Elastic fiber pattern in scleroderma/morphea

Histopathologic spectrum of morphea: a single-center retrospective study

Morphea is a rare autoimmune disease that often affects skin and subcutaneous tissues. The aim of this study was to determine the association between patient demographic parameters, lesion site, clinical subtype of morphea, and histological findings. Between 2016 and 2022, we investigated 78 patients with morphea at the Department of Pathology, Prof. Dr. Cemil Taşcıoğlu City Hospital in Turkey. Case-specific hematoxylin and eosin stain slides were obtained from the pathology archive and assessed blindly by two pathologists. Flattening of rete ridges, location of inflammatory infiltrate, grade of inflammatory infiltrate, presence of plasma cells, presence of eosinophils, homogenization of dermal collagen, decrease of skin appendages, basal pigmentation and melanin incontinence were evaluated. Statistical analyses were performed using SPSS Statistics v.20 (IBM, Armonk, NY, USA). The most common clinical presentation was plaque type (87.5%), while histopathological findings included homogenization of dermal collagen (100%) and decrease of skin appendages (98.7%). Flattening of the rete ridges was observed in 46.2% of patients. Severity of the inflammatory infiltrate was found to be higher in these patients (p=0.028). Basal pigmentation was observed in 59% of patients. Line sign was more common in lower extremity lesions among all localizations (p=0.015). The histopathologic features of morphea are variable and confusing. Particularly, in cases with collagen homogenization, morphea should be considered in differential diagnosis with clinical correlation. In addition, the line sign could be helpful for identifying lesions located in the lower extremities.

[Juvenile localized scleroderma]

Juvenile scleroderma, often referred to as juvenile localized scleroderma or "morphea", is a rare inflammatory disease of the skin and skin-related structures, accompanied by local sclerosis and tissue fibrosis. Depending on the clinical manifestation, four different subtypes can be defined: limited, generalized, linear, and mixed. To prevent possible sequelae of the disease, the diagnosis should be made as early as possible and therapy should be initiated at specialized centers in multiprofessional pediatric and dermatologic collaboration. In this review, we present the main clinical, laboratory, and therapeutic characteristics of juvenile localized scleroderma and summarize recommendations.

Reduced fibrous capsule elastic fibers from biologic ECM-enveloped CIEDs in minipigs, supported with a novel compression mechanics model

BACKGROUND

Fibrous capsules (Fb) in response to cardiovascular implantable electronic devices (CIEDs), including a pacemaker (P) system, can produce patient discomfort and difficulties in revision surgery due partially to their increased compressive strength, previously linked to elevated tissue fibers.

OBJECTIVE

A preliminary study to quantify structural proteins, determine if biologic extracellular matrix-enveloped CIEDs (PECM) caused differential Fb properties, and to implement a realistic mechanical model.

METHODS

Retrieved Fb (-P and -PECM) from minipigs were subjected to biomechanical (shear oscillation and uniaxial compression) and histological (collagen I and elastin) analyses.

RESULTS

Fb-PECM showed significant decreases compared to Fb-P in: low strain-loss modulus (390 vs. 541 Pa) across angular frequencies, high strain-compressive elastic modulus (1043 vs. 2042 kPa), and elastic fiber content (1.92 vs. 3.15 μg/mg tissue). Decreases in elastin were particularly noted closer to the implant's surface (Fb-PECM = 71% vs. Fb-P = 143% relative to dermal elastin at mid-tangential sections) and verified with a solid mechanics hyperelasticity with direction-dependent fiber viscoelasticity compression simulation (r2 ≥ 98.9%).

CONCLUSIONS

The biologic envelope composed of decellularized porcine small intestine submucosa ECM for CIEDs promoted fibrous tissues with less elastic fibers. Novel compression modeling analyses directly correlated this singular reduction to more desirable subcutaneous tissue mechanics.

