Spatial characterization of interface dermatitis in cutaneous lupus reveals novel chemokine ligand-receptor pairs that drive disease.

Chemokines play critical roles in the recruitment and activation of immune cells in both homeostatic and pathologic conditions. Here, we examined chemokine ligand-receptor pairs to better understand the immunopathogenesis of cutaneous lupus erythematosus (CLE), a complex autoimmune connective tissue disorder. We used suction blister biopsies to measure cellular infiltrates with spectral flow cytometry in the interface dermatitis reaction, as well as 184 protein analytes in interstitial skin fluid using Olink targeted proteomics. Flow and Olink data concordantly demonstrated significant increases in T cells and antigen presenting cells (APCs). We also performed spatial transcriptomics and spatial proteomics of punch biopsies using digital spatial profiling (DSP) technology on CLE skin and healthy margin controls to examine discreet locations within the tissue. Spatial and Olink data confirmed elevation of interferon (IFN) and IFN-inducible CXCR3 chemokine ligands. Comparing involved versus uninvolved keratinocytes in CLE samples revealed upregulation of essential inflammatory response genes in areas near interface dermatitis, including AIM2. Our Olink data confirmed upregulation of Caspase 8, IL-18 which is the final product of AIM2 activation, and induced chemokines including CCL8 and CXCL6 in CLE lesional samples. Chemotaxis assays using PBMCs from healthy and CLE donors revealed that T cells are equally poised to respond to CXCR3 ligands, whereas CD14+CD16+ APC populations are more sensitive to CXCL6 via CXCR1 and CD14+ are more sensitive to CCL8 via CCR2. Taken together, our data map a pathway from keratinocyte injury to lymphocyte recruitment in CLE via AIM2-Casp8-IL-18-CXCL6/CXCR1 and CCL8/CCR2, and IFNG/IFNL1-CXCL9/CXCL11-CXCR3.

Atypical Chondroid Syringoma of the Toe.

Although chondroid syringoma rarely occurs outside the head and neck, the majority of malignant chondroid syringomas are identified in the extremities. Here, we present a case of atypical chondroid syringoma in the fifth toe. Diagnosis of chondroid syringoma with atypical cells was made following initial excisional biopsy and histology, necessitating repeated surgery for positive margins. In this case report, we examine the radiopathologic correlation of this diagnosis, detail the imaging findings of benign and malignant chondroid syringomas, and highlight how magnetic resonance imaging can be used to guide surgical planning and treatment course of this potentially malignant tumor.

CXCL9 Links Skin Inflammation and Fibrosis through CXCR3-Dependent Upregulation of Col1a1 in Fibroblasts.

Morphea is characterized by initial inflammation followed by fibrosis of the skin and soft tissue. Despite its substantial morbidity, the pathogenesis of morphea is poorly studied. Previous work showed that CXCR3 ligands CXCL9 and CXCL10 are highly upregulated in the sera and lesional skin of patients with morphea. We found that an early inflammatory subcutaneous bleomycin mouse model of dermal fibrosis mirrors the clinical, histological, and immune dysregulation observed in human morphea. We used this model to examine the role of the CXCR3 chemokine axis in the pathogenesis of cutaneous fibrosis. Using the REX3 (Reporting the Expression of CXCR3 ligands) mice, we characterized which cells produce CXCR3 ligands over time. We found that fibroblasts contribute the bulk of CXCL9-RFP and CXCL10-BFP by percentage, whereas macrophages produce high amounts on a per-cell basis. To determine whether these chemokines are mechanistically involved in pathogenesis, we treated Cxcl9-, Cxcl10-, or Cxcr3-deficient mice with bleomycin and found that fibrosis is dependent on CXCL9 and CXCR3. Addition of recombinant CXCL9 but not CXCL10 to cultured mouse fibroblasts induced Col1a1 mRNA expression, indicating that the chemokine itself contributes to fibrosis. Taken together, our studies provide evidence that CXCL9 and its receptor CXCR3 are functionally required for inflammatory fibrosis.

Gene Expression Profiling in the Skin Reveals Strong Similarities between Subacute and Chronic Cutaneous Lupus that Are Distinct from Lupus Nephritis.

