Current treatment options for acanthosis nigricans

Gender, racial, ethnic, and Fitzpatrick skin type representation in Acanthosis nigricans clinical trials

Acanthosis nigricans (AN) is characterized by dark, velvety patches and thin plaques primarily in the body folds. AN is more prevalent in skin of color populations, including Black/African American, Native American, and Hispanic patients. As the U.S. population becomes increasingly diverse, the need for inclusive dermatologic research becomes more pressing. Given the increased prevalence of AN in skin of color patients, there is a need to evaluate representation in AN clinical trials. This study aims to uncover gender, race, ethnicity, and Fitzpatrick skin type (FST) representation in AN clinical trials. A systematic literature search was performed across PubMed, Embase, and Cochrane databases to identify participant characteristics in clinical trials focused on AN treatment. Our review yielded 21 clinical trials, totaling 575 participants, with an identified predominance of female participants (69.0%) and a surprising absence of race or ethnicity data. Out of the 11 studies that included FST data, 1.2% of participants were type II, 20.6% were type III, 50.0% were type IV, and 28.2% were type V. None of the participants were FST I or VI. Herein, we highlight a predominate inclusion of female and FST III-V patients in AN clinical trials, the populations most impacted by this condition. We also highlight the need for improved race and ethnicity reporting and the importance of including all FSTs in clinical studies. Addressing this gap is critical for developing safe, efficacious, patient-centered, and equitable treatments for all AN patients. Future research should prioritize comprehensive inclusion of race, ethnicity, and the full spectrum of FSTs.

Comparison of efficacy and safety of tretinoin 0.05% and glycolic acid peeling 70% in axillary and neck lesions of acanthosis nigricans: A single-blinded, randomized trial

BACKGROUND

Acanthosis nigricans is a non-inflammatory skin pigmentary disorder characterized by a dark, velvety appearance, primarily observed in the neck and axillary areas. It is commonly associated with obesity, diabetes, and insulin resistance. Although the primary treatment is correcting the underlying disorders, many aesthetic modalities have been established to improve appearance owing to cosmetic concerns.

AIMS

We aimed to compare and investigate the effectiveness and side effects of tretinoin 0.05% and glycolic acid 70% in treating acanthosis nigricans lesions of the axillary and neck area.

METHODS

This single-blinded, randomized trial recruited patients with neck or axillary involvement. Each patient was randomized to use cream tretinoin 0.05% every other night on one side, while the other side was treated with glycolic acid 70%, which was applied every 2 weeks at the clinic for four consecutive sessions. The study duration was 8 weeks, and patients were evaluated every 2 weeks based on their response to treatment, satisfaction, and side effects.

RESULTS

Thirty patients, including 14 with neck lesions and 16 with axillary lesions, were included. Tretinoin was significantly more effective for axillary lesions in terms of treatment response and patient satisfaction (p = 0.02 and p = 0.008, respectively). It was also shown that as the severity of the lesions increased, the response to treatment and patient satisfaction decreased, specifically when treating axillary lesions with glycolic acid (p = 0.02 and p = 0.03, respectively).

CONCLUSION

Neither method was significantly effective for neck lesions. However, tretinoin 0.05% was shown to be more efficacious in treating axillary lesions of acanthosis nigricans, despite causing minimal side effects.

Review of facial acanthosis nigricans: Easy to diagnose and difficult to treat marker of hyperinsulinemia/metabolic syndrome

Facial acanthosis nigricans (FAN) is an increasingly discussed anatomical variation of acanthosis nigricans (AN). Its presentation as brown to black pigmentation with ill-defined blurred margins with varying degree of textural changes commonly over forehead, temporal, and malar regions of the face predominantly in dark-skinned individuals with a male predilection can be confused with other common facial melanoses. Its pathogenesis, clinical features, and management are in many ways similar to in the commonly described areas like neck and major flexural areas. Understanding of FAN has gained momentum in the past decade with studies highlighting its association with various metabolic abnormalities particularly insulin resistance and obesity. It is now being considered to be a cutaneous marker of metabolic syndrome. While there is uniformity in its clinical description, there appears to be scope for further in depth biochemical and histopathological studies to link the pigmentation, altered texture and microscopic changes in individuals presenting with FAN and hyperinsulinemia with or without other features of metabolic syndrome. It awaits a consensus on grading its severity and correlating it with histological features as patients often hesitate to be subjected to a biopsy of the face. This is a review of current literature pertaining to FAN. Newer clinical, dermoscopic, histopathological, and biochemical insights will help to understand this relatively new entity.