Histopathology of fluoroscopy-induced radiation ulcer: a case series study in comparison with morphea

BACKGROUND AND OBJECTIVES

Histopathologic diagnosis of fluoroscopy-induced radiation ulcer (FIRU) can be challenging if the past history of radiation exposure is unknown. Morphea is the most important differential diagnosis. This study was intended to identify clinical and pathologic features that can be used to distinguish FIRU from morphea.

PATIENTS AND METHODS

We performed a retrospective study on 25 specimens from 15 patients with FIRU and 21 specimens from 21 patients with morphea. Clinical findings and pathological features were analyzed.

RESULTS

Thirteen of 15 patients (86.7 %) with FIRU underwent angioplasty for coronary artery disease, and eleven patients had lesions in the right subscapular area. Compared with morphea, FIRU patients were more likely to display non-inflammatory infiltrates (28 %), bizarre fibroblasts (100 %), sclerosis (48 %), telangiectasia (96 %), vascular damage (64 %), and loss of skin appendages (100 %). In morphea, bizarre fibroblasts were rare (14 %), while telangiectasia (62 %) and loss of skin appendages (62 %) were variable. Loss of CD34+ cells and compression of elastic fibers could not be used to distinguish between FIRU and morphea.

CONCLUSIONS

Skin lesion in the right subscapular area with presence of bizarre fibroblasts, sclerosis, telangiectasia, and loss of cutaneous appendages as seen with histology are highly characteristic of the radiation damage associated with fluoroscopic angiography.

Histopathologic Spectrum of Morphea

ABSTRACT

Morphea is an autoimmune skin disease with protean clinical manifestations. Histologic features are similarly variable, and skin biopsies may be nondiagnostic. A single-institution retrospective cohort study was conducted. Morphea patients who had a biopsy in 2005-2015 were included, and a histopathological review was conducted by 2 pathologists. There were 51 biopsy specimens from 40 subjects. The most common histologic features were dermal sclerosis (90%), dermal thickening (78%), collagen homogenization (86%), a superficial and deep infiltrate (76%), a moderate-abundant inflammatory infiltrate (73%), and periadnexal fat loss/decreased skin appendages (71%). Twenty-four specimens were not diagnostic of morphea. In these specimens, the main clues to diagnosis included the presence of dermal sclerosis (79%), subtle collagen homogenization (75%), dermal thickening (58%), moderate-to-abundant plasma cells (50%), and perineural inflammation (50%). There were no statistically significant differences between active and inactive lesions, nor untreated and treated lesions. The histopathologic features of morphea are variable and a high proportion of biopsies are not diagnostic. Clinicians and pathologists should have a high degree of suspicion to correctly make the diagnosis of morphea.

Update on Management of Morphea (Localized Scleroderma) in Children

Juvenile localized scleroderma (morphea) is the predominant scleroderma in childhood which affects the skin and may extend to the underlying fascia, muscle, joints and bone. The assessment of activity and damage can be done with a validated instrument like LoSCAT. Disease classified as “low severity” which includes superficial plaque morphea can be treated with topical mid potent- potent steroids, tacrolimus, calcipotriol or imiquimod in combination with phototherapy. Methotrexate is recommended for linear, deep and generalized morphea. Steroids are effective in the early inflammatory stage and used in combination with methotrexate. Methotrexate is continued for at least 12 months after adequate response is achieved. Mycophenolate mofetil is given in cases where methotrexate is contraindicated or for those who do not respond to methotrexate. There are also reports of improvement of disease with ciclosporine and hydroxychloroquine. In severe cases, recalcitrant to standard therapy there may be a role for biologics, JAK inhibitors, and IVIG. Supportive measures like physiotherapy and psychiatric counseling are also important in the management of morphea. Orthopedic surgery and other measures like autologous fat transfer may be advocated once the disease is inactive.

Aplasia cutis congenita of the scalp: Histopathologic features and clinicopathologic correlation in a case series

BACKGROUND

Aplasia cutis congenita (ACC) is a rare and heterogeneous disorder characterized by congenital absence of skin. The scalp is the most commonly affected site and lesions may overlie deeper ectodermal abnormalities. The exact etiology is still unknown, and histopathologic features are poorly defined.

