in the pathogenesis of atopic dermatitis (AD), a common inflammatory skin disease. Melatonin (MLT) has been shown to ameliorate skin damage in AD patients, yet the underlying mechanism is unclear. METHODS: Using 2,4-dinitrofluorobenzene (DNFB) to induce an AD model, MLT intervention was applied for 14 days to observe its pharmaceutical effect. Skin lesions were observed using HE staining, toluidine blue staining and electron microscopy. Dermal proinflammatory factor (IL-4 and IL-13) and intestinal barrier indices (ZO1 and Occludin) were assessed by immunohistochemistry and RT-qPCR, respectively. The dysbiotic microbiota was analyzed using 16S rRNA sequencing. RESULTS: MLT significantly improved skin lesion size; inflammatory status (mast cells, IgE, IL-4, and IL-13); and the imbalance of the epidermal microbiota in AD mice. Notably, Staphylococcus aureus is the key bacterium associated with dysbiosis of the epidermal microbiota and may be involved in the fine modulation of mast cells, IL-4, IL-13 and IgE. Correlation analysis between AD and the gut revealed that intestinal dysbiosis occurred earlier than that of the pathological structure in the gut. CONCLUSION: Melatonin reverses DNFB-induced skin damage and epidermal dysbiosis, especially in S. aureus.

Overview of Neutrophilic Biology, Pathophysiology, and Classification of Neutrophilic Dermatoses.

Neutrophilic dermatoses are a group of inflammatory skin conditions characterized by a neutrophilic infiltrate on histopathology with no evidence of infection. These conditions present with a wide range of clinical manifestations, including pustules, bullae, abscesses, papules, nodules, plaques, and ulcers. The classification of neutrophilic dermatoses is based on the localization of neutrophils in the skin. The pathogenic mechanisms of neutrophilic dermatoses involve autoinflammation, neutrophilic dysfunction, clonal somatic mutation and differentiation of the myeloid precursors as encountered in myeloid neoplasm.

Macular amyloidosis diagnostic outcomes of skin biopsy: A systematic review.

Macular amyloidosis (MA) is a primary localized cutaneous amyloidosis, characterized by amyloid deposition in the papillary dermis. The clinical presentation includes pruritic hyperpigmented macules and patches with a reticulated or rippled pattern, primarily found on the upper back and extremities. Biopsy is an essential diagnostic tool for confirming MA. This systematic review focused on the biopsy outcomes in patients diagnosed with MA.

Giant cell collagenomas associated with Cowden syndrome: A case report.

Storiform collagenoma, also known as sclerotic fibroma, is a relatively rare benign cutaneous tumor consisting of a proliferation of fibroblasts that shows increased production of type I collagen. It may appear as a solitary, sporadic lesion, or, especially when multiple, associated with Cowden syndrome. Giant cell collagenoma has a histopathologic appearance similar to that of storiform collagenoma with the addition of floret-type giant cells. Herein, we report the finding of multiple giant cell collagenomas arising in an individual with Cowden syndrome. In a review of the published literature, this histopathologic variant appears to be rarely observed in association with Cowden syndrome.

Neutrophilic dermatoses as a manifestation of a systemic lupus erythematosus flare.

Neutrophilic dermatoses (NDs) refer to a group of cutaneous conditions histologically characterized by the dense accumulation of neutrophils in the skin in the absence of infection. NDs have been associated with underlying autoimmune connective tissue disorders (CTDs) such as systemic lupus erythematosus (SLE), Sjogren's syndrome, and dermatomyositis. We describe a case of neutrophilic dermatoses as a manifestation of a SLE flare.

Diverse macrophage populations contribute to distinct manifestations of human cutaneous graft-versus-host disease.

BACKGROUND: Graft-versus-host disease (GvHD) is a major life-threatening complication of allogeneic haematopoietic stem cell transplantation (HSCT), limiting the broad application of HSCT for haematological malignancies. Cutaneous GvHD is described as a post-transplant inflammatory reaction by skin-infiltrating donor T cells and remaining recipient tissue-resident memory T cells. Despite the major influence of lymphocytes on GvHD pathogenesis, the complex role of mononuclear phagocytes (MNPs) in tissues affected by GvHD is increasingly appreciated. OBJECTIVES: To characterize the identity, origin and functions of MNPs in patients with acute cutaneous GvHD. METHODS: Using single-cell RNA sequencing and multiplex tissue immunofluorescence, we identified an increased abundance of MNPs in skin and blood from 36 patients with acute cutaneous GvHD. In cases of sex-mismatched transplantation, we used expression of X-linked genes to detect rapid tissue adaptation of newly recruited donor MNPs resulting in similar transcriptional states of host- and donor-derived macrophages within GvHD skin lesions. RESULTS: We showed that cutaneous GvHD lesions harbour expanded CD163+ tissue-resident macrophage populations with anti-inflammatory and tissue-remodelling properties including interleukin-10 cytokine production. Cell-cell interaction analyses revealed putative signalling to strengthen regulatory T-cell responses. Notably, macrophage polarization in chronic cutaneous GvHD types was proinflammatory and drastically differed from acute GvHD, supporting the notion of distinct cellular players in different clinical GvHD subtypes. CONCLUSIONS: Overall, our data reveal a surprisingly dynamic role of MNPs after HSCT. Specific and time-resolved targeting to repolarize this cell subset may present a promising therapeutic strategy in combatting GvHD skin inflammation.