Efficacy of 15% trichloroacetic acid peel versus 35% glycolic acid peel in acanthosis Nigricans: A randomized open-label study

Introduction

Acanthosis Nigricans (AN) is an acquired disorder of keratinization. It presents as hyperpigmentation, velvety texture of skin that can involve any part of the body including the face. Different topical, systemic therapies, or physical therapies including laser have been explored. However, there are not many randomized controlled studies for the majority of therapy alternatives besides lifestyle modifications and weight reduction.

Objectives

The aim of this study was to compare the effectiveness of 15% trichloroacetic acid (TCA) and 35% glycolic acid (GA) peel for AN.

Materials and Methods

Forty participants were included and randomized into two groups. In groups A and B, peeling with 15% TCA and 35% GA was done, respectively. The effectiveness of each peel was assessed using changes in the Acanthosis Nigricans Area and Severity Index Score (ANASI) and Physician Assessment Score. Statistical analysis included Wilcoxon-Mann-Whitney test, Friedman test, and generalized estimating equations.

Results

The overall change in ANASI over time was compared in the two groups using the generalized estimating equations method. A significant difference was observed in the trend of ANASI over time between the two groups (P < 0.001). TCA peel group showed more change in ANASI as compared with GA peel group.

Conclusion

In our research, 15% TCA has a better efficacy when compared with 35% GA peel after three sessions of chemical peeling. We therefore recommend the use of 15% TCA peel in AN as a safe and effective treatment option. However, more comprehensive randomized control studies are required for supporting data.

Efficacy and safety of lasers versus topical medications for acanthosis nigricans and pseudo-acanthosis nigricans treatment: a systematic review

Acanthosis nigricans (AN) is a cutaneous disorder identified by well-defined pigmented plaques mostly detected on skin folds. Timely diagnosis and treatment of AN is essential as it could be an early manifestation of an underlying condition. The treatment of choice for AN has not been determined yet. Our study aimed to compare the efficacy and safety of various lasers with topical medications, including cream and peel. PubMed, Scopus, and Web of Science databases, as well as the Google Scholar search engine, were thoroughly searched until May 1st, 2023. Study selection was restricted to clinical trials published in English language comparing lasers with topical treatments. This study followed the PRISMA guidelines for systematic reviews and meta-analyses. Out of 1748 studies, Six clinical trials met our inclusion criteria, with 133 patients. We examined laser therapies, including fractional CO2 laser, 1550-nm erbium fiber laser, and long-pulsed alexandrite laser, while the topical treatments comprised glycolic acid (GA) peel, retinoic acid peel, trichloroacetic acid (TCA) peel, and tretinoin cream. In two studies, GA peel demonstrated favorable results compared to fractional CO2 laser. Besides, fractional CO2 laser exhibited efficacy, surpassing TCA peel in AN management. Additionally, a fractional 1550-nm erbium fiber laser displayed superiority over tretinoin cream in reducing average roughness. Similarly, a long-pulsed alexandrite laser demonstrated its effectiveness in axillary AN treatment compared to the combination of tretinoin and ammonium lactate. Overall, the findings revealed that laser therapy was associated with superior results. Moreover, topical treatments are safe and efficacious in AN management.

Correlation between Acanthosis Nigricans Scoring Chart (ANSC) and narrowband reflectance spectrophotometer in assessing severity of acanthosis nigricans

INTRODUCTION

There is a lack of standardized tool to monitor treatment outcome of acanthosis nigricans. To meet this end, we developed the Acanthosis Nigricans Scoring Chart (ANSC) that evaluates skin color (score range of 1-8) and skin texture (score range of 1-6), which adds up to a total ANSC score (score range of 2-14). We aimed to determine the correlation of ANSC to narrowband reflectance spectrophotometry and to evaluate its reliability.

