Analysis of recurrence patterns in acral versus nonacral melanoma: should histologic subtype influence treatment guidelines?

Establishment of a CD8+ T cells-related prognostic risk model for acral melanoma based on single-cell and bulk RNA sequencing

BACKGROUND

CD8+ T cells have been recognized as crucial factors in the prognosis of melanoma. However, there is currently a lack of gene markers that accurately describe their characteristics and functions in acral melanoma (AM), which hinders the development of personalized medicine.

METHODS

Firstly, we explored the composition differences of immune cells in AM using single-cell RNA sequencing (scRNA-seq) data and comprehensively characterized the immune microenvironment of AM in terms of composition, developmental differentiation, function, and cell communication. Subsequently, we constructed and validated a prognostic risk scoring model based on differentially expressed genes (DEGs) of CD8+ T cells using the TCGA-SKCM cohort through Lasso-Cox method. Lastly, immunofluorescence staining was performed to validate the expression of four genes (ISG20, CCL4, LPAR6, DDIT3) in AM and healthy skin tissues as included in the prognostic model.

RESULTS

The scRNA-seq data revealed that memory CD8+ T cells accounted for the highest proportion in the immune microenvironment of AM, reaching 70.5%. Cell-cell communication analysis showed extensive communication relationships among effector CD8+ T cells. Subsequently, we constructed a prognostic scoring model based on DEGs derived from CD8+ T cell sources. Four CD8+ T cell-related genes were included in the construction and validation of the prognostic model. Additionally, immunofluorescence results demonstrated that ISG20 and CCL4 were downregulated, while LPAR6 and DDIT3 were upregulated in AM tissues compared to normal skin tissues.

CONCLUSION

Identifying biomarkers based on the expression levels of CD8+ T cell-related genes may be an effective approach for establishing prognostic models in AM patients. The independently prognostic risk evaluation model we constructed provides new insights and theoretical support for immunotherapy in AM.

The genetic evolution of acral melanoma

Acral melanoma is an aggressive type of melanoma with unknown origins. It is the most common type of melanoma in individuals with dark skin and is notoriously challenging to treat. We examine exome sequencing data of 139 tissue samples, spanning different progression stages, from 37 patients. We find that 78.4% of the melanomas display clustered copy number transitions with focal amplifications, recurring predominantly on chromosomes 5, 11, 12, and 22. These complex genomic aberrations are typically shared across all progression stages of individual patients. TERT activating alterations also arise early, whereas MAP-kinase pathway mutations appear later, an inverted order compared to the canonical evolution. The punctuated formation of complex aberrations and early TERT activation suggest a unique mutational mechanism that initiates acral melanoma. The marked intratumoral heterogeneity, especially concerning MAP-kinase pathway mutations, may partly explain the limited success of therapies for this melanoma subtype.

Clinical Characteristics and Special Considerations in the Management of Rare Melanoma Subtypes

Rare histologic subtypes of melanoma, including acral, mucosal, uveal, and desmoplastic melanomas, only make up 5% of all diagnosed melanomas and are often underrepresented in large, randomized trials. Recent advancements in systemic therapy have shown marked improvement in pathologic response rates, improving progression-free and overall survival among cutaneous melanoma patients, but there are limited data to demonstrate improved survival among rarer subtypes of melanoma. Acral melanoma has a poor response to immunotherapy and is associated with worse survival. Mucosal melanoma has a large variability in its presentation, a poor prognosis, and a low mutational burden. Uveal melanoma is associated with a high rate of liver metastasis; recent adoption of infusion and perfusion therapies has demonstrated improved survival among these patients. Desmoplastic melanoma, a high-risk cutaneous melanoma, is associated with high locoregional recurrence rates and mutational burden, suggesting this melanoma may have enhanced response to immunotherapy. While these variants of melanoma represent distinct disease entities, this review highlights the clinicopathologic characteristics and treatment recommendations for each of these rare melanomas and highlights the utility of modern therapies for each of them.

Pattern Analysis of Benign and Malignant Atypical Melanocytic Skin Lesions of Palms and Soles: Variations of Dermoscopic Features According to Anatomic Site and Personal Experience

Background: The differential diagnosis of atypical melanocytic skin lesions localized on palms and soles represents a diagnostic challenge: indeed, this spectrum encompasses atypical nevi (AN) and early-stage melanomas (EN) displaying overlapping clinical and dermoscopic features. This often generates unnecessary excisions or delayed diagnosis. Investigations to date were mostly carried out in specific populations, focusing either on acrolentiginous melanomas or morphologically typical acquired nevi. Aims: To investigate the dermoscopic features of atypical melanocytic palmoplantar skin lesions (aMPPLs) as evaluated by variously skilled dermatologists and assess their concordance; to investigate the variations in dermoscopic appearance according to precise location on palms and soles; to detect the features with the strongest association with malignancy/benignity in each specific site. Methods: A dataset of 471 aMPPLs-excised in the suspect of malignancy-was collected from 10 European Centers, including a standardized dermoscopic picture (17×) and lesion/patient metadata. An anatomical classification into 17 subareas was considered, along with an anatomo-functional classification considering pressure/friction, (4 macroareas). A total of 156 participants (95 with less than 5 years of experience in dermoscopy and 61 with ≥than 5 years) from 17 countries performed a blinded tele-dermoscopic pattern analysis over 20 cases through a specifically realized web platform. Results: A total of 37,440 dermoscopic evaluations were obtained over 94 (20%) EM and 377 (80%) AN. The areas with the highest density of EM compared to AN were the heel (40.3% EM/aMPPLs) of the sole and the "fingers area" (33%EM/aMPPLs) of the palm, both characterized by intense/chronic traumatism/friction. Globally, the recognition rates of 12 dermoscopic patterns were non statistically different between 95 dermatology residents and 61 specialists: aMPPLs in the plantar arch appeared to be the most "difficult" to diagnose, the parallel ridge pattern was poorly recognized and irregular/regular fibrillar patterns often misinterpreted. Regarding the aMPPL of the "heel area", the parallel furrow pattern (p = 0.014) and lattice-like pattern (p = 0.001) significantly discriminated benign cases, while asymmetry of colors (p = 0.002) and regression structures (p = 0.025) malignant ones. In aMPPLs of the "plantar arch", the lattice-like pattern (p = 0.012) was significant for benignity and asymmetry of structures, asymmetry of colors, regression structures, or blue-white veil for malignancy. In palmar lesions, no data were significant in the discrimination between malignant and benign aMPPLs. Conclusions: This study highlights that (i) the pattern analysis of aMPPLs is challenging for both experienced and novice dermoscopists; (ii) the histological distribution varies according to the anatomo-functional classification; and (iii) different dermoscopic patterns are able to discriminate malignant from benign aMPPLs within specific plantar and palmar areas.

