Update on nail unit histopathology.

Histopathologic evaluation of the nail unit is an essential component in the diagnosis of nail unit disorders. This review highlights recent updates in nail unit histopathology and discusses literature covering a wide range of nail disorders including melanoma/melanocytic lesions, squamous cell carcinoma, onychomatricoma, onychopapilloma, onychomycosis, lichen planus, and other inflammatory conditions. Herein we also discuss recent literature on nail clipping histopathology, a useful and noninvasive diagnostic tool that continues to grow in popularity and importance to both dermatologists and dermatopathologists.

A call for nail clipping histopathology to become an essential component of the routine evaluation of melanonychia: Benefitting patients as a triage and surgical planning maneuver.

We call on dermatologists and dermatopathologists to include nail clipping histopathology as an essential component of the routine evaluation of melanonychia. This manuscript demonstrates a case where an adult woman with broad melanonychia of the right thumbnail declined a nail matrix biopsy, but was amenable to a nail clipping.The nail clipping showed pigmentation, melanocyte remnants, and small cavities in the nail plate. These features have been published previously by our group as a clue to nail unit melanoma within nail clippings.This patient was rapidly triaged for nail matrix biopsy, which demonstrated nail unit melanoma in situ. Every patient with melanonychia can benefit from a nail clipping by examination of the location of the pigmentation within the nail plate for surgical planning, and if melanocyte remnants are detected, the nail clipping also serves as a rapid triage mechanism for nail matrix biopsy to evaluate for nail unit melanoma. Fontana-stained sections will highlight the pigmentation in the nail plate, and its location in the nail plate can easily be described by the dermatopathologist. Nail clippings performed in the setting of clinically apparent melanonychia may show helpful histopathologic findings of pigmented fungi, hemorrhage, external pigmentation, features of other pigmented nail unit tumors, as well as other entities. Nail clipping histopathology can provide extensive information in the evaluation of melanonychia with minimal discomfort for a patient, and little disruption to a physician's clinic flow. With this additional case of a nail unit melanoma diagnosed after initial concern found in a nail clipping, as well as other information in the literature, it is clear that melanocyte remnants found in nail clippings are reliable concerning features related to nail unit melanoma in adults. With knowledge of these histopathologic features in nail clippings and the significance of melanocyte remnants, the dermatopathologist can play a crucial role in the use of a nail clipping as a life-saving diagnostic maneuver. Accordingly, given the potential benefit to patients in this setting, as well as other uses of a nail clipping in the evaluation of melanonychia, we call on dermatologists and dermatopathologists to innovate the routine evaluation of melanonychia through the routine employment of nail clippings for histopathologic evaluation.

Impact of trends in new and emerging contact allergens.

Allergic contact dermatitis represents a T cell-mediated, delayed-type hypersensitivity response to exogenous agents. While allergic contact dermatitis is one of the most common causes of skin disease encountered by dermatologists, emerging trends within the field are in constant flux, as influenced by ever-changing industry practices and evolving consumer behaviors. Although certain allergens continue to predominate, new chemicals are frequently being introduced, thus shifting the pattern of allergen exposure and sensitization. This review examines the impact of trends in new and emerging contact allergens, with particular attention to clinical contexts in which these agents may be encountered. In addition, we offer a working knowledge of these allergens' characteristics, sources, and relevance, while outlining recommendations to accurately evaluate, diagnose, and provide appropriate counseling for these diseases.

Incidence and Prevalence of Granuloma Annulare in the United States.

IMPORTANCE: Although several single-center studies have estimated that granuloma annulare may account for approximately 0.1% to 0.4% of new patients presenting to dermatologists, large-scale population-based studies estimating the prevalence and incidence of granuloma annulare are lacking. OBJECTIVES: To estimate the population-based incidence and prevalence of granuloma annulare in the United States and to identify the most commonly prescribed treatments. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study used deidentified data from the Optum Clinformatics Data Mart Database from January 1, 2017, to December 31, 2018, to identify patients with granuloma annulare. MAIN OUTCOMES AND MEASURES: After validating an approach to classify patients with granuloma annulare using International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes, the primary outcomes were age-, sex-, and race/ethnicity-specific annualized incidence and prevalence estimates for granuloma annulare. In addition, treatment use within 6 to 12 months after the first diagnosis of granuloma annulare was examined. Confidence intervals for prevalence and incidence estimates were computed assuming a binomial distribution using the Wilson score method. Age-, sex-, and race/ethnicity-specific incidence and prevalence estimates were compared using the χ2 test. RESULTS: A total of 11 608 patients with incident granuloma annulare (8680 female patients [74.8%]; mean [SD] age, 56.5 [18.8] years) and 17 862 patients with prevalent granuloma annulare (13 548 female patients [75.8%]; mean [SD] age, 56.6 [18.5] years) were identified during the study period. The overall annualized incidence of granuloma annulare was 0.04%, or 37.9 (95% CI, 36.9-38.9) per 100 000, and the overall annualized prevalence of granuloma annulare was 0.06%, or 58.3 (95% CI, 57.1-59.5) per 100 000. The incidence and prevalence of granuloma annulare were highest in the fifth decade of life. The incidence and prevalence of granuloma annulare were higher among women (incidence: female to male ratio, 2.8:1; prevalence: female to male ratio, 3.0:1). Within 6 months of their first diagnosis, 4822 patients (41.5%) filled a prescription for a topical corticosteroid, and 1087 patients (9.4%) received an intralesional injection. Within 6 months of their first diagnosis, oral tetracycline prescriptions were filled by 820 patients (7.1%), and hydroxychloroquine prescriptions were filled by 268 patients (2.3%). CONCLUSIONS AND RELEVANCE: Granuloma annulare is a rare disease in the United States that is more common among women and middle-aged to older individuals. The findings of this cross-sectional study provide important background regarding the basic epidemiology and overall burden of granuloma annulare in the United States. Future studies are needed to better understand the association of granuloma annulare with quality of life and the most optimal treatment approaches for this condition.

Association of Granuloma Annulare With Type 2 Diabetes, Hyperlipidemia, Autoimmune Disorders, and Hematologic Malignant Neoplasms.

IMPORTANCE: Although granuloma annulare (GA) has been associated with several other conditions, these studies have been limited by single-center designs and small sample sizes. OBJECTIVE: To evaluate whether there is an association between GA and type 2 diabetes, hyperlipidemia, autoimmune conditions, and hematologic malignant neoplasms, using a large population-based cohort study. DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort study conducted between January 1, 2016, and June 30, 2019, used deidentified data from the US Optum Clinformatics Data Mart Database. A total of 5137 patients with GA were matched by age and sex with up to 10 randomly selected controls (n = 51 169) with a diagnosis of a nevus or seborrheic keratosis. MAIN OUTCOMES AND MEASURES: Logistic regression was used to evaluate for potential associations between GA and diabetes, hyperlipidemia, autoimmune conditions, and hematologic malignant neoplasms. All analyses were adjusted for race/ethnicity, income, and educational level. RESULTS: This study included 5137 individuals with GA (3760 women [73.2%]; mean [SD] age, 57.7 [19.0] years) and 51 169 controls (37 456 women [73.2%]; mean [SD] age, 57.7 [19.0] years). Those with GA were more likely than controls to have baseline diabetes (1086 [21.1%] vs 6780 [13.3%]; adjusted odds ratio [aOR], 1.67; 95% CI, 1.55-1.80), hyperlipidemia (1669 [32.5%] vs 14 553 [28.4%]; aOR, 1.15; 95% CI, 1.08-1.23), hypothyroidism (727 [14.2%] vs 5780 [11.3%]; aOR, 1.24; 95% CI, 1.15-1.36), and rheumatoid arthritis (62 [1.2%] vs 441 [0.9%]; aOR, 1.34; 95% CI, 1.02-1.75). Those with GA were more likely to have incident diabetes (144 [2.8%] vs 1061 [2.1%]; aOR, 1.31; 95% CI, 1.10-1.57), hypothyroidism (41 [0.8%] vs 252 [0.5%]; aOR, 1.59; 95% CI, 1.14-2.22), systemic lupus erythematosus (21 [0.4%] vs 65 [0.1%]; aOR, 3.06; 95% CI, 1.86-5.01), and rheumatoid arthritis (26 [0.5%] vs 122 [0.2%]; aOR, 2.05; 95% CI, 1.34-3.13). There was no association between GA and an increased risk of hematologic malignant neoplasms. CONCLUSIONS AND RELEVANCE: This population-based cohort study identified associations between GA and baseline diabetes and hyperlipidemia as well as between GA and both baseline and incident autoimmune conditions. These findings suggest that diabetes and hyperlipidemia may be risk factors for the development of GA and that autoimmunity may be an important factor in the pathogenesis of GA.

Wax models in dermatology: Updated through 2020.

Wax models have occupied a unique position in the teaching of dermatology. The wax model offers a unique presentation of the morphology, often not captured by other methods. Much has already been written about the unfortunate fate of many of these collections. Some models went to historical collections, a few were saved to continue their didactic purpose, and still others met their untimely demise. There has been renewed interest in the preservation of these models in recent years, from dermatologists and historians alike, and this has led to increasing efforts to document the origin, migration, exhibition, and maintenance of these collections. Our mission for this study is to report on our findings of the existence and whereabouts of dermatologic wax models since the 1990 survey. Even with the advent of the Internet and interest generated for preserving these wonderful illustrations of dermatologic conditions, many collections have remained unknown or dismantled. In the end, wax models have survived the introduction of hand-colored artist's renditions, color photography, and even computerized illustrations. Although no longer the premier teaching tool of yesteryear, their survival reflects upon the development of dermatology and the initial transition from hand-colored prints to our current digital-oriented age.

A retrospective review of cutaneous lymphoma in Botswana.

BACKGROUND: Primary cutaneous lymphoma (PCL) represents a heterogeneous collection of non-Hodgkin lymphomas originating in the skin. Our study describes the clinical and histological findings of cutaneous lymphoma within Botswana to expand the paucity of data on this rare disease in sub-Saharan Africa. METHODS: We conducted a retrospective review from the dermatology clinic at Princess Marina Hospital (Gaborone, Botswana) of patients evaluated by skin biopsy for cutaneous lymphoma between 2008 and 2017. Patients with initial diagnostic suspicion for cutaneous lymphoma had biopsies re-reviewed by experienced dermatopathologists and were given a final diagnosis of either (i) cutaneous lymphoma, (ii) atypical lymphocytic infiltrate (ALI), or (iii) a reactive cutaneous process. RESULTS: Thirty-eight cases were identified with a mean age of 50.0 years and a male:female (M:F) ratio of 13:6. Final diagnoses included: 27 cases of cutaneous lymphoma, eight cases of ALI, and three cases of reactive cutaneous processes. Subtypes of cutaneous lymphoma diagnosed included: mycosis fungoides (MF) (81.5%), plasmablastic lymphoma (7.4%), Epstein-Barr virus-positive T-cell lymphoma (3.7%), subcutaneous panniculitis-like T-cell lymphoma (3.7%), and peripheral T-cell lymphoma, not otherwise specified (3.7%). The most common immunohistochemical staining profile in MF cases was CD8 predominance over CD4. CONCLUSIONS: Primary cutaneous lymphoma causes significant morbidity and mortality globally. Given the limited resources in sub-Saharan Africa, it is essential to educate providers on the manifestations and histology of PCL. This study is an important step towards understanding the demographics, clinical presentation, histologic features, and mortality of patients diagnosed with PCL in Botswana and similar low-resource settings.

Dermatology-Driven Quality Improvement Interventions to Decrease Diagnostic Delays for Kaposi Sarcoma in Botswana.

PURPOSE: Kaposi sarcoma (KS) is an HIV-associated skin cancer that is highly prevalent in Botswana and associated with significant morbidity and mortality. Histopathology-confirmed diagnosis is required for chemotherapeutic interventions in Botswana, which creates barriers to care because of limited biopsy and pathology services. We sought to understand the role a dermatology specialist can play in improving KS care through quality improvement (QI) initiatives to reduce histologic turnaround times (TATs) for KS. METHODS: Employment of a dermatology specialist within a public health care system that previously lacked a local dermatologist generated quality improvements in KS care. Retrospective review identified patients diagnosed with KS by skin biopsy in the predermatology QI interval (January 1, 2015, to December 31, 2015) versus the postdermatology QI interval (January 1, 2016, to November 31, 2017). Histology TATs and clinical characteristics were recorded. A t test compared the median histology TATs in the pre- and post-QI intervals. RESULTS: A total of 192 cases of KS were diagnosed by skin biopsy. Nearly all (98.4%) were HIV-positive; and 52.8% of patients were male with a median age of 39 years. Median TAT in the postdermatology QI interval was 11 days (interquartile range, 12-23 days) compared with 32 days in the predermatology QI interval (interquartile range, 24-56 days; P < .00). CONCLUSION: Dermatology-led QI initiatives to improve multispecialty care coordination can significantly decrease histology TATs for KS. The reduction of diagnostic delays is a key first step to decreasing the morbidity and mortality associated with this cancer in resource-limited settings.

Immunostaining for High-Risk Human Papillomavirus in Condyloma Lesions in Immunocompromised Patients.

BACKGROUND: Human papillomavirus (HPV) is the underlying infectious cause of condyloma acuminata (CA) and high-risk types of HPV can cause cancer. Condyloma may undergo malignant degeneration, particularly in immunosuppressed patients. The presence of high-risk HPV in CA is a risk factor for developing malignancy; however, determining which patients with condyloma are clinically at risk can be difficult. High-risk HPV can now be localized within CA using routine immunohistochemical stains. METHODS: We examined HPV (cocktail, 16, 18) immunohistochemical staining of CA and the relevant clinical history from immunocompromised patients and compared them with age- and sex- matched immunocompetent patients with biopsied CA. RESULTS: HPV was detected in 9 of the 12 specimens from immunocompromised patients (75%), and 6 of the 12 specimens from the age- and sex-matched comparison patients (50%). HPV-16 was detected in 7 of the 12 specimens from immunocompromised patients (58%), and 4 of the 12 specimens from comparison patients (33%). HPV-18 was not detected in any of the 21 specimens from immunocompromised or comparison patients for which the stain was available. CONCLUSION: High-risk HPV is found within CA lesions, more often in immunocompromised patients, and confirming the presence of these HPV types with stains in high-risk patient populations may help guide the clinician in treatment and surveillance in certain cases.

High frequency ultrasound: a novel instrument to quantify granuloma burden in cutaneous sarcoidosis.

BACKGROUND: As is the case for many skin diseases, cutaneous sarcoidosis does not currently have an objective measure of disease burden to establish disease severity and response to treatment. The disease has traditionally been assessed by visual skin changes, including induration and erythema; however, such assessments may fail to quantify the total skin granuloma burden, as the majority of the granulomatous inflammation may lie deep within the dermis and not be reliably detected by sight or palpation. OBJECTIVES: The purpose of this pilot study is to evaluate the feasibility of high frequency ultrasound as an objective measure of granuloma burden in cutaneous sarcoidosis and to compare high frequency ultrasound to a previously validated clinical instrument (CSAMI) and histopathology evaluation. RESULTS: A strong correlation was observed between the mean brightness of high frequency ultrasound images and both the lesional CSAMI score (Spearman's rho: 0.9710, p = 0.0012) and percent of dermis with granulomas histopathology (Spearman's rho: 0.8407 p = 0.0361). CONCLUSIONS: These results confirm high frequency ultrasound is a valid, objective measure of granuloma burden in cutaneous sarcoidosis and represents a novel, non-invasive measure of disease severity that correlates to the previously validated CSAMI clinical severity score and histopathology evaluation.