METHODS

A series of 10 cases from nine patients was analyzed to characterize the clinicopathologic spectrum and age-related changes of ACC of the scalp. Hematoxylin and eosin, S100, Elastica van Gieson, and Weigert elastic stains were performed, and clinical information was retrieved from archived medical files.

RESULTS

Patient ages ranged from 1 day to 39 years (median 57 months). All cases resembled deep-reaching scars with almost complete loss of all adnexal structures. Isolated residual hair follicles were present in 8/10 and sweat glands and ducts in 2/10 cases. The subcutis was thinned or absent. Elastic fibers were always more fragmented than in normal tissue, and the thickness and density increased over time. There was no gain of adnexal structures with increasing age.

CONCLUSIONS

ACC represents a congenital scarring alopecia with permanent loss of skin appendages. Histopathologic changes resemble a deep-reaching scar with fragmented elastic fibers and differentiate ACC from all other forms of non-traumatic congenital alopecias.

Polarized Microscopy in Lesions With Altered Dermal Collagen

Alterations in dermal collagen are noted in dermatofibroma, dermatofibrosarcoma protuberans, morphea, lichen sclerosus et atrophicus, hypertrophic scars, and keloids. The authors sought to determine whether variations in birefringence of collagen by polarized microscopy could be of help in diagnosing such conditions. Representative hematoxylin and eosin sections of 400 cases, including dermatofibroma, dermatofibrosarcoma protuberans, hypertrophic scars, keloid, morphea, and lichen sclerosus, were examined under polarized microscopy. Distinct patterns of birefringence of collagen for each disease were noted under polarized microscopy. This study highlights the use of polarized microscopy as adjunctive tool in differentiating different diseases with collagen alteration.

Altered Dermal Fibroblasts in Systemic Sclerosis Display Podoplanin and CD90

Tissue injury triggers the activation and differentiation of multiple cell types to minimize damage and initiate repair processes. In systemic sclerosis, these repair processes appear to run unchecked, leading to aberrant remodeling and fibrosis of the skin and multiple internal organs, yet the fundamental pathological defect remains unknown. We describe herein a transition wherein the abundant CD34(+) dermal fibroblasts present in healthy human skin disappear in the skin of systemic sclerosis patients, and CD34(-), podoplanin(+), and CD90(+) fibroblasts appear. This transition is limited to the upper dermis in several inflammatory skin diseases, yet in systemic sclerosis, it can occur in all regions of the dermis. In vitro, primary dermal fibroblasts readily express podoplanin in response to the inflammatory stimuli tumor necrosis factor and IL-1β. Furthermore, we show that on acute skin injury in both human and murine settings, this transition occurs quickly, consistent with a response to inflammatory signaling. Transitioned fibroblasts partially resemble the cells that form the reticular networks in organized lymphoid tissues, potentially linking two areas of fibroblast research. These results allow for the visualization and quantification of a basic stage of fibroblast differentiation in inflammatory and fibrotic diseases in the skin.

Tight Skin 2 Mice Exhibit Delayed Wound Healing Caused by Increased Elastic Fibers in Fibrotic Skin

Rationale: The Tight Skin 2 (Tsk2) mouse model of systemic sclerosis (SSc) has many features of human disease, including tight skin, excessive collagen deposition, alterations in the extracellular matrix (ECM), increased elastic fibers, and occurrence of antinuclear antibodies with age. A tight skin phenotype is observed by 2 weeks of age, but measurable skin fibrosis is only apparent at 10 weeks. We completed a series of wound healing experiments to determine how fibrosis affects wound healing in Tsk2/+ mice compared with their wild-type (WT) littermates. Method: We performed these experiments by introducing four 4 mm biopsy punched wounds on the back of each mouse, ventral of the midline, and observed wound healing over 10 days. Tsk2/+ mice showed significantly delayed wound healing and increased wound size compared with the WT littermates at both 5 and 10 weeks of age. We explored the potential sources of this response by wounding Tsk2/+ mice that were genetically deficient either for the NLRP3 inflammasome (a known fibrosis mediator), or for elastic fibers in the skin, using a fibulin-5 knockout. Conclusion: We found that the loss of elastic fibers restores normal wound healing in the Tsk2/+ mouse and that the loss of the NLRP3 inflammasome had no effect. We conclude that elastic fiber dysregulation is the primary cause of delayed wound healing in the Tsk2/+ mouse and therapies that promote collagen deposition in the tissue matrix in the absence of elastin deposition might be beneficial in promoting wound healing in SSc and other diseases.