Nuclear Localization of Yes-Associated Protein Is Associated With Tumor Progression in Cutaneous Melanoma

Yes-associated protein (YAP), an effector molecule of the Hippo signaling pathway, is expressed at high levels in cutaneous melanoma. However, the role of YAP in melanoma progression according to cellular localization is poorly understood. Tissues from 140 patients with invasive melanoma were evaluated by immunohistochemistry. Flow cytometry, western blotting, viability assays, wound healing assays, verteporfin treatment, and xenograft assays were conducted using melanoma cell lines B16F1 and B16F10 subjected to YapS127A transfection and siYap knockdown. Nuclear YAP localization was identified in 63 tumors (45.0%) and was more frequent than cytoplasmic YAP in acral lentiginous and nodular subtypes (P = .007). Compared with cytoplasmic YAP melanomas, melanomas with nuclear YAP had higher mitotic activity (P = .016), deeper invasion (P < .001), and more frequently metastasized to lymph nodes (P < .001) and distant organs (P < .001). Patients with nuclear YAP melanomas had poorer disease-free survival (P < .001) and overall survival (P < .001). Nuclear YAP was an independent risk factor for distant metastasis (hazard ratio: 3.206; 95% CI, 1.032-9.961; P = .044). Proliferative ability was decreased in siYapB16F1 (P < .001) and siYapB16F10 (P = .001) cells and increased in YapS127AB16F1 (P = .003) and YapS127AB16F10 (P = .002) cells. Cell cycle analysis demonstrated relative G1 retention in siYapB16F1 (P < .001) and siYapB16F10 (P < .001) cells and S retention in YapS127AB16F1 cells (P = .008). Wound healing assays showed that Yap knockdown inhibited cell invasion (siYapB16F1, P = .001; siYapB16F10, P < .001), whereas nuclear YAP promoted it (YapS127AB16F, P < .001; YapS127AB16F1, P = .017). Verteporfin, a direct YAP inhibitor, reduced cellular proliferation in B16F1 (P = .003) and B16F10 (P < .001) cells. Proliferative effects of nuclear YAP were confirmed in xenograft mice (P < .001). In conclusion, nuclear YAP in human melanomas showed subtype specificity and correlated with proliferative activity and proinvasiveness. It is expected that YAP becomes a useful prognostic marker, and its inhibition may be a potential therapy for melanoma patients.

A European Multicentric Investigation of Atypical Melanocytic Skin Lesions of Palms and Soles: The iDScore-PalmoPlantar Database

Background: The differential diagnosis of atypical melanocytic palmoplantar skin lesions (aMPLs) represents a diagnostic challenge, including atypical nevi (AN) and early melanomas (MMs) that display overlapping clinical and dermoscopic features. We aimed to set up a multicentric dataset of aMPL dermoscopic cases paired with multiple anamnestic risk factors and demographic and morphologic data. Methods: Each aMPL case was paired with a dermoscopic and clinical picture and a series of lesion-related data (maximum diameter value; location on the palm/sole in 17 areas; histologic diagnosis; and patient-related data (age, sex, family history of melanoma/sunburns, phototype, pheomelanin, eye/hair color, multiple/dysplastic body nevi, and traumatism on palms/soles). Results: A total of 542 aMPL cases-113 MM and 429 AN-were collected from 195 males and 347 females. No sex prevalence was found for melanomas, while women were found to have relatively more nevi. Melanomas were prevalent on the heel, plantar arch, and fingers in patients aged 65.3 on average, with an average diameter of 17 mm. Atypical nevi were prevalent on the plantar arch and palmar area of patients aged 41.33 on average, with an average diameter of 7 mm. Conclusions: Keeping in mind the risk profile of an aMPL patient can help obtain a timely differentiation between malignant/benign cases, thus avoiding delayed and inappropriate excision, respectively, with the latter often causing discomfort/dysfunctional scarring, especially at acral sites.

Recent advancements in the diagnosis and treatment of acral melanoma

Acral melanoma (AM) is the most common histologic subtype of melanoma in dark-skinned patients and is associated with a worse prognosis and a high mortality rate, largely due to the inconspicuous nature of early-stage lesions, which can lead to late diagnosis. Because of the overlapping clinical and histopathological features of AM with other forms of cutaneous melanomas, early detection of AM requires a multidisciplinary approach that integrates various diagnostic modalities, including clinical examination, dermoscopy, histopathology, molecular testing, radiological imaging, and blood tests. While surgery is the preferred method of treatment for AM, other therapeutic options may be employed based on the stage and underlying etiology of the disease. Immune checkpoint inhibitors, molecular targeted therapy, radiotherapy, chemotherapy, and oncolytic virotherapy represent promising advanced treatment options for AM. In this review, we provide an overview of the latest advancements in diagnostic and therapeutic methods for AM, highlighting the importance of early detection and the prompt, individualized management of this challenging disease.