METHODS

A cross-sectional study was conducted in adult acanthosis nigricans patients. Two raters independently graded participants using ANSC twice, in which scores were correlated to readings from Mexameter MX18. Intra- and interrater reliability were also evaluated via intraclass correlation coefficient (ICC).

RESULTS

Participants had mean (sd) melanin and erythema indices of 615.8 (176.2) and 451.4 (53.4), respectively. Mean (sd) total ANSC score was 9.43 (2.43). The total ANSC score and skin color subdomain demonstrated strong correlations (r > 0.6) with spectrophotometric results, whereas skin texture showed a moderate correlation (r = 0.4-0.6). Total ANSC score generally had excellent intra- and interrater reliabilities (ICC > 0.85).

CONCLUSION

The total ANSC score and its subdomains strongly correlate with spectrophotometer and demonstrate excellent reliability in assessing acanthosis nigricans.

Utilization of glucagon-like peptide-1 receptor agonists in children and adolescents in China: a real-world study

Background

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have been widely used in treating type 2 diabetes mellitus (T2DM) and obesity in adults, but scientific research about the indication in children and adolescents is scarce. The current study aims to explore the prescriptions of GLP-1RAs in children and adolescents in China and to evaluate its rationality.

Methods

GLP-1RA prescriptions of children and adolescents were retrospectively obtained from the Hospital Prescription Analysis Cooperative Project. The study extracted information on patient's demographic characteristics, monotherapy and combination therapy of GLP-1RAs, and trends in GLP-1RA usage from 2016 to 2021. The rationality of GLP-1RA prescriptions was comprehensively assessed based on the indications approved by China National Medical Products Administration (NMPA), the U.S. Food and Drug Administration (FDA), European Medicines Agency (EMA), Pharmaceuticals and Medical Devices Agency (PMDA), and published randomized controlled trials (RCTs).

Results

A total of 234 prescriptions from 46 hospitals were included, with a median age of 17 years old. The majority of patients were diagnosed with overweight/obesity or prediabetes/diabetes, accounting for 43.59% and 46.15%, respectively. There were 88 patients on GLP-1RA monotherapy. GLP-1RAs plus metformin was the most common combination therapy (38.89%). 12.39% of patients were found a co-administration with orlistat. The share of overweight/obesity prescriptions increased from 27% in 2016 to 54% in 2021, whereas prediabetes/diabetes prescriptions declined from 55% to 42%. The prescriptions were divided into appropriate and questionable groups according to the diagnosis, and the potentially questionable prescription was related to age (p = 0.017), department visited (p = 0.002), and any hospitalization (p < 0.001).

Conclusions

This study described the prescribing of GLP-1RAs in children and adolescents. Our findings indicated that the utilization of GLP-1RAs has increased from 2016 to 2021. There was a strong basis for administering GLP-1RAs in overweight/obesity and prediabetes/diabetes, whereas the evidence was insufficient in other conditions. It is crucial to demand robust and sustained efforts to enhance the awareness of the safety of utilization of GLP-1RAs in children and adolescents.

Efficacy of Fractional Carbon Dioxide (CO2) Laser versus Q-Switched Neodymium-Doped Yttrium Aluminum Garnet (Nd:YAG) and Potassium-Titanyl-Phosphate (KTP) Lasers in the Treatment of Acanthosis Nigricans

Background

Acanthosis nigricans (AN) is a common chronic skin disorder clinically presents by velvety hyperpigmented lesions mainly at the flexural areas. Fractional photothermolysis has been reported to improve both pigmentary and textural changes by removing thin layers of skin with minimal thermal damage. Other options are the Q-switched (Qs) Nd:YAG (1064 nm) and Qs KTP (532 nm) lasers. Both can induce collagen remodeling by dermal photo-mechanical microdamage.

