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.

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.

Assessing factors affecting sunscreen use and barriers to compliance: a cross-sectional survey-based study.

While sunscreen is effective prevention for skin cancer, public sunscreen use and compliance are low. Identifying factors affecting sunscreen use and barriers to compliance are important to understand in order to increase sunscreen use, especially among high-risk individuals. We conducted a single institution survey of 429 dermatology clinic patients to better understand patients' barriers to sunscreen use. Overall several personal barriers to sunscreen use included dislike of feel or appearance of sunscreen (33.7%) and time constraints (15.3%). The cost was a barrier to use in 16.4% of cases underscoring the importance for dermatologists to consider socioeconomic barriers to sunscreen use and provide cost-effective sun protection counseling to patients whenever possible. Dermatologists recommending sunscreen use was associated with a higher rate of use of sunscreen (p < .001) highlighting the important role of sun protective counseling by the dermatologist.

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.

Angioinvasive fungal infections impacting the skin: Diagnosis, management, and complications.

As discussed in the first article in this continuing medical education series, angioinvasive fungal infections pose a significant risk to immunocompromised and immunocompetent patients alike, with a potential for severe morbidity and high mortality. The first article in this series focused on the epidemiology and clinical presentation of these infections; this article discusses the diagnosis, management, and potential complications of these infections. The mainstay diagnostic tests (positive tissue culture with histologic confirmation) are often supplemented with serum biomarker assays and molecular testing (eg, quantitative polymerase chain reaction analysis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry) to ensure proper speciation. When an angioinvasive fungal infection is suspected or diagnosed, further workup for visceral involvement also is essential and may partially depend on the organism. Different fungal organisms have varied susceptibilities to antifungal agents, and knowledge on optimal treatment regimens is important to avoid the potential complications associated with undertreated or untreated fungal infections.

Angioinvasive fungal infections impacting the skin: Background, epidemiology, and clinical presentation.

Angioinvasive fungal infections cause significant morbidity and mortality because of their propensity to invade blood vessel walls, resulting in catastrophic tissue ischemia, infarct, and necrosis. While occasionally seen in immunocompetent hosts, opportunistic fungi are emerging in immunosuppressed hosts, including patients with hematologic malignancy, AIDS, organ transplant, and poorly controlled diabetes mellitus. The widespread use of antifungal prophylaxis has led to an "arms race" of emerging fungal resistance patterns. As the at-risk population expands and new antifungal resistance patterns develop, it is critical for dermatologists to understand and recognize angioinvasive fungal pathogens, because they are often the first to encounter the cutaneous manifestations of these diseases. Rapid clinical recognition, histopathologic, and culture confirmation can help render a timely, accurate diagnosis to ensure immediate medical and surgical intervention. Superficial dermatophyte infections and deep fungal infections, such as blastomycosis and histoplasmosis, have been well characterized within the dermatologic literature, and therefore this article will focus on the severe infections acquired by angioinvasive fungal species, including an update on new and emerging pathogens. In the first article in this continuing medical education series, we review the epidemiology and cutaneous manifestations. The second article in the series focuses on diagnosis, treatment, and complications of these infections.

A case of primary cutaneous Ewing sarcoma in a neutropenic patient.

Primary cutaneous Ewing sarcoma is a rare clinical presentation of Ewing sarcoma, usually occurring as a small, localized tumor on the extremities of young adults and associated with favorable prognosis. We report a case of primary cutaneous Ewing sarcoma, which presented on the sole of the foot of a 27-year-old patient with relapsed acute myeloid leukemia and neutropenia. Diagnosis was determined through histological features and staining, as well as fluorescence in situ hybridization and molecular testing. The patient underwent wide-local excision with plan to begin targeted chemotherapy, but unfortunately died from adenovirus pneumonia while neutropenic before targeted chemotherapy was initiated.