Survival benefit of sentinel lymph node biopsy in Asian melanoma patients

Sentinel lymph node biopsy (SLNB) provides important prognostic information for early-stage melanomas. However, statistics regarding the survival comparison between SLNB and nodal observation in Asia, where acral lentiginous melanoma (ALM) predominates, are limited. This study aimed to identify if SLNB offered survival benefits over nodal observation in early-stage melanomas in Taiwan. The retrospective study included 227 patients who met the SLNB criteria according to the National Comprehensive Cancer Network guidelines and were treated at National Taiwan University Hospital from June 1997 to June 2021. Survival analysis was performed using Kaplan-Meier curves and Cox proportional hazards regression models. Of the study population, ALM accounted for 73.1%; 161 patients (70.9%) underwent SLNB and 66 patients (29.1%) were under nodal observation. Multivariate analysis showed significantly improved melanoma-specific survival (hazard ratio [HR], 0.6; p = .02) in the SLNB group. Among those who underwent completion lymph node dissection (CLND), the non-sentinel node positivity rate was 44.4%. Immediate CLND resulted in significantly longer melanoma-specific survival and distant-metastasis-free survival (DMFS) compared to nodal observation. (HR, 0.2; p = .01 for melanoma-specific survival. HR, 0.3; p = .046 for DMFS). In conclusion, SLNB may provide survival benefits of cutaneous melanoma over nodal observation in the Taiwanese population.

The genetic evolution of acral melanoma

Acral melanoma is an aggressive type of melanoma with unknown origins, arising on the sole, palm, or nail apparatus. It is the most common type of melanoma in individuals with dark skin and is notoriously challenging to treat. Our study examined exome sequencing data from 139 tissue samples, spanning different progression stages, collected from 37 patients. We found that 78.4% of the melanomas displayed one or more clustered copy number transitions with focal amplifications, recurring predominantly on chromosomes 5, 11, 12, and 22. These genomic "hailstorms" were typically shared across all progression stages within individual patients. Genetic alterations known to activate TERT also arose early. By contrast, mutations in the MAP-kinase pathway appeared later during progression, often leading to different tumor areas harboring non-overlapping driver mutations. We conclude that the evolutionary trajectories of acral melanomas substantially diverge from those of melanomas on sun-exposed skin, where MAP-kinase pathway activation initiates the neoplastic cascade followed by immortalization later. The punctuated formation of hailstorms, paired with early TERT activation, suggests a unique mutational mechanism underlying the origins of acral melanoma. Our findings highlight an essential role for telomerase, likely in re-stabilizing tumor genomes after hailstorms have initiated the tumors. The marked genetic heterogeneity, in particular of MAP-kinase pathway drivers, may partly explain the limited success of targeted and other therapies in treating this melanoma subtype.

Diagnosis and Management of Acral Pigmented Lesions

BACKGROUND

Survival outcomes in acral lentiginous melanoma (ALM) are worse than for cutaneous melanoma. Diagnostic delays are believed to contribute to worse outcomes in ALM, including advanced-stage disease at initial presentation. Acral lentiginous melanoma, especially in its early stages, may be difficult to discern from benign pigmented acral lesions.

OBJECTIVE

The purpose of this article is to provide a comprehensive review of the diagnosis and management of acral pigmented lesions.

MATERIALS AND METHODS

A literature review was performed. The outcomes included were the clinical and dermoscopic features and the management frameworks and considerations for acquired and congenital melanocytic nevi, acral melanosis, nonmelanocytic pigmented lesions, and ALM.

RESULTS

Original research studies were primarily included. The use of dermoscopy, such as the 3-step algorithm and blotch (irregular), ridge pattern (parallel), asymmetry of structures, asymmetry of colors, furrow pattern (parallel), fibrillar pattern (BRAAFF) checklist, increases the diagnostic accuracy of acral pigmented lesions with high specificity and sensitivity. Short-term digital dermoscopic surveillance can be used to manage acral lesions, and histopathology should be collected when there is a concern for ALM.

CONCLUSION

The use of dermoscopy and an understanding of how to manage acral lesions may limit the number of biopsies performed on the acral skin, decrease the time to diagnosis, and facilitate early detection of ALM.

PAK1 and Therapy Resistance in Melanoma

Malignant melanoma claims more lives than any other skin malignancy. While primary melanomas are usually cured via surgical excision, the metastatic form of the disease portents a poor prognosis. Decades of intense research has yielded an extensive armamentarium of anti-melanoma therapies, ranging from genotoxic chemo- and radiotherapies to targeted interventions in specific signaling pathways and immune functions. Unfortunately, even the most up-to-date embodiments of these therapies are not curative for the majority of metastatic melanoma patients, and the need to improve their efficacy is widely recognized. Here, we review the reports that implicate p21-regulated kinase 1 (PAK1) and PAK1-related pathways in the response of melanoma to various therapeutic modalities. Ample data suggest that PAK1 may decrease cell sensitivity to programmed cell death, provide additional stimulation to growth-promoting molecular pathways, and contribute to the creation of an immunosuppressive tumor microenvironment. Accordingly, there is mounting evidence that the concomitant inhibition of PAK1 enhances the potency of various anti-melanoma regimens. Overall, the available information suggests that a safe and effective inhibition of PAK1-dependent molecular processes would enhance the potency of the currently available anti-melanoma treatments, although considerable challenges in implementing such strategies still exist.