Aim of the Work

The aim of this study was to assess the clinical efficacy and the safety of fractional CO₂ laser versus Qs Nd:YAG and KTP lasers in the treatment of acanthosis nigricans.

Methods

This randomized-controlled split neck study was conducted on 23 patients suffering from AN. For each patient, one side of the neck was randomly assigned to fractional CO₂ laser and the other side to Qs Nd:YAG and KTP lasers every four weeks for four months followed by 4 monthly follow-up assessment. Acanthosis Nigricans Area and Severity Index (ANASI) score, melanin and erythema indices as well as Patient Satisfaction Scale (PSS) were used to assess improvement on each side separately.

Results

There was no statistically significant difference regarding the clinical improvement between the side treated with Fractional CO₂ laser and the side treated with Qs Nd:YAG and KTP lasers (P value >0.05). In most patients, both sides showed improvement during different sessions of therapy, as regards ANASI scores, melanin indices, patient satisfaction scores, and side effects.

Conclusion

In this study, we concluded that both fractional CO₂ and Q-switched lasers proved to be a safe and effective line of treatment of acanthosis nigricans.

Acanthosis nigricans in the pediatric population: a narrative review of the current approach to management in primary care

Objective

This narrative review aims to provide readers with a comprehensive overview of the current literature of acanthosis nigricans (AN) in the pediatric and adolescent population, including best practices for identifying the condition, with a focus on the recommended management in the primary care setting to enable early and enhanced intervention.

Background

AN is frequently seen in obese and overweight children and adolescents. Current research suggests an association with insulin resistance, type 2 diabetes mellitus, and obesity, and often primary care physicians are the first point of contact for individuals with this dermatologic condition. However, identifying the condition at an early stage may be difficult.

Methods

We identified case and cross-sectional studies, clinical trials, and literature reviews of pediatric AN for ages 0 to 18 years in the United States and internationally. We considered publications for background from before the year 2000 and publications for approach to management from after the year 2000.

Conclusions

AN in the pediatric population can be a harbinger for underlying metabolic syndrome and insulin resistance. A thorough investigation and appropriate screening of children at risk, with a focus on early identification of the dermatologic condition and its associated comorbidities in the primary care setting, and early treatment is recommended to prevent long term consequences and decrease the risk of cardiovascular complications.

Comparing the efficacy and safety profiles of 0.025% and 0.05% tretinoin creams in treating acanthosis nigricans: a randomized double-blinded study

Acanthosis nigricans (AN) is a skin disorder with hyperpigmented and velvety plaques without a standardized treatment regimen. We aimed to compare the efficacy and safety profile of 0.025% and 0.05% tretinoin creams in managing AN. An 8-week, randomized double-blinded study was conducted in adults with AN. Participants were instructed to apply tretinoin cream on their posterior neck. Narrowband reflectance spectrophotometry was used to measure skin improvement through melanin (M) and erythema (E) indices at each follow-up visits at weeks 2, 4, and 8. Improvements in Acanthosis nigricans scoring chart (ANSC), investigator- and patient-global evaluation (IGE and PGE) and adverse cutaneous irritations were also scored. Both the 0.025% and 0.05% tretinoin creams were efficacious in acanthosis nigricans treatment with 17.1 ± 8.0% improvement and 18.4 ± 9.8% improvement after 8 weeks treatment by reflectance spectrophotometry measurement, respectively. There were generally no significant differences in efficacy, improvements in ANSC, IGE, and PGE scores, and local cutaneous irritations between the two groups. The 0.025% and 0.05% tretinoin demonstrate similar efficacy and safety profiles in the management of AN. Both concentrations are well tolerated with mild degree of local cutaneous irritation.

Metformina en el tratamiento de enfermedades dermatológicas: una revisión narrativa

Objetivo

Revisar y discutir la evidencia actual del uso de la metformina como herramienta terapéutica en enfermedades cutáneas.

Diseño

Artículo original. Investigación cualitativa. Revisión narrativa.

Emplazamiento

Aragón y Murcia, España.

Participantes

Médicos Internos Residentes de Dermatología Médico-Quirúrgica y Venereología y de Atención Primaria y Comunitaria.

