Validation of the Delphi Consensus Diagnostic Criteria for Necrobiotic Xanthogranuloma.

This diagnostic study validates the Delphi consensus diagnostic criteria for necrobiotic xanthogranuloma compared with its mimics.

Spatial transcriptomics reveals organized and distinct immune activation in cutaneous granulomatous disorders.

BACKGROUND: Noninfectious (inflammatory) cutaneous granulomatous disorders include cutaneous sarcoidosis (CS), granuloma annulare (GA), necrobiosis lipoidica (NL), and necrobiotic xanthogranuloma (NXG). These disorders share macrophage-predominant inflammation histologically, but the inflammatory architecture and the pattern of extracellular matrix alteration varies. The underlying molecular explanations for these differences remain unclear. OBJECTIVE: We sought to understand spatial gene expression characteristics in these disorders. METHODS: We performed spatial transcriptomics in cases of CS, GA, NL, and NXG to compare patterns of immune activation and other molecular features in a spatially resolved fashion. RESULTS: CS is characterized by a polarized, spatially organized type 1-predominant response with classical macrophage activation. GA is characterized by a mixed but spatially organized pattern of type 1 and type 2 polarization with both classical and alternative macrophage activation. NL showed concomitant activation of type 1, type 2, and type 3 immunity with a mixed pattern of macrophage activation. Activation of type 1 immunity was shared among, CS, GA, and NL and included upregulation of IL-32. NXG showed upregulation of CXCR4-CXCL12/14 chemokine signaling and exaggerated alternative macrophage polarization. Histologic alteration of extracellular matrix correlated with hypoxia and glycolysis programs and type 2 immune activation. CONCLUSIONS: Inflammatory cutaneous granulomatous disorders show distinct and spatially organized immune activation that correlate with hallmark histologic changes.

Defining D-irAEs: consensus-based disease definitions for the diagnosis of dermatologic adverse events from immune checkpoint inhibitor therapy.

With an increasing number of patients eligible for immune checkpoint inhibitors, the incidence of immune-related adverse events (irAEs) is on the rise. Dermatologic immune-related adverse events (D-irAEs) are the most common and earliest to manifest, often with important downstream consequences for the patient. Current guidelines lack clarity in terms of diagnostic criteria for D-irAEs. The goal of this project is to better define D-irAE for the purposes of identification, diagnosis, and future study of this important group of diseases.The objectives of this project were to develop consensus guidance for an approach to D-irAEs including disease definitions and severity grading. Knowing that consensus among oncologists, dermatologists, and irAE subspecialists would be critical for usability, we formed a Dermatologic irAE Disease Definition Panel. The panel was composed of 34 experts, including oncologists, dermatologists, a rheumatologist, and an allergist/immunologist from 22 institutions across the USA and internationally. A modified Delphi consensus process was used, with two rounds of anonymous ratings by panelists and two virtual meetings to discuss areas of controversy. Panelists rated content for usability, appropriateness, and accuracy on 9-point scales in electronic surveys and provided free text comments. A working group aggregated survey responses and incorporated them into revised definitions. Consensus was based on numeric ratings using the RAND/UCLA Appropriateness Method with prespecified definitions.Following revisions based on panelist feedback, all items received consensus in the second round of ratings. Consensus definitions were achieved for 10 core D-irAE diagnoses: ICI-vitiligo, ICI-lichen planus, ICI-psoriasis, ICI-exanthem, ICI-bullous pemphigoid, ICI-Grover's, ICI-eczematous, ICI-eruptive atypical squamous proliferation, ICI-pruritus without rash, and ICI-erosive mucocutaneous. A standard evaluation for D-irAE was also found to reach consensus, with disease-specific exceptions detailed when necessary. Each disorder's description includes further details on disease subtypes, symptoms, supportive exam findings, and three levels of diagnostic certainty (definite, probable, and possible).These consensus-driven disease definitions standardize D-irAE classification in a useable framework for multiple disciplines and will be the foundation for future work. Given consensus on their accuracy and usability from a representative panel group, we anticipate that they can be used broadly across clinical and research settings.

Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms. Part II diagnosis and management.