Major Histotypes in Skin Melanoma: Nodular and Acral Lentiginous Melanomas Are Poor Prognostic Factors for Relapse and Survival

ABSTRACT

The histological subtype is not considered one of the major prognostic factors in melanoma, yet it is known to have an impact on survival. The aim of this study was to investigate the clinical significance of histological subtypes and the possible impacts of clinicopathological factors on the course of melanoma patients of all stages. A total of 1017 cutaneous melanoma patients were analyzed retrospectively. Four major melanoma histotypes that were studied in this study were as follows: (1) superficial spreading melanoma (SSM), (2) nodular melanoma (NM), (3) acral lentiginous melanoma (ALM), and (4) lentigo maligna melanoma (LMM). Unlike SSMs and LMMs, there were statistically significant correlations between NMs and ALMs and most aggressive histopathological prognostic indicators, such as higher Clark level ( P = 0.0001), thick Breslow depth ( P = 0.0001), presence of ulceration ( P = 0.0001), and lymphovascular invasion ( P = 0.0001). Furthermore, NMs and ALMs were also associated with advanced clinical stages, that is, node involvement and metastasis. Relapse rates for nonmetastatic melanomas were higher in NMs (39.6%) and ALMs (35.3%) than in SSMs (24.3%) and LMMs (10.3%) ( P = 0.0001). Additionally, 5-year relapse-free survival rates were 90.5%, 70.5%, 55.7%, and 50.5% in LMMs, SSMs, ALMs, and NMs, respectively ( P = 0.0001). Moreover, 5-year overall survival rates plummeted from 84.3% in LMMs to 74.8%, 64.3%, and 46% in SSMs, ALMs, and NMs, respectively ( P = 0.0001). In conclusion, we observed that the histologic subtype was an independent predictor for relapse and outcome for cutaneous melanoma patients. Both NM and ALM had unfavorable prognoses, and they were associated with known poor pathological and clinical indicators.

Histopathological Characteristics of Cutaneous Melanoma in Isfahan, Iran, from 2013 to 2018

Objectives. To investigate the histopathological characteristics of cutaneous melanoma in Isfahan from 2013 to 2018, according to histopathological subtype, lesions location, Clark level, and Breslow thickness. Methods. A descriptive, retrospective study in reports of Alzahra Hospital and Dr. Rajabi Pathology Laboratory in Isfahan. Results. In total, 45 patients were included in this study. The most prevalent histopathological subtype was acral lentiginous melanoma (48.89%), followed by lentigo maligna melanoma (17.78%), nodular melanoma (11.11%), and superficial spreading melanoma (8.89%). Most malignant lesions were on the foot and toes (31.1%) and face (24.4%). Tumor invasion level was mainly at Clark level IV (42.2%). Furthermore, the mean depth of tumor penetration (Breslow thickness) was 3.87 ± 3.35. Conclusions. Our study revealed the characteristics of melanoma in the Iranian population. Our results showed a similar trend with previous studies in the Asian population. Further investigations are needed to elucidate the role of ethnic and environmental risk factors for developing melanoma in different populations.

Risk factors for lymphatic and hematogenous metastasis after diagnosis of cutaneous Melanoma in Taiwan

BACKGROUND

Risk factors of lymphatic and hematogenous metastasis in cutaneous melanoma remained unclear in Asian population. This study aimed to identify clinical and histopathological factors to predict metastatic pathways in cutaneous melanoma in Taiwan.

METHODS

A total of 247 patients diagnosed as stage I and II melanoma, followed at National Taiwan University Hospital were included in this retrospective study from 1980 to 2020. Kaplan-Meier curves and Cox proportional hazards regression were utilized to identify risk factors.

RESULTS

During a median follow-up of 143 months, 48 (19.4%) and 62 (25.1%) patients developed lymphatic and hematogenous metastasis respectively. In the univariate analysis, age> 70 years, greater Breslow thickness, ulceration, neurotropism, and NRAS mutation were significant risk factors for lymphatic metastasis in all subtypes of melanoma. Age >70 years, head and neck location, thickness, ulceration, higher mitotic rate, neurotropism, and NRAS mutation were significant predictors of hematogenous metastasis in all subtypes. In the multivariate analysis, greater thickness (HR for 2.0-4.0 mm, 4.5; p = .009 and HR for >4.0 mm, 5.7; p = .003) retained its significance as an independent risk factor for lymphatic metastasis in all subtypes of melanoma. Thickness (HR for >4.0 mm, 5.7; p < .001) and ulceration (HR, 2.5; p = .001) were independent risk factors for hematogenous metastasis.

CONCLUSION

Risk factors of metastasis not only differ between lymphatic and hematogenous pathways, but also differ between ethnics and melanoma subtypes. Better understanding the behavior of cutaneous melanoma may help guide further treatments and follow-up plans.

Acral Melanocytic Neoplasms: A Comprehensive Review of Acral Nevus and Acral Melanoma in Asian Perspective

Acral melanocytic neoplasms, including acral melanocytic nevus and acral melanoma, are common melanocytic lesions in Asian populations. Both lesions occur on the volar surface of the hands and feet, and on nail units. Acral melanocytic nevi occur on the arch area of the sole, whereas acral melanomas frequently occur on weight-bearing areas of the sole, and on the fingernails. Therefore, the development of acral melanoma may be associated with chronic pressure, physical stress, or trauma. Dermoscopy is a useful adjunctive diagnostic tool for differential diagnosis. Acral melanocytic nevus is characterized by a parallel furrow pattern, whereas acral melanoma has a parallel ridge pattern. Genetic alterations are also different between the two types of lesion. BRAF and NRAS mutations are common in acral melanocytic nevus, whereas acral melanoma shows lower rates of KIT, NF1, BRAF, and NRAS mutations and remarkable copy number variations in genes such as CCND1, CDK4, hTERT, PAK1, and GAB2. Sentinel lymph node biopsy is important for staging and prognosis. Contemporary treatments for melanoma include targeted therapy for mutations and immunotherapy, such as anti-PD1 inhibitors.

The pharmacotherapeutic management of nail unit and acral melanomas

INTRODUCTION

Acral and nail unit melanomas are rare subtypes of melanoma, which have poor prognoses. Current guidelines for optimal treatment are lacking. Recent clinical trials have evaluated new pharmacotherapeutic agents for melanoma treatment, with dramatically improved survival rates; however, studies on acral and nail unit melanomas are limited in comparison to trials on cutaneous melanoma.