Subacute cutaneous lupus erythematosus and chronic cutaneous lupus erythematosus are represented in the majority of cutaneous lupus subtypes, each of which has variable implications for systemic manifestations such as lupus nephritis. On dermatologic examination, subacute cutaneous lupus erythematosus and chronic cutaneous lupus erythematosus are distinct. However, it is often difficult to diagnose the subtype from histology alone. Our study utilized whole-genome microarray expression analysis on human skin samples of subacute cutaneous lupus erythematosus, on human skin samples of chronic cutaneous lupus erythematosus, and on healthy controls, along with analysis on human samples of lupus nephritis and normal kidney tissue to compare cutaneous lupus subtypes with each other as well as with lupus nephritis. The data revealed that cutaneous lupus subtypes were distinct from healthy control skin, with gene expression predominantly characterized by upregulation of IFN-1 and T-cell chemotactic genes. However, the cutaneous lupus subtypes were very similar to one another; comparative analyses revealed few statistically significant differences in gene expression. There were also distinct differences between the gene signatures of cutaneous lupus and lupus nephritis. Cutaneous lupus samples revealed gene signatures demonstrating a prominent inflammatory component that may suggest the skin as an early site of initiation of lupus pathogenesis, whereas lupus nephritis reflected the recruitment and activation of M2 macrophages and a wound healing signature.

Sweet syndrome with perifollicular involvement because of koebnerization from facial hair plucking.

Sweet syndrome (SS), also known as acute febrile neutrophilic dermatosis, is an uncommon skin eruption characterized by fever, leukocytosis, and tender erythematous papules, nodules, and plaques. Histopathologically, SS lesions are characterized by marked superficial papillary edema with a dense neutrophilic infiltrate. SS is known to demonstrate both the Koebner phenomenon and pathergy. The majority of reported cases of these phenomena occur following significant cutaneous injury (e.g., biopsies, burns) rather than minor trauma such as pressure and friction. Here, we present the first known reported case of SS koebnerization secondary to minor grooming-related hair plucking. In addition, this is also the first reported case to our knowledge of SS with perifollicular involvement on histopathology.

Employing immunohistochemical staining to labial minor salivary gland biopsies from patients with Sjogren's syndrome increases diagnostic certainty.

BACKGROUND: Sjogren's syndrome (SjS) is an autoimmune disease characterized clinically by dry eyes and dry mouth, and histopathologically by lymphocytic infiltrates in the salivary glands. Labial minor salivary gland biopsy (MSGB) is a major diagnostic test for SjS, deemed positive by a focus score of ≥1, meaning that ≥50 lymphocytes were found in 4 mm2 tissue on hematoxylin and eosin (H&E)-stained slides. The diagnosis can be challenging, and the above diagnostic criteria has low and variable sensitivity. METHODS: We performed a retrospective study on MSGBs done for possible SjS. We compared the percent of MSGBs which met the histologic criteria by H&E stain alone and that with the addition of CD45, CD3, and CD20 immunohistochemical (IHC) staining for these patients. A total of 45 cases with complete data were analyzed. RESULTS: Thirty-five of the 45 patients had the diagnosis of Sjogren's syndrome (SjS+) based on ACR criteria. However, based on H&E staining alone, only 22/35 cases (63%) met the histologic criteria. After adding IHC staining with CD45, CD3, and CD20 to MSGBs of SjS + patients, 29/35 (83%) cases met the histological criteria for SjS. All MSGBs from patients without SjS had no significant lymphocyte infiltrate on either H&E or IHC stains. CONCLUSIONS: Immunohistochemical better identifies lymphocytic infiltrates in MSGB and increases diagnostic certainty. Due to high cost, their use should be restricted to cases where there is high clinical suspicion of SjS and negative H&E evaluation alone, or if the diagnosis is uncertain.

Defining the Histologic Support Structures of the Nasal Ala and Soft Triangle: Toward Understanding the Cause of Iatrogenic Alar Retraction.

BACKGROUND: As rhinoplasty techniques have evolved to more extensive dissections, the incidence of iatrogenic deformities, such as alar rim retraction, has risen. Its mechanism is presently unknown. This study examined the microscopic anatomy of the nasal ala to define architectural support elements at the histologic level to determine why rhinoplasty dissection creates such deformities. METHODS: Eight cadaveric noses were harvested and sectioned through the soft triangle and ala. Various tissue stains were performed. Slides were examined using light microscopy. Anatomical features pertaining to cartilage, skin, mucosa, elastic fibers, and muscle were documented. RESULTS: Four male and four female noses were sectioned. The median cadaver age was 64 years (range, 47 to 83 years). On Elastica van Gieson stain, distinct elastic fibers span from the vestibular lining to the caudal margin of the lower lateral cartilage, and from the caudal edge of the lower lateral cartilage to the external alar skin. In the nasal ala midsection, trichrome stains reveal that skeletal muscle is located far beyond the lower lateral cartilage, close to the free alar margin. The soft triangle shows a distinct microanatomical structure, with heavy longitudinal condensations of elastin. These histologic findings have not been previously reported. CONCLUSIONS: A distinct anatomical alar wall endoskeleton has been identified. It is obligatorily disrupted by specific rhinoplasty maneuvers when dissection is carried out over the lateral crura and into areas without cartilaginous support. This microanatomy may explain factors that contribute to postoperative alar wall retraction. Leaving this area undisturbed or performing adjunctive measures with rhinoplasty can provide structural support to the external valves, thus minimizing the risk of deformity.

Verruciform xanthoma in recessive dystrophic epidermolysis bullosa and keratitis-ichthyosis-deafness syndrome: Report of two cases and a review of the literature.

Verruciform xanthoma is a benign, wart-like lesion that can clinically mimic squamous cell carcinoma. We describe two teenage patients with severe genodermatoses, recessive dystrophic epidermolysis bullosa (RDEB), and keratitis-ichthyosis-deafness (KID) syndrome, respectively, each found to have plaques suspicious for malignancy, later demonstrated on histopathologic examination to be verruciform xanthoma. We discuss the connection between these severe genodermatoses and the suspected pathophysiology of verruciform xanthoma. In addition, we highlight the importance of recognizing verruciform xanthoma as a clinical mimicker of squamous cell carcinoma, for which patients with RDEB and KID syndrome are at increased risk.

YAP/TAZ Activation Drives Uveal Melanoma Initiation and Progression.

Uveal melanoma (UM), the most common ocular malignancy, is characterized by GNAQ/11 mutations. Hippo/YAP and Ras/mitogen-activated protein kinase (MAPK) emerge as two important signaling pathways downstream of G protein alpha subunits of the Q class (GαQ/11)-mediated transformation, although whether and how they contribute to UM genesis in vivo remain unclear. Here, we adapt an adeno-associated virus (AAV)-based ocular injection method to directly deliver Cre recombinase into the mouse uveal tract and demonstrate that Lats1/2 kinases suppress UM formation specifically in uveal melanocytes. We find that genetic activation of YAP, but not Kras, is sufficient to initiate UM. We show that YAP/TAZ activation induced by Lats1/2 deletion cooperates with Kras to promote UM progression via downstream transcriptional reinforcement. Furthermore, dual inhibition of YAP/TAZ and Ras/MAPK synergizes to suppress oncogenic growth of human UM cells. Our data highlight the functional significance of Lats-YAP/TAZ in UM initiation and progression in vivo and suggest combination inhibition of YAP/TAZ and Ras/MAPK as a new therapeutic strategy for UM.

Expression of TLE1 in Malignant Melanoma With Spindle Cell Morphology: A Potential Diagnostic Pitfall.

OBJECTIVES: Transducer-like enhancer of split 1 (TLE1) immunohistochemistry is widely used as a biomarker of synovial sarcoma. Spindle cell or desmoplastic melanoma can morphologically mimic synovial sarcoma. The aim of this study was to investigate the expression of TLE1 in melanomas with a spindle cell morphology. METHODS: A search of the surgical pathology files resulted in 57 cases of melanomas diagnosed with a spindle cell or desmoplastic component. After review, 8 cases had no definitive dermal spindle cell component and 7 cases had insufficient tissue remaining and were excluded from the study. A total of 42 melanomas were examined for TLE1 immunohistochemistry using a mouse monoclonal antibody (Cell Marque, clone 1F5). Strength and percentage of nuclear TLE1 positivity was graded on a scale from 0 to 3+. Staining for TLE1 was considered positive for 2 to 3+ and negative for 0 to 1+. RESULTS: Nuclear TLE1 expression was identified in 24 (57%) of the 42 melanoma cases with spindle cell morphology (2+, n = 14; 3+, n = 10). TLE1 was considered negative in 18 cases (43%), of which most contained weak staining (1+, n = 14 [33%]) and only a small subset did not show any staining (0, n = 4 [10%]). CONCLUSION: TLE1 frequently highlights melanomas with spindle cell morphology and is a potential diagnostic pitfall. Therefore, when evaluating spindle cell tumors in which the differential may include both a melanoma and synovial sarcoma, TLE1 expression should be interpreted with caution and in conjunction with an immunohistochemical panel.

Concordance of somatic mutation profiles (BRAF,NRAS, and TERT) and tumoral PD-L1 in matched primary cutaneous and metastatic melanoma samples.

Despite the efficacy of BRAF-targeted and PD-L1-related immune therapies in tackling metastatic melanoma, a significant number of patients exhibit resistance. Given this, the objective of the current study was to ascertain concordance of somatic mutations in BRAF/NRAS/TERT and immunohistochemical PD-L1 and CD8 in matched primary cutaneous and metastatic melanoma. A total of 43 archival paired samples with sufficient material for genetic and immunohistochemical analyses met the criteria for inclusion in the study. Immunohistochemistry was performed for PD-L1 and CD8 and direct-DNA Sanger sequencing for BRAF/NRAS/TERT promoter mutational analyses. Agreement between paired samples was assessed using Cohen κ. Poor concordance among primary and corresponding metastases was noted in BRAF (9/42 cases discordant, κ = 0.49; 95% confidence interval [CI], 0.21-0.77; P = .0013), TERT promoter mutations (13/41 cases discordant, κ = 0.33; 95% CI, 0.04-0.62; P = .033), tumoral PD-L1 immunoexpression (9/43 cases discordant, κ = 0.39; 95% CI, 0.07-0.72; P = .0099), and immunoexpression of CD8+ T lymphocytes (12/43 cases discordant, κ = 0.44; 95% CI, 0.19-0.69; P = .002). Although NRAS1 and NRAS2 were highly concordant (42/43 and 39/43 cases, respectively), discordant NRAS2 mutational status was associated with a median time to metastasis of 90 versus 455 days for pairs with concordant status (P = .07). Although limited by sample size, our findings suggest that consideration be given to mutational analysis of metastatic tissue rather than the primary to guide BRAF-targeted therapy and question the roles of TERT promoter mutations and PD-L1 as predictive biomarkers in malignant melanoma.

Fas ligand promotes an inducible TLR-dependent model of cutaneous lupus-like inflammation.

Toll-like receptors TLR7 and TLR9 are both implicated in the activation of autoreactive B cells and other cell types associated with systemic lupus erythematosus (SLE) pathogenesis. However, Tlr9-/- autoimmune-prone strains paradoxically develop more severe disease. We have now leveraged the negative regulatory role of TLR9 to develop an inducible rapid-onset murine model of systemic autoimmunity that depends on T cell detection of a membrane-bound OVA fusion protein expressed by MHC class II+ cells, expression of TLR7, expression of the type I IFN receptor, and loss of expression of TLR9. These mice are distinguished by a high frequency of OVA-specific Tbet+, IFN-γ+, and FasL-expressing Th1 cells as well as autoantibody-producing B cells. Unexpectedly, contrary to what occurs in most models of SLE, they also developed skin lesions that are very similar to those of human cutaneous lupus erythematosus (CLE) as far as clinical appearance, histological changes, and gene expression. FasL was a key effector mechanism in the skin, as the transfer of FasL-deficient DO11gld T cells completely failed to elicit overt skin lesions. FasL was also upregulated in human CLE biopsies. Overall, our model provides a relevant system for exploring the pathophysiology of CLE as well as the negative regulatory role of TLR9.

Distinguishing between irritated seborrheic keratosis and squamous cell carcinoma in situ using BCL-2 and IMP3 immunohistochemistry.

BACKGROUND: Distinguishing an irritated seborrheic keratosis (ISK) from a squamous cell carcinoma in situ (SCCIS) can occasionally be challenging, both histologically and clinically. The purpose of this study was to determine if an immunohistochemical profile of select markers can aid in differentiating these two entities. METHODS: We randomly selected and stained 103 ISK and 111 SCCIS for EGFR, IMP3, and BCL-2. IMP3 staining was scored as negative or 0 (0% positive), 1+ (1%-25% positive), 2+ (26%-50% positive), and 3+ (>50% positive). BCL-2 and EGFR were graded as either positive or negative. RESULTS: Sixty five out of 103 (63%) ISKs were positive for BCL-2, none (0%) were positive for IMP3, and 18 (18%) were positive for EGFR. Fifteen out of 111 (14%) SCCISs were positive for BCL-2, 26 (23%) were positive for IMP3, and 27 (24%) were positive for EGFR. BCL-2 was moderately sensitive (63%) and specific (87%) in identifying ISK. IMP3 was specific (100%) but not sensitive (23%) for SCCIS. CONCLUSION: Our findings indicate that the combination of IMP3 and BCL-2 may be of diagnostic utility in distinguishing between ISK and SCCIS in daily clinical practice. EGFR immunohistochemistry did not appear to be useful in this setting.