Assessment of specificity of dermatopathologic criteria for IgG4-related skin disease.

BACKGROUND: IgG4-related disease (IgG4-RD) represents a recently characterized multisystemic fibroinflammatory condition that can manifest a spectrum of skin findings (IgG4-related skin disease; IgG4-RSD). Histopathologic and immunohistochemical criteria have been proposed; however, the specificity of these criteria merits scrutiny given the potential histopathologic overlap of IgG4-RSD and both neoplastic and inflammatory skin conditions featuring lymphoplasmacytic infiltrates (IgG4-RSD mimics). This study sought to assess the specificity of the criteria by quantifying the frequency by which an expanded spectrum of IgG4-RSD mimics meet proposed thresholds. METHODS: Following IRB approval, a total of 69 cases of IgG4-RD mimics, representing 14 different diagnoses featuring plasma cells, were reviewed and analyzed for the following histopathologic and immunohistochemical features: (i) maximum IgG4+ count/high-powered field (hpf) >200; (ii) IgG4/IgG ratio >0.4 averaged over 3 hpfs; (iii) IgG4+ count >10 per hpf. RESULTS: Screening for IgG4-RSD by histopathologic criteria demonstrated the high frequency of lymphoplasmacytic infiltrates, contrasted with the rarity of storiform fibrosis (only one case of erythema elevatum diutinum [EED]) and obliterative phlebitis (0 cases). By immunohistochemical criteria, the analysis revealed that no cases exceeded 200 IgG4+ cells; 13% (9/69) cases demonstrated an IgG4/IgG ratio of >0.4 averaged over 3 hpfs; and 23% (16/69) cases demonstrated a mean IgG4+ count of >10 per hpf. CONCLUSION: Application of proposed IgG4-RSD histopathologic criteria to an expanded spectrum of potential IgG4-RSD mimics (to include cutaneous marginal zone lymphoma, syphilis, necrobiosis lipoidica, lichen sclerosus, ALHE, psoriasis, lymphoplasmacytic plaque, EED, and erosive pustular dermatosis), highlights the relative nonspecificity of lymphoplasmacytic infiltrates contrasted with the stringency of storiform fibrosis and obliterative fibrosis. Furthermore, an IgG4+ cell count of >10 per hpf and an IgG4/IgG ratio of >0.4 are not specific to IgG4-RSD alone. In the appropriate clinical context for IgG4-RSD, histopathologic features still represent the entry threshold for diagnosis consideration, which then allows for further screening by immunohistochemical criteria.

CD27/CD70 pathway activation in primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder.

Primary cutaneous CD4+ small or medium T-cell lymphoproliferative disorder (PCSM-LPD) is a clonal T-cell proliferation disease confined to the skin. PCSM-LPD shares expression of T follicular helper (Tfh) cell markers with various mature T-cell lymphomas. However, the benign presentation of PCSM-LPD contrasts the clinical behavior of other Tfh-lymphomas. The aim of our study was to delineate the molecular similarities and differences between PCSM-LPD and other Tfh-derived lymphomas to explain the clinical behavior and unravel possible pathological mechanisms. We performed targeted next-generation sequencing of 19 genes recurrently mutated in T-cell neoplasms in n = 17 PCSM-LPD with high and in n = 21 PCSM-LPD with low tumor cell content. Furthermore, gene expression profiling was used to identify genes potentially expressed in the PD1-positive (PD1+) neoplastic cells. Expression of some of these genes was confirmed in situ using multistain immunofluorescence. We found that PCSM-LPD rarely harbored mutations recurrently detected in other T-cell neoplasms. PCSM-LPD is characterized by the invariable expression of the T-cell-receptor-associated LCK protein. CD70 and its ligand CD27 are co-expressed on PD1+ PCSM-LPD cells, suggestive of autoactivation of the CD70 pathway. In conclusion, PCSM-LPD differs from disseminated lymphomas of Tfh origin by their mutation profile. Activation of CD70 signaling also found in cutaneous T-cell lymphoma represents a potential driver of neoplastic proliferation of this benign neoplasia of Tfh. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Successful treatment with baricitinib of linear morphea following the lines of Blaschko mimicking lichen striatus.

Linear morphea, also known as linear scleroderma, is a localized form of scleroderma characterized by the presence of lesions that follow a linear distribution pattern. Apart from the typical inflammation and fibrosis of the skin, the linear subtype of morphea often affects underlying structures such as muscles and bones, which can lead to functional limitations. Lichen striatus, a linear inflammatory skin condition, primarily affects children aged 5 to 15 years. Interestingly, both diseases can exhibit lesions that follow the lines of Blaschko. Here we report a case with linear morphea following the lines of Blaschko mimicking lichen striatus in a 4-year-old child. This unique case represents the first documented instance of linear morphea exhibiting a precise Blaschko pattern and being successfully treated with baricitinib. The patient received oral baricitinib at a daily dosage of 2 mg for a duration of 1 year, resulting in remarkable improvement. The majority of the lesions softened, and there was no significant disease progression or occurrence of adverse events throughout the treatment period. Recognizing linear morphea at an early stage is of utmost importance in ensuring effective treatment and preventing disfiguring sequelae. Patients suspected of lichen striatus should also be closely followed and linear morphea should be excluded during the follow-up. The recent breakthrough in the application and the safety of baricitinib in scleroderma is also reviewed.