AREAS COVERED

This is a comprehensive review of the literature regarding the available treatment options for acral and nail unit melanomas, with consideration of safety and tolerability.

EXPERT OPINION

Programmed cell death protein 1 inhibitors are more efficacious than cytotoxic T lymphocyte-associated antigen-4 blockers in acral and nail unit melanomas, although both are well-tolerated. Tyrosine kinase inhibitors have good clinical activity, however, data on safety is relatively limited. There is minimal data on high dose interferon α-2b and cyclin-dependent kinase 4 and 6 inhibitors, and efficacy and safety must be evaluated in future trials before they can be recommended for use in this patient population. Prospective clinical trials on acral and nail unit melanomas are lacking, and must be performed in large patient populations, with international collaboration likely necessary in order to enroll adequate participants.

Racial and Ethnic Healthcare Disparities in Skin Cancer in the United States: A Review of Existing Inequities, Contributing Factors, and Potential Solutions

Objective

Racial and ethnic health disparities affect the diagnosis and management of melanoma and nonmelanoma skin cancers, leading to deleterious outcomes. Non-Hispanic White patients make up the majority of skin cancers cases, yet racial and ethnic minorities have poorer prognoses and outcomes. The skin cancer literature is fragmented with regards to potential contributors to these healthcare disparities. In this article, we provide a comprehensive review of the skin cancer literature to briefly quantify racial and ethnic inequities, highlight contributing factors, and propose practical changes that can be made.

Methods

A PubMed search was completed to identify articles related to racial and ethnic health care disparities in the context of melanoma, basal cell carcinoma, squamous cell carcinoma, Merkel cell carcinoma, and dermatofibrosarcoma protuberans.

Results

Relative to non-Hispanic White patients, patients of racial and ethnic minorities have differing clinical presentations of skin cancers and genetic risk factors. Insurance, access to specialty care, cultural beliefs, and available educational resources further contribute to racial and ethnic disparities.

Limitations

We are limited to the level of detail provided in the existing literature, and at some times are unable to distinguish race of Hispanic populations. We also acknowledge that there are different nationalities grouped under these broad labels as well as multi-racial populations that may not be accounted for.

Conclusion

Awareness of and familiarization with innate factors and potentially more modifiable contributors can help inform efforts to close the observed gap in racial and ethnic inequities.

Racial/Ethnic Health Disparities in Dermatology in the United States Part 2: Disease-specific Epidemiology, Characteristics, Management, and Outcomes

Racial and ethnic disparities in dermatology negatively affect outcomes such as mortality and quality of life. Dermatologists and dermatologic surgeons should be familiar with disease-specific inequities that may influence their practice. The second article in this two-part continuing medical education series highlights gaps in frequency, clinical presentation, management, and outcomes by race and ethnicity. We review cutaneous malignancies including basal cell carcinoma, squamous cell carcinoma, melanoma, Merkel cell carcinoma, dermatofibrosarcoma protuberans, and cutaneous T cell lymphoma, and inflammatory disorders including atopic dermatitis, psoriasis, hidradenitis suppurativa, acne vulgaris, and rosacea.

Different progression pattern between acral and nonacral melanoma: A retrospective, comparative, clinicoprognostic study of 492 cases of primary cutaneous melanoma according to tumor site

BACKGROUND

There are limited data regarding the difference in progression pattern between acral melanoma and nonacral melanoma.

AIMS

The objectives of this study were to compare the progression pattern between acral and nonacral melanoma and evaluate its impact on clinical outcomes.

METHODS

Clinical and histopathological features, survival outcomes and prognostic factors of 492 patients with acral melanoma or nonacral melanoma were retrospectively evaluated using the Asan Medical Center database.

RESULTS

The male-to-female ratio and the mean age was 1:0.92 and 60.2 years for acral melanoma (n = 249), and 1:0.85 and 58.4 years for nonacral melanoma (n = 243), respectively. The demographic difference was not significant. Although prediagnosis duration was longer and the advanced stage was more common in acral melanoma than that in nonacral melanoma, the vertical growth phase was more common in nonacral melanoma than that in acral melanoma, whereas, the horizontal diameter is longer in acral melanoma than that in nonacral melanoma. Dissemination to lymph nodes was more common in acral melanoma than that in nonacral melanoma. Lymph node involvement was associated with deeper Breslow thickness in nonacral melanoma but not in acral melanoma. The degree of correlation of prediagnosis duration with horizontal diameter was remarkable in acral melanoma, but with Breslow thickness in nonacral melanoma. Overall survival was worse in acral melanoma than that in nonacral melanoma. The prognostic value of Breslow thickness was more remarkable in nonacral melanoma than that in acral melanoma.

LIMITATIONS

This study is a retrospective, single-center design.

CONCLUSION

Acral melanoma has a longer radial growth phase compared with nonacral melanoma. However, acral melanoma is commonly associated with lymph node dissemination which contributed to worse survival in acral melanoma than nonacral melanoma.

Acral lentiginous melanoma-Population, treatment, and survival using the NCDB from 2004 to 2015

Acral lentiginous melanoma (ALM) is a rare histological subtype of cutaneous malignant melanoma that typically presents on the palms and soles. To characterize the demographic and treatment characteristics of ALM, we used the National Cancer Database (NCDB) to describe a large multi-institutional cohort of ALM patients, consisting of 4,796 ALM patients from 2004 to 2015. ALM was more likely to be diagnosed at a later stage overall compared with non-ALM cutaneous melanomas, and more likely to be thicker, ulcerated, lymph node positive, and have lymphovascular invasion and positive margins. When stratified by stage, ALM had worse survival compared with non-ALM patients, most notably in stage III patients with 5-year survival of 47.5% versus 56.7%, respectively (p < .001). In ALM patients, older age, male sex, higher comorbidity burden, increased tumor thickness and ulceration, positive lymph nodes, and positive metastasis were independently associated with lower 5-year survival. Multimodality therapy, defined as surgery in addition to systemic therapy and/or radiation therapy, was associated with higher survival in stage III patients but not in other stages. These results call for further investigation into possible treatment intensification in the ALM population in the future.

Factors influencing locoregional recurrence and distant metastasis in Asian patients with cutaneous melanoma after surgery: A retrospective analysis in a tertiary hospital in Taiwan

BACKGROUND

The goal of this study was to investigate the prognostic factors for locoregional recurrence and metastasis in patients with cutaneous melanoma (CM) who underwent surgery, especially in the acral lentiginous melanoma (ALM) subtype.

METHODS

This study was a retrospective review of patients who underwent surgery for CM at Taipei Veterans General Hospital between 2000 and 2018. We investigated the risk factors for locoregional and distant metastases. The association between clinicopathological factors and locoregional recurrence and distant metastasis of the CM and ALM subtypes was analyzed. In addition, the outcomes between the ALM and non-ALM groups were compared.

RESULTS

A total of 161 patients were included in the analysis. The most common histological subtype was ALM. The overall locoregional recurrence rate of CM was 13.0% and the distant metastasis rate was 42.9%, whereas that of the ALM subtype was 12.5% and 45.5%, respectively. In patients with CM, male sex, tumor with lymphovascular invasion, and positive lymph node status were the prognostic factors for both locoregional recurrence and distant metastasis. Among the patients with ALM, positive lymph node status was significantly associated with both locoregional recurrence and distant metastasis.

CONCLUSION

In this cohort, factors influencing locoregional recurrence and distant metastasis were similar between the ALM and non-ALM groups. The above-recommended surgical margin did not show any benefit in either the CM or the ALM subtype. ALM can be handled using the same surgical strategy as CM in the Asian population.

When acral malignant melanoma facades as diabetic foot!

An 85-year-old Indian man presented with non-healing foot ulcer over the left heel. There was initial response to wound size with standard treatment including offloading, debridement and antibiotic therapy. However, subsequently, there was no progress noted. Incidentally, two small black spots in the wound bed raised the suspicion of melanoma. Incisional biopsy confirmed acral lentiginous melanoma (ALM). The final diagnosis was ALM coexisting with diabetic foot ulcer (DFU). The wound was treated by surgical resection and flap reconstruction that resulted in complete healing. Fourteen months after the initial intervention, the patient developed a new lump and ulceration around the previous wound bed. This turned out to be recurrent disease with distant metastasis. The patient died eventually with palliative support. Through this case, we would like to highlight the importance of early biopsy and intervention in DFU especially for those wounds with atypical presentation or refractory to standard treatment.

Management of Nail Unit Melanoma

Nail unit melanoma is an uncommon form of melanoma with worse prognosis compared with nonacral cutaneous melanoma. Nail unit melanoma is often diagnosed at a late stage. Clinical and dermoscopic features may suggest a diagnosis of nail unit melanoma, but confirmation requires histologic analysis. Like the clinical diagnosis, histopathologic diagnosis of nail unit melanoma is also difficult. The surgical management of nail unit melanoma has evolved from aggressive amputations to digit-sparing approaches. This article reviews the clinical presentation, diagnosis, and surgical treatment of nail unit melanoma to promote early diagnosis and rational surgery.

Subtyping Cutaneous Melanoma Matters

Background

Our aim was to investigate the role of melanoma subtype on survival and focus on the effects stratified by Breslow thickness and ulceration status.

Methods

Patients with cutaneous melanoma stage I, II, or III diagnosed between 2000 and 2014 were derived from the Dutch Nationwide Pathology Registry and overall survival data from the Netherlands Cancer Registry. Patients were followed until 2018. Using multivariable Cox proportional hazards models, hazard ratios were calculated for each melanoma subtype, per Breslow thickness category and ulceration status, and adjusted for age, sex, stage, and localization.

Results

A total of 48 361 patients were included: 79.3% had superficial spreading melanoma (SSM), 14.6% nodular melanoma (NM), 5.2% lentigo maligna melanoma, and 0.9% acral lentiginous melanoma (ALM). In the total patient group, using SSM as the reference category, adjusted hazard ratios were 1.06 (95% confidence interval [CI] = 1.01 to 1.12) for NM, 1.02 (95% CI = 0.93 to 1.13) for lentigo maligna melanoma, and 1.26 (95% = CI 1.06 to 1.50) for ALM. Among patients with 1.0 mm or less Breslow thickness and no ulceration, NM showed a twofold increased risk (hazard ratio = 1.96, 95% CI = 1.58 to 2.45) compared with SSM. Compared with 1.0 mm or less SSM without ulceration, the hazard ratio for 1.0 mm or less SSM with ulceration was 1.94 (95% CI = 1.55 to 2.44), and the hazard ratio for 1.0 mm or less NM with ulceration was 3.46 (95% CI = 2.17 to 5.50). NM patients with tumors greater than 1.0 mm did not show worse survival than SSM patients with tumors greater than 1.0 mm.

Conclusions

In this large nationwide study, ALM patients showed worse survival than SSM patients. Among patients with melanomas that were thin (1.0 mm or less), NM subtype patients also showed worse survival than SSM patients.

Lymphatic invasion in acral and non-acral melanoma: a comparative, clinicoprognostic study of primary cutaneous melanoma according to tumour site

There have been limited studies comparing the clinical significance of lymphatic invasion in melanoma according to tumour site. The objective of this study was to evaluate the impact of lymphatic invasion on the clinicoprognostic features of acral and non-acral melanoma. Clinical and histopathological features and survival outcomes of 532 patients with acral melanoma or non-acral melanoma in the database of the Asan Medical Center, Korea, were retrospectively evaluated according to the presence of lymphatic invasion. Lymphatic invasion was significantly more common in acral melanoma than non-acral melanoma. In acral melanoma, lymphatic invasion was significantly associated with a higher frequency of lymph node involvement and advanced stages, but not associated with Breslow thickness or visceral dissemination. By contrast, lymphatic invasion in non-acral melanoma was significantly associated with a higher rate of visceral involvement, deeper Breslow thickness, as well as a higher rate of lymph node involvement and advanced stages. When acral melanoma and non-acral melanoma both with lymphatic invasion were compared, Breslow thickness was significantly shallower and vertical growth phase was significantly less common in acral melanoma. Meanwhile, visceral involvement was significantly more frequent in non-acral melanoma than acral melanoma. In conclusion, lymphatic invasion was more common in acral melanoma than non-acral melanoma and occurred in acral melanoma cases with relatively thin Breslow thickness, suggesting acral melanoma is lymphotropic.

The ongoing racial disparities in melanoma: An analysis of the Surveillance, Epidemiology, and End Results database (1975-2016)

BACKGROUND

Although most patients with cutaneous melanoma are non-Hispanic whites (NHWs), minorities consistently suffer worse melanoma-specific survival (MSS). Much of the literature comes from analyses of registries from the 1990s and 2000s.

OBJECTIVE

We sought to evaluate whether and to what degree racial disparity in MSS persists since 2010.

METHODS

We analyzed 381,035 patients from the Surveillance, Epidemiology, and End Results registry. Race categories included Hispanic, NHW, non-Hispanic black (NHB), non-Hispanic Asian or Pacific Islander (NHAPI), and non-Hispanic American Indian/Alaska Native (NHAIAN). We evaluated the association between MSS and race in 3 time periods: before the year 2000, 2000 to 2009, and 2010 or later. NHW was the reference group for all analyses.

RESULTS

Racial disparity worsened from before the year 2000 to 2010 or later for Hispanic (P < .001), NHB (P = .024), and NHAPI (P < .001) patients. Across all minority groups, patients with localized disease suffered increasing disparity (P = .010 for Hispanic, P < .001 for NHB, P = .023 for NHAPI, and P = .042 for NHAIAN patients). Among those with regional and distant disease, Hispanic patients were the only minority to experience worsening disparity (P = .001 and P = .019, respectively).

LIMITATIONS

Lack of immunotherapy and targeted treatment information.

CONCLUSIONS

Racial disparity in MSS is worsening. Improving postdiagnosis management for minorities with localized disease is imperative to mitigate disparity and improve survival.

Acral Lentiginous Melanoma: Do Surgical Approach and Sentinel Lymph Node Biopsy Matter?

Management of acral lentiginous melanoma (ALM) remains controversial. Traditionally, ALM was managed with digit amputation (DA), resulting in significant morbidity, but recent evidence has advocated for digit sparing management. Furthermore, the significance of nodal metastasis for ALM is not well reported. The aims of this study were to determine if surgical approach for primary ALM impacts outcomes and to evaluate the predictive value of nodal status for ALM.

The rule of 10s versus the rule of 2s: High complication rates after conventional excision with postoperative margin assessment of specialty site versus trunk and proximal extremity melanomas

Specialty site melanomas on the head and neck, hands and feet, genitalia, and pretibial leg have higher rates of surgical complications after conventional excision with postoperative margin assessment (CE-POMA) compared with trunk and proximal extremity melanomas. The rule of 10s describes complication rates after CE-POMA of specialty site melanomas: ∼10% risk for upstaging, ∼10% risk for positive excision margins, ∼10% risk for local recurrence, and ∼10-fold increased likelihood of reconstruction with a flap or graft. Trunk and proximal extremity melanomas encounter these complications at a lower rate, according to the rule of 2s. Mohs micrographic surgery (MMS) with frozen section melanocytic immunostains (MMS-I) and slow Mohs with paraffin sections decrease complications of surgery of specialty site melanomas by detecting upstaging and confirming complete tumor removal with comprehensive microscopic margin assessment before reconstruction. This article reviews information important for counseling melanoma patients about surgical treatment options and for developing consensus guidelines with clear indications for MMS-I or slow Mohs.

Acral Melanoma: A Patient's Experience and Physician's Commentary

This article, co-authored by a patient diagnosed with acral melanoma, discusses the patient's experience of being diagnosed with and treated with surgery for this disease. The physician discusses the epidemiology, genetics, diagnosis, treatment, and prognosis of acral melanoma. Follow-up care plans are also discussed.

Surgical Management of Plantar Melanoma: A Retrospective Study in One Center

Cutaneous melanoma is a highly malignant skin tumor, and in China, the planta pedis is a commonly involved site. The sites of plantar melanomas are a challenge to reconstruct after wide excision. Our experience with surgical management of melanomas was based on the 4 different anatomic subunits of the planta pedis. From January 1, 2002 to December 31, 2016, 35 patients who had had plantar melanoma had undergone surgical treatment in our clinic. The tumor locations were as follows: the toe in 6, the ball of the foot in 5, the arch in 15, and the heel in 9. Surgical management involved extended resection of the tumor, repair of defects with skin grafts or flaps, and inguinal lymphadenectomy. The skin flaps included a residual toe flap, an anterograde or retrograde medial plantar flap, and a retrograde sural neurocutaneous vascular flap. Of the 35 cases of flaps and skin grafts, 33 (94.29%) survived, and the wounds had healed by first intention. After a follow-up period of 6 months to 7 years, 24 patients (68.57%) were free of local and systemic disease and 30 patients (85.71%) were ambulatory using shoes, and all the flaps and skin grafts showed a good appearance. The personalized surgical treatments we used for melanoma in the planta pedis resulted in overall satisfactory outcomes and adequate disease clearance, and allowed the patients to resume normal lives. The function of the foot was maintained or restored to the greatest possible degree, and the patients' quality of life improved postoperatively.

Acral lentiginous melanoma: a skin cancer with unfavourable prognostic features. A study of the German central malignant melanoma registry (CMMR) in 2050 patients

BACKGROUND

Acral lentiginous melanoma (ALM) is one of the four major subtypes in cutaneous melanoma (CM). Although ALM has a poorer prognosis than other CM subtypes, the prognostic factors associated with ALM have only been verified in small-sized cohorts because of the low incidence of ALM worldwide.

OBJECTIVES

To investigate the clinical characteristics of ALM and to evaluate their prognostic values based on a large dataset from the Central Malignant Melanoma Registry (CMMR) of the German Dermatologic Society.

METHODS

The Kaplan-Meier method was used to estimate the potential influence of clinical and histological parameters on ALM disease-specific survival (DSS) curves, which were compared using the log-rank test. A Cox proportional hazards model was used to identify independent prognostic factors for DSS.

RESULTS

In total, 2050 patients with ALM were identified from 58 949 patients with CM recorded by the CMMR with follow-up data. In multivariate analyses, age (P = 0·006), ulceration (P = 0·013), tumour thickness (P < 0·001) and tumour spread (P < 0·001) turned out to be significant prognostic factors for DSS in ALM whereas sex, nevus association and level of invasion were not independent factors.

CONCLUSIONS

ALM has the same prognostic factors as other subtypes of melanoma. Unfavourable prognosis probably derives from the delay in diagnosis in comparison with other melanoma subtypes.

Prognostic role of the histological subtype of melanoma on the hands and feet in Caucasians

Acral melanoma (AM) is associated with a poor prognosis in part because of delayed diagnosis, but probably also because of other intrinsic characteristics of location. The aim of this study was to review the specific characteristics and outcome of AM in Caucasians. This was a cross-sectional retrospective clinical-pathological study of 274 patients identified with AM in the database of a referral unit in Europe from 1986 to 2010. The mean age of the patients was 56.6 (SD 17.7) years. 269 cases could be histologically classified and included in the study. In all, 222 (82.5%) were located on feet. According to melanoma subtype, 165 (61.3%) were acral lentiginous melanoma (ALM), 84 (31.2%) were superficial spreading melanoma (SSM), and 20 (7.5%) were nodular melanoma (NM). SSM patients were characterized by female predominance (77.4%), younger age, and classic melanoma-risk phenotype (fair skin and multiple nevi). Among the 198 invasive cases with a mean follow-up of 56.2 months, the mean (SD) Breslow's thickness was 3.1 (3.6) mm, being 1.4 (1.4) mm in SSM, 3.5 (4.1) mm in ALM and 4.9 (2.9) mm in NM (P<0.001). Ulceration was present in 33.3%, 2.9% in SSM, 38.6% in ALM, and 76.9% in NM (P<0.001). A total of 29.3% relapsed (7.3% of SSM, 35% of ALM and 55% of NM) and 24.2% died because of AM. In multivariate analysis, age at diagnosis, Breslow, and histopathological subtype were independent prognostic factors for both disease-free and AM-specific survival. The ALM and NM subtypes presented poorer outcome after weighting Breslow and age (P=0.02). Histological subtype of AM could have an impact on biological behavior, ALM and NM subtypes presenting a poorer prognosis after adjusting for age and Breslow's thickness.

Improving the diagnosis and treatment of acral melanocytic lesions

Melanocytic lesions of acral sites are common, with an estimated prevalence of 28-36% in the USA. While the majority of these lesions are benign, differentiation from acral melanoma (AM) is often challenging. AM is a unique subtype of melanoma, with distinct molecular characteristics that are thought to contribute to its high rate of locoregional recurrence and worse prognosis. The advent of dermoscopy has since improved the diagnostic accuracy of AM, resulting in earlier detection and arguably improved survival. Additionally, the identification of unique genomic amplifications in AM invites the potential for future AM-specific targeted therapies. Herein, we discuss the importance of dermoscopy in the diagnosis of acral melanocytic lesions and review the treatment strategies for AM.

Disease stabilization with pembrolizumab for metastatic acral melanoma in the setting of autoimmune bullous pemphigoid

Background

To date, patients with pre-existing autoimmune conditions have been excluded from immunotherapy trials out of concern for severe autoimmune exacerbations.

Case Presentation

We describe the first case of a patient with metastatic cKIT mutated acral melanoma, brain metastasis, and pre-existing severe autoimmune bullous pemphigoid (BP) with stable and asymptomatic disease 10 months after treatment with pembrolizumab. The patient experienced severe BP exacerbation after therapy with ipilimumab requiring systemic immune suppression, but nonetheless pembrolizumab was administered on further disease progression.

Conclusions

This case suggests that pembrolizumab may confer more benefit than risk even in patients with known severe autoimmune conditions who require intermittent systemic immunosuppression.

Novel Therapies for Metastatic Melanoma: An Update on Their Use in Older Patients

Cutaneous melanoma is the most aggressive form of skin cancer. With age as a risk factor, melanoma is projected to become a substantial healthcare burden. The clinical course of melanoma in older patients is different from that in middle-aged and younger patients: melanomas are thicker, have higher mitotic rates and are more likely to be ulcerated. Older patients also have a higher mortality rate, yet, paradoxically, have a lower rate of lymph node metastases. After decades of no significant progress in the treatment of this devastating disease, novel insights into the mechanisms underlying the pathophysiology of metastatic melanoma have led to new and remarkably efficient therapeutic opportunities. The discovery that about half of all melanomas carry BRAF mutations led to the introduction of targeted therapy with significant improvements in clinical outcomes. Although these drugs appear to be equally effective in older patients, specific considerations regarding adverse events are required. Besides targeted therapy, immunotherapy has emerged as an alternative therapeutic option. Antibodies that block cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed cell death protein 1 (PD-1) can induce responses with high durability. Despite an aging immune system, older patients seem to benefit to the same degree from these treatments, apparently without increased toxicity. In this review, we focus on the epidemiology, clinicopathological features, and recent developments of systemic treatment in cutaneous melanoma with regard to older patients.