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The incidence of primary cutaneous melanoma has been increasing dramatically for several decades. Melanoma accounts for the majority of skin cancer-related deaths, but treatment is nearly always curative with early detection of disease. In this update of the guidelines of care, we will discuss the treatment of patients with primary cutaneous melanoma. We will discuss biopsy techniques of a lesion clinically suspicious for melanoma and offer recommendations for the histopathologic interpretation of cutaneous melanoma. We will offer recommendations for the use of laboratory and imaging tests in the initial workup of patients with newly diagnosed melanoma and for follow-up of asymptomatic patients. With regard to treatment of primary cutaneous melanoma, we will provide recommendations for surgical margins and briefly discuss nonsurgical treatments. Finally, we will discuss the value and limitations of sentinel lymph node biopsy and offer recommendations for its use in patients with primary cutaneous melanoma. [ABSTRACT FROM AUTHOR]

Full-thickness dermal biopsies were performed in healthy volunteers to establish the range of angiogenic responses in wound healing in a normal population. Four-millimeter punch biopsies were made in the forearms of 15 healthy volunteers. Each wound was evaluated microscopically 4-5 times per week for 2 weeks. A semiquantitative wound scoring system to evaluate the neovasculature at the wound periphery was investigated. A vascular score was calculated for each wound at each observation. Two independent observers analyzed the microscopic wound images using the scoring system. At the end of the 14-day period, repeat biopsies were performed on some of the volunteers, and the granulation tissue was stained with anti-CD31. The Kaplan-Meier method was used to estimate the distribution of the time to reach predetermined target average vascular scores. A mixed-effects regression model indicated that time, age, and observer were predictors for the average vascular score outcome. The pattern and time course for wound neovascularization was highly reproducible in this group of healthy volunteers, and the assay was feasible and well tolerated. This wound angiogenesis model may be useful for monitoring the effects of antiangiogenic agents on normal wound neovascularization. [ABSTRACT FROM AUTHOR]

Background: Patients with skin lesions suspicious for skin cancer or atypical melanocytic nevi of uncertain malignant potential often present to dermatologists, who may have variable dermoscopy triage clinical experience., Objective: To evaluate the clinical utility of a digital dermoscopy image-based artificial intelligence algorithm (DDI-AI device) on the diagnosis and management of skin cancers by dermatologists., Methods: Thirty-six United States board-certified dermatologists evaluated 50 clinical images and 50 digital dermoscopy images of the same skin lesions (25 malignant and 25 benign), first without and then with knowledge of the DDI-AI device output. Participants indicated whether they thought the lesion was likely benign (unremarkable) or malignant (suspicious)., Results: The management sensitivity of dermatologists using the DDI-AI device was 91.1%, compared to 84.3% with DDI, and 70.0% with clinical images. The management specificity was 71.0%, compared to 68.4% and 64.9%, respectively. The diagnostic sensitivity of dermatologists using the DDI-AI device was 86.1%, compared to 78.8% with DDI, and 63.4% with clinical images. Diagnostic specificity using the DDI-AI device increased to 80.7%, compared to 75.9% and 73.6%, respectively., Conclusion: The use of the DDI-AI device may quickly, safely, and effectively improve dermoscopy performance, skin cancer diagnosis, and management when used by dermatologists, independent of training and experience.

Competing Interests: None disclosed.

Hair graying holds psychosocial importance and serves as an excellent model for studying human pigmentation and aging in an accessible miniorgan. Current evidence suggests that graying results from