FibronectinEDA promotes chronic cutaneous fibrosis through Toll-like receptor signaling

Scleroderma is a progressive autoimmune disease affecting multiple organs. Fibrosis, the hallmark of scleroderma, represents transformation of self-limited wound healing into a deregulated self-sustaining process. The factors responsible for maintaining persistent fibroblast activation in scleroderma and other conditions with chronic fibrosis are not well understood. Toll-like receptor 4 (TLR4) and its damage-associated endogenous ligands are implicated in immune and fibrotic responses. We now show that fibronectin extra domain A (Fn(EDA)) is an endogenous TLR4 ligand markedly elevated in the circulation and lesional skin biopsies from patients with scleroderma, as well as in mice with experimentally induced cutaneous fibrosis. Synthesis of Fn(EDA) was preferentially stimulated by transforming growth factor-β in normal fibroblasts and was constitutively up-regulated in scleroderma fibroblasts. Exogenous Fn(EDA) was a potent stimulus for collagen production, myofibroblast differentiation, and wound healing in vitro and increased the mechanical stiffness of human organotypic skin equivalents. Each of these profibrotic Fn(EDA) responses was abrogated by genetic, RNA interference, or pharmacological disruption of TLR4 signaling. Moreover, either genetic loss of Fn(EDA) or TLR4 blockade using a small molecule mitigated experimentally induced cutaneous fibrosis in mice. These observations implicate the Fn(EDA)-TLR4 axis in cutaneous fibrosis and suggest a paradigm in which aberrant Fn(EDA) accumulation in the fibrotic milieu drives sustained fibroblast activation via TLR4. This model explains how a damage-associated endogenous TLR4 ligand might contribute to converting self-limited tissue repair responses into intractable fibrogenesis in chronic conditions such as scleroderma. Disrupting sustained TLR4 signaling therefore represents a potential strategy for the treatment of fibrosis in scleroderma.

Enfuvirtide injection site reactions: a clinical and histopathological appraisal

BACKGROUND/OBJECTIVES

Enfuvirtide was the first of a new class of antiretroviral agents termed 'fusion inhibitors' used for the treatment of HIV-1 infection. Enfuvirtide is administered subcutaneously and injection site reactions (ISR) are commonplace (98%). The aim of this study was to analyse in detail the histopathological changes associated with striking ISR seen in four patients.

METHODS

Biopsies were obtained at various times post-injection and were reviewed histologically. The changes in epidermal, dermal and subcutaneous connective tissue and the presence and nature of the inflammatory cellular infiltrate were noted. An immunohistochemical assessment was undertaken.

RESULTS

All biopsy specimens demonstrated striking changes in the dermal connective tissue. Alteration in collagen was the most prominent feature and resembled a morphoea/scleroderma-like process. These changes persisted well beyond cessation of enfuvirtide (>1 year). The relative populations of dermal dendritic cells (DDC) (types 1 (Factor XIIIa) and 2 (CD34+)) were analysed and a reciprocal relationship between DDC subpopulations was observed akin to that observed in other sclerosing and fibrosing conditions.

CONCLUSION

This study details histopathological changes associated with enfuvirtide ISR. We postulate that changes in DDC populations may contribute to the pathogenesis of the sclerotic process observed with enfuvirtide ISR.