Métodos

Se ha realizado una revisión narrativa utilizando la base de datos bibliográfica PubMed con fecha de búsqueda el 27 de enero de 2022.

Resultados

La metformina ha demostrado ser efectiva en el tratamiento de dermatosis inflamatorias tales como el acné, hidrosadenitis supurativa, psoriasis y dermatitis de contacto alérgica. También ha demostrado propiedades antitumorales frente al carcinoma basocelular, carcinoma espinocelular y melanoma. De forma adicional, se ha descrito efectos beneficiosos del tratamiento adyuvante con metformina en pacientes con carcinoma basocelular que reciben terapia fotodinámica. En pacientes con dermatosis relacionadas con endocrinopatías tales como el hirsutismo, la acantosis nigricans y los xantomas eruptivos, el tratamiento con metformina ha demostrado efectividad terapéutica. El tratamiento tópico con metformina ha demostrado ser eficaz en el tratamiento del melasma. Finalmente se ha propuesto como un fármaco con propiedades antienvejecimiento cutáneo y favorecedoras de la cicatrización. Para ninguna de las indicaciones previamente descritas se han objetivado efectos adversos graves.

Conclusiones

La metformina es un tratamiento efectivo y seguro en el esquema terapéutico de dermatosis inflamatorias, neoplasias cutáneas, dermatosis relacionadas con endocrinopatías, melasma, envejecimiento cutáneo y cicatrización.

Acanthosis Nigricans: An Updated Review

BACKGROUND

Early recognition of acanthosis nigricans is important because acanthosis nigricans can be a cutaneous manifestation of a variety of systemic disorders and, rarely, as a sign of internal malignancy.

OBJECTIVE

The purpose of this article is to familiarize pediatricians with the clinical manifestations, evaluation, diagnosis, and management of acanthosis nigricans.

METHODS

A search was conducted in November 2021in PubMed Clinical Queries using the key term "acanthosis nigricans". The search strategy included all clinical trials, observational studies, and reviews published within the past 10 years. Only papers published in the English literature were included in this review. The information retrieved from the above search was used in the compilation of the present article.

RESULTS

Acanthosis nigricans is characterized by symmetric, hyperpigmented, and velvety plaques with ill-defined borders, typically involving intertriginous areas. Obesity is the most common cause of acanthosis nigricans which is increasingly observed in obese children and adolescents and can serve as a cutaneous marker of insulin resistance. Early recognition of acanthosis nigricans is important because acanthosis nigricans can also be a cutaneous manifestation of a variety of systemic disorders and, rarely, as a sign of internal malignancy. This may consist of weight reduction, discontinuation of causative drugs, treatment of underlying endocrinopathy, or treatment of an underlying malignancy. For patients with isolated acanthosis nigricans and for those whose underlying cause is not amenable to treatment, treatment of the lesion may be considered for cosmetic reasons. Topical retinoids, vitamin D analogs, chemical peels, and other keratolytics are often used for the treatment of localized lesions. Seldom, systemic therapy such as oral retinoids may be considered for extensive or generalized acanthosis nigricans and acanthosis nigricans unresponsive to topical therapy. Other uncommon treatment modalities include dermabrasion, laser therapy, and surgical removal.

CONCLUSION

Although acanthosis nigricans is treatable, a complete cure is difficult to achieve. The underlying cause should be treated, if possible, to resolve and prevent the recurrence of acanthosis nigricans. The diagnosis is mainly clinical, based on the characteristic appearance (symmetrically distributed, hyperpigmented, velvety, papillomatous, hyperkeratotic plaques with ill-defined borders) and the typical sites (intertriginous areas, flexural area, and skin folds) of the lesions. The diagnosis might be difficult for lesions that have atypical morphology or are in an unusual location. Clinicians should be familiar with the clinical signs, evaluation, diagnosis, and therapy of acanthosis nigricans because of the link between it and underlying diseases.

Relationship between acanthosis nigricans, acrochordon and metabolic syndrome in patients with lichen planus

AIM

In the literature, there are no data examining the association with lichen planus with acanthosis nigricans and acrochordon, which are skin findings of metabolic syndrome (MS).

MATERIALS

A total of 108 lichen planus (LP) patients, age and sex-matched 109 controls, 217 patients in total were prospectively included in the study.

RESULTS

Metabolic Syndrome was found in 55 (50.9%) of 108 patients with lichen planus and 36.7% in the control group. The frequency of MS in the lichen planus group was found to be significantly higher than that in the control group (P = .03). The incidence of acanthosis nigricans (AN) was statistically higher in the LP group (P = .009). In addition, while 38 of 47 AN patients in the LP group had MS, 17 of 61 patients without AN had MS, and the presence of MS was found significantly higher in LP patients with AN (p˂0.001). The incidence of acrochordon was statistically higher in the LP group (P = .03). In addition, while 43 of 62 patients with acrochordon in the LP group had MS, 12 of 46 patients without acrochordon had MS, and the presence of MS was found significantly higher in patients with LP with acrochordon (P ˂ .001).

CONCLUSION

In our study, it was found that skin findings such as AN and acrochordon increased in patients with lichen planus. This increase was also observed in lichen planus patients with metabolic syndrome. Therefore, the association of acanthosis nigricans and acrochordon may be a predictive of metabolic syndrome in patients with lichen planus admitted to the dermatology outpatient clinic.

Comparative study between fractional carbon dioxide laser versus retinoic acid chemical peel in the treatment of acanthosis nigricans

BACKGROUND

Acanthosis nigricans (AN) is a common dermatological issue with several therapeutic modalities to treat. Despite retinoid is the first drug of choice in the treatment, the fractional-ablative carbon dioxide (CO₂ ) laser has revealed as a promising procedure for the management of neck-AN, outstanding to its ability for superficial ablation of the skin surface, with trans-epidermal melanin elimination.

OBJECTIVES

To decide whether fractional-ablative CO₂ laser or retinoic acid (5%) peel is the more effective and safe choice for AN treatment.

METHODS

In this study, twenty Egyptian cases with neck-AN were enrolled, where each case was exposed to four sessions with 2 weeks apart of both fractional CO₂  laser on the right half of the neck and retinoic acid peel on the left half of the neck. Cases were assessed by a scoring system: Acanthosis Nigricans Area and Severity Index (ANASI) score, two blinded dermatologists, and dermoscopically before and one month after treatment.

RESULTS

We found a highly statistically significant improvement among both treated groups regarding (ANASI) score and dermatologist's assessments. Bedside, the degree of sulci cutis, cristae cutis, brown-to-dark brown dots, and milia-like cysts, dermoscopic sign improvement was evident in both treated groups. However, fractional CO₂ laser shows the superior result to retinoic acid peel in the treatment.

CONCLUSION

Fractional CO₂ laser and retinoic acid peel are considered effective modalities for neck-AN treatment. However, fractional CO₂ laser was more effective.

Acanthosis nigricans: A review

BACKGROUND

Acanthosis nigricans (AN) is a cutaneous disorder characterized by symmetric velvety hyperpigmented plaques on intertriginous areas like axilla, neck, inframammary, and groin.

AIMS

To summarize the pathophysiology and classification of AN, provide an update of diagnostic testing strategies, and describe the current therapeutic options described so far in the literature for this disease.

METHODS

A comprehensive english language literature search across multiple databases (PubMed, EMBASE, MEDLINE, and Cochrane) for keywords (alone and in combination) was performed. MeSH as well as non-MeSH terms such as "acanthosis nigricans," "classification," "pathophysiology," "diagnosis," "treatment," "topical drugs," "systemic drugs," "chemical peeling," and "lasers" were taken into consideration.

RESULTS

The pathophysiology of AN revolves around a multifactorial stimulation of proliferation of epidermal keratinocytes and dermal fibroblasts. Various types of AN include benign, obesity-associated, syndromic, malignant, acral, unilateral, medication-induced, and mixed-type. Homeostasis model assessment-insulin resistance (HOMA-IR) is a good tool for assessment of insulin resistance. Management involves general measures (weight reduction and addressing the underlying cause, if any), topical drugs (retinoids, vitamin D analogs, and keratolytics), oral drugs (retinoids and insulin sensitizers), chemical peels (trichloroacetic acid), and lasers (Long pulsed alexandrite, fractional 1550-nm erbium fiber, and CO₂ ).

CONCLUSION

Acanthosis nigricans is a treatable condition; however, complete cure and disappearance of lesions are difficult to achieve. Weight reduction is the most scientific and practical management strategy. Long-term studies and further research is warranted in the pathophysiology and treatment of this common condition.

Malignant Acanthosis Nigricans with Recurrent Bladder Cancer: A Case Report and Review of Literature

Acanthosis nigricans (AN) is a rare cutaneous condition that may be a manifestation of certain endocrinological or autoimmune diseases, as well as a potential marker for underlying undiagnosed cancer. AN is classified as either benign or malignant based on its clinical associations. Malignant acanthosis nigricans (MAN), which tends to be extensive and develops rapidly, is considered to be a paraneoplastic syndrome associated with advanced cancer, commonly accompanied by intra-abdominal malignancies. Bladder cancer with AN concomitant with tripe palms (TP) and/or mucosal involvement is relatively rare and, to our knowledge, only seven cases of AN with bladder cancer have been reported in the English literature. However, to date, there have been no reports of bladder cancer with AN concomitant with TP, skin and mucosal involvement. Here, we present a case of a 71-year-old male diagnosed with AN coexisting with recurrent bladder cancer and simultaneous TP and oral AN. In addition, we provide a brief review of the available literature on this topic. Early recognition of skin features associated with internal malignancies provides an opportunity for early diagnosis, treatment of the internal malignancy and monitoring of tumor recurrence.

A Molecular Perspective on the Potential Benefits of Metformin for the Treatment of Inflammatory Skin Disorders

Due to its anti-hyperglycemic effect, metformin is the first-line medication for the treatment of type 2 diabetes, particularly in people who are obese. However, metformin is a drug with a very wide range of pharmacological properties and reports of its therapeutic effect on diseases including inflammation and cancer are increasing. Numerous research groups have reported that metformin has beneficial effects on a variety of inflammatory skin disorders including psoriasis, acanthosis nigricans, acne, hidradenitis suppurativa, and allergic contact dermatitis. According to these reports, in addition to the well-known action of metformin, that is, its anti-hyperglycemic effect, NF-kB inhibition and the resulting alteration to the cytokine network may be the potential targets of metformin. Its anti-hyperandrogenism effect has also been confirmed as the major action of metformin in some inflammatory skin diseases. Moreover, novel regulatory mechanisms, including autophagy and antioxidant processes, have been suggested as promising mechanisms of action for metformin in inflammatory skin disorders.

Nevoid acanthosis nigricans: Report of four cases localized to the umbilicus

Nevoid acanthosis nigricans is a rare, benign form of acanthosis nigricans. Of the 24 cases documented in the literature, only two are exclusively localized to the umbilicus. We present four cases of nevoid acanthosis nigricans localized to the umbilicus; in patients less than 25 years of age, with no known co-morbidities, three of whom were females. Two of the cases received, with good response, treatment based on topical calcipotriol, a medication not previously reported to be used for this indication. Contrary to other types of acanthosis nigricans, the nevoid acanthosis nigricans is not associated with any syndrome, endocrinopathy, obesity, medication, or neoplasia and it can be confused with other pathologies such as epidermal nevus or dermatosis neglecta.

The color of skin: black diseases of the skin, nails, and mucosa

Gradations in skin color are a consequence of differing amounts of melanin and their varying distribution. Although many darkly pigmented skin lesions are melanocytic and can be attributed to melanin content, the color of a black lesion can also be due to blood, necrotic tissue, or exogenous pigment. The source, pattern, and distribution of the color in black lesions usually offer important insight into its etiology. This contribution reviews conditions that can take on a black color, discussing the cause of the hue and any additional impact sun exposure may have.