Drug-induced hypersensitivity syndrome, also known as drug reaction with eosinophilia and systemic symptoms, is a severe cutaneous adverse reaction characterized by an exanthem, fever, and hematologic and visceral organ involvement. The differential diagnosis includes other cutaneous adverse reactions, infections, inflammatory and autoimmune diseases, and neoplastic disorders. Three sets of diagnostic criteria have been proposed; however, consensus is lacking. The cornerstone of management is immediate discontinuation of the suspected drug culprit. Systemic corticosteroids remain first-line therapy, but the literature on steroid-sparing agents is expanding. Longitudinal evaluation for sequelae is recommended. Adjunctive tests for risk stratification and drug culprit identification remain under investigation. Part II of this continuing medical education activity begins by exploring the differential diagnosis and diagnosis of drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms and concludes with an evidence-based overview of evaluation and treatment.

Identification of a neutrophil-specific PIK3R1 mutation facilitates targeted treatment in a patient with Sweet syndrome.

BackgroundAcute febrile neutrophilic dermatosis (Sweet syndrome) is a potentially fatal multiorgan inflammatory disease characterized by fever, leukocytosis, and a rash with a neutrophilic infiltrate. The disease pathophysiology remains elusive, and current dogma suggests that Sweet syndrome is a process of reactivity to an unknown antigen. Corticosteroids and steroid-sparing agents remain frontline therapies, but refractory cases pose a clinical challenge.MethodsA 51-year-old woman with multiorgan Sweet syndrome developed serious corticosteroid-related side effects and was refractory to steroid-sparing agents. Blood counts, liver enzymes, and skin histopathology supported the diagnosis. Whole-genome sequencing, transcriptomic profiling, and cellular assays of the patient's skin and neutrophils were performed.ResultsWe identified elevated IL-1 signaling in lesional Sweet syndrome skin caused by a PIK3R1 gain-of-function mutation specifically found in neutrophils. This mutation increased neutrophil migration toward IL-1ß and neutrophil respiratory burst. Targeted treatment of the patient with an IL-1 receptor 1 antagonist resulted in a dramatic therapeutic response and enabled a tapering off of corticosteroids.ConclusionDysregulated PI3K/AKT signaling is the first signaling pathway linked to Sweet syndrome and suggests that this syndrome may be caused by acquired mutations that modulate neutrophil function. Moreover, integration of molecular data across multiple levels identified a distinct subtype within a heterogeneous disease that resulted in a rational and successful clinical intervention. Future patients will benefit from efforts to identify potential mutations. The ability to directly interrogate the diseased skin allows this method to be generalizable to other inflammatory diseases and demonstrates a potential personalized medicine approach for patients with clinically challenging disease.Funding SourcesBerstein Foundation, NIH, Veterans Affairs (VA) Administration, Moseley Foundation, and H.T. Leung Foundation.

Stenotrophomonas maltophilia, a Pathogen of Increasing Relevance to Dermatologists: A Case Report and Review of the Literature.

Stenotrophomonas maltophilia is a Gram-negative bacillus that causes skin and soft tissue infections (SSTI), as well as bacteremia, pneumonia, and urinary tract infections. S. maltophilia infections are typically nosocomial and are often transmitted through water sources. Although historically described in immunocompromised hosts, S. maltophilia prevalence is increasing in both immunocompromised and immunocompetent populations. In light of high morbidity and mortality, it is critical that dermatologists are aware of this organism because of the limited options for therapy. Here, we describe a case of a S. maltophilia abscess with bacteremia in a patient with chronic lymphocytic leukemia and aplastic anemia that was successfully treated with trimethoprim-sulfamethoxazole. We also review the current standard of care and propose an algorithm for the treatment of S. maltophilia infection.

Risk Factors for the Development of Bullous Pemphigoid in US Patients Receiving Immune Checkpoint Inhibitors.

Importance: De novo bullous pemphigoid (BP) is a rare immune-mediated adverse event from immune checkpoint inhibitors (ICIs) that can necessitate permanent discontinuation of the anticancer therapy, but the risk factors for developing this toxic effect are unknown. Objective: To compare potential risk factors for BP in patients treated with ICIs who did and did not develop BP. Design, Setting, and Participants: This cohort and nested propensity score-matched case-control study was conducted at the Dana-Farber Cancer Institute, Brigham and Women's Hospital, and Massachusetts General Hospital. All patients at these facilities with de novo BP after ICI treatment were compared with all patients on the cancer registry who were treated with ICIs between October 1, 2014, and December 31, 2020. Patients with incomplete or blinded data regarding the ICI agent or total cycles were excluded. Exposures: In the cohort, assessed potential risk factors included age at ICI introduction, sex, ICI molecular target, and cancer type, which were then used as matching variables. In the propensity score-matched case-control analysis, risk factors assessed included sex, race and ethnicity, cancer stage, metastasis sites, idiopathic BP comorbidities, pre-ICI vaccination, radiation history, body mass index, and derived neutrophil-to-lymphocyte ratio. Main Outcomes and Measures: Diagnosis of BP at any point after ICI treatment, confirmed by direct immunofluorescence, indirect immunofluorescence, autoantibody serologies, or diagnostic consensus among study board-certified dermatologists. Odds ratios (ORs) and 95% CIs were calculated for all risk factors. In the secondary analysis, best overall responses to ICIs between cases and controls were compared by Fisher exact test. Results: Among 5636 patients treated with ICIs at Dana-Farber Cancer Institute, Brigham and Women's Hospital, and Massachusetts General Hospital during the study period, 35 (0.6%; median [IQR] age, 72.8 [13.4] years; 71.4% [25] male patients) developed BP. In a multivariate logistic regression model that assessed 2955 patients with complete data in the cancer registry, age 70 years or older (OR, 2.32; 95% CI, 1.19-4.59; P = .01), having melanoma (OR, 3.21; 95% CI, 1.51-6.58; P < .003), and having nonmelanoma skin cancer (OR, 8.32; 95% CI, 2.81-21.13; P < .001) were significantly associated with developing BP. In the nested 1:2 case-control comparison of all 35 cases to 70 propensity score-matched controls, a complete or partial response on initial restaging imaging was a risk factor for BP development (OR, 3.37; 95% CI, 1.35-9.30; P = .01). Bullous pemphigoid cases also more frequently exhibited overall tumor response to ICIs than matched controls (29 of 35 [82.9%] vs 43 of 70 [61.4%]; P = .03). Conclusions and Relevance: In this cohort study, age 70 years or older and skin cancer were associated with increased risk of developing ICI-associated BP. Given the association of BP with improved initial and best overall tumor responses, early identification and toxic effect-directed treatment should be prioritized, especially in individuals at risk for developing de novo BP.

Neutrophilic Dermatoses: a Clinical Update.

Purpose of Review: Neutrophilic dermatoses are defined by the presence of a sterile neutrophilic infiltrate on histopathology. This review focuses on the pathogenesis, epidemiology, clinicopathological features, diagnosis, and management of four disorders: Sweet syndrome, pyoderma gangrenosum, Behçet syndrome, and neutrophilic eccrine hidradenitis. Recent Findings: Recent studies have provided insight into the complex pathogenesis of neutrophilic dermatoses. Evidence supports an intricate interplay of abnormal neutrophil function and inflammasome activation, malignant transformation into dermal infiltrating neutrophils, and genetic predisposition. Summary: Neutrophilic dermatoses have diverse cutaneous and extracutaneous manifestations and may be associated with significant morbidity and mortality. Common underlying associations include infectious, inflammatory, and neoplastic disorders, as well as drug reactions. Emerging diagnostic and therapeutic frameworks identify an expanding role for biologic and targeted anti-inflammatory therapies.

Patient Perspectives on the Use of Artificial Intelligence for Skin Cancer Screening: A Qualitative Study.

Importance: The use of artificial intelligence (AI) is expanding throughout the field of medicine. In dermatology, researchers are evaluating the potential for direct-to-patient and clinician decision-support AI tools to classify skin lesions. Although AI is poised to change how patients engage in health care, patient perspectives remain poorly understood. Objective: To explore how patients conceptualize AI and perceive the use of AI for skin cancer screening. Design, Setting, and Participants: A qualitative study using a grounded theory approach to semistructured interview analysis was conducted in general dermatology clinics at the Brigham and Women's Hospital and melanoma clinics at the Dana-Farber Cancer Institute. Forty-eight patients were enrolled. Each interview was independently coded by 2 researchers with interrater reliability measurement; reconciled codes were used to assess code frequency. The study was conducted from May 6 to July 8, 2019. Main Outcomes and Measures: Artificial intelligence concept, perceived benefits and risks of AI, strengths and weaknesses of AI, AI implementation, response to conflict between human and AI clinical decision-making, and recommendation for or against AI. Results: Of 48 patients enrolled, 26 participants (54%) were women; mean (SD) age was 53.3 (21.7) years. Sixteen patients (33%) had a history of melanoma, 16 patients (33%) had a history of nonmelanoma skin cancer only, and 16 patients (33%) had no history of skin cancer. Twenty-four patients were interviewed about a direct-to-patient AI tool and 24 patients were interviewed about a clinician decision-support AI tool. Interrater reliability ratings for the 2 coding teams were κ = 0.94 and κ = 0.89. Patients primarily conceptualized AI in terms of cognition. Increased diagnostic speed (29 participants [60%]) and health care access (29 [60%]) were the most commonly perceived benefits of AI for skin cancer screening; increased patient anxiety was the most commonly perceived risk (19 [40%]). Patients perceived both more accurate diagnosis (33 [69%]) and less accurate diagnosis (41 [85%]) to be the greatest strength and weakness of AI, respectively. The dominant theme that emerged was the importance of symbiosis between humans and AI (45 [94%]). Seeking biopsy was the most common response to conflict between human and AI clinical decision-making (32 [67%]). Overall, 36 patients (75%) would recommend AI to family members and friends. Conclusions and Relevance: In this qualitative study, patients appeared to be receptive to the use of AI for skin cancer screening if implemented in a manner that preserves the integrity of the human physician-patient relationship.

A Multicenter Cross-Sectional Study and Systematic Review of Necrobiotic Xanthogranuloma With Proposed Diagnostic Criteria.

Importance: Necrobiotic xanthogranuloma (NXG) is a non-Langerhans cell histiocytosis classically associated with paraproteinemia attributable to plasma-cell dyscrasias or lymphoproliferative disorders. Despite the morbidity of NXG, the literature is limited to case reports and small studies, and diagnostic criteria are lacking. Objective: To evaluate the characteristics of NXG and propose diagnostic criteria. Design, Setting, and Participants: This multicenter cross-sectional study was conducted at tertiary academic referral centers and followed by a systematic review and a consensus exercise. The multicenter cohort included patients with NXG diagnosed at the Brigham and Women's and Massachusetts General Hospitals (2000-2018), the University of Iowa Hospitals and Clinics (2000-2018), and the University of Pennsylvania Health System (2008-2018). The systematic review was conducted in 2018 and included patients with NXG identified in the Cochrane, Ovid EMBASE, PubMed, and Web of Science databases. The consensus exercise was conducted by 8 board-certified dermatologists to identify diagnostic criteria. Main Outcomes and Measures: Demographic factors, comorbidities, clinical features, and treatment response. Results: Of 235 included patients with NXG (34 from the multicenter cohort and 201 from the systematic review results), the mean (SD) age at presentation was 61.6 (14.2) years; 147 (62.6%) were female. Paraproteinemia was detected in 193 patients (82.1%), most often IgG-κ (117 patients [50.0%]). A malignant condition was detected in 59 patients (25.1%), most often multiple myeloma (33 patients [14.0%]). The overall rate of paraproteinemia and/or a malignant condition was 83.8% (197 patients). In the multicenter cohort, evolution of paraproteinemia into multiple myeloma was observed up to 5.7 years (median [range], 2.4 [0.1-5.7] years) after NXG presentation. Cutaneous lesions consisted of papules, plaques, and/or nodules, typically yellow or orange in color (113 of 187 [60.4%]) with a periorbital distribution (130 of 219 [59.3%]). The eye was the leading site of extracutaneous involvement (34 of 235 [14.5%]). In the multicenter cohort, intravenous immunoglobulin had the best treatment response rate (9 of 9 patients [100%]), followed by antimalarial drugs (4 of 5 patients [80%]), intralesional triamcinolone (6 of 8 patients [75%]), surgery (3 of 4 patients [75%]), chemotherapy (8 of 12 patients [67%]), and lenalidomide or thalidomide (5 of 8 patients [63%]). The consensus exercise yielded 2 major criteria, which were (1) clinical and (2) histopathological features consistent with NXG, and 2 minor criteria, consisting of (1) paraproteinemia, plasma-cell dyscrasia, and/or other associated lymphoproliferative disorder and (2) periorbital distribution of cutaneous lesions. In the absence of foreign body, infection, or another identifiable cause, fulfillment of both major and at least 1 minor criterion were proposed to establish the diagnosis of NXG. Conclusions and Relevance: Necrobiotic xanthogranuloma is a multisystem disorder associated with paraproteinemia and malignant conditions. The proposed diagnostic criteria may advance clinical research and should be validated.

Clinical Features and Comorbidities of Patients With Necrobiosis Lipoidica With or Without Diabetes.

Importance: Necrobiosis lipoidica (NL) is a rare granulomatous condition. Current knowledge of its key features is based on a limited number of studies and case reports, leading to wide variability in the characterization of its defining features, with limited comparison of patients with or without diabetes. Objective: To evaluate the epidemiologic characteristics, clinical features, and disease associations of NL in patients with or without type 1 or 2 diabetes. Design, Setting, and Participants: This multicenter retrospective review included 236 patients aged 15 to 84 years who were evaluated and received a diagnosis of NL at the University of Pennsylvania Health System between January 1, 2008, and July 15, 2018; University of Iowa Hospitals and Clinics between January 1, 2000, and June 15, 2018; and Brigham and Women's Hospital and Massachusetts General Hospital between January 1, 2000, and February 15, 2018. Main Outcomes and Measures: Patient demographics, clinical features, medical comorbidities, and biopsy status. Results: Of the 236 patients with NL, 200 were women and 36 were men, and 182 were white, with a median age at presentation of 50.0 years (interquartile range, 33.0-59.0 years). The diagnosis was biopsy proven in 156 patients (66.1%). Of the 230 patients with location specified, 225 (97.8%) had NL on the lower legs. A total of 138 patients with NL (58.5%; 95% CI, 52.7%-65.3%) had diabetes. The median hemoglobin A1c for patients with diabetes was 8.00% (interquartile range, 6.68%-9.50%) (to convert hemoglobin A1c to proportion of total hemoglobin, multiply by 0.01). Patients with diabetes were significantly younger than patients without diabetes (median age, 45.0 vs 52.0 years; P = .005), and slightly less likely to be female (112 of 138 [81.2%] vs 87 of 96 [90.6%]; P = .046), but lesion characteristics were otherwise comparable. Other notable comorbidities included obesity in 95 of 184 patients (51.6%; 95% CI, 44.4%-58.9%), hypertension in 104 of 230 patients (45.2%), dyslipidemia in 98 of 225 patients (43.6%), and thyroid disease in 56 of 229 patients (24.5%). Conclusions and Relevance: This study of NL supports its associations with diabetes as well as obesity, hypertension, dyslipidemia, and thyroid disease. Younger age and female sex were observed more frequently in patients with diabetes. Otherwise, NL lesions in patients with or without diabetes shared many clinical features, suggesting that risk factors outside of elevated blood glucose may play an important role in the disease. Future studies should evaluate these associations with the goal of further elucidating NL's underlying pathophysiologic characteristics.

Neutrophilic dermatoses: Pathogenesis, Sweet syndrome, neutrophilic eccrine hidradenitis, and Behçet disease.

Neutrophilic dermatoses are a heterogeneous group of inflammatory skin disorders that present with unique clinical features but are unified by the presence of a sterile, predominantly neutrophilic infiltrate on histopathology. The morphology of cutaneous lesions associated with these disorders is heterogeneous, which renders diagnosis challenging. Moreover, a thorough evaluation is required to exclude diseases that mimic these disorders and to diagnose potential associated infectious, inflammatory, and neoplastic processes. While some neutrophilic dermatoses may resolve spontaneously, most require treatment to achieve remission. Delays in diagnosis and treatment can lead to significant patient morbidity and even mortality. Therapeutic modalities range from systemic corticosteroids to novel biologic agents, and the treatment literature is rapidly expanding. The first article in this continuing medical education series explores the pathogenesis of neutrophilic dermatoses and reviews the epidemiology, clinical and histopathologic features, diagnosis, and management of Sweet syndrome, neutrophilic eccrine hidradenitis, and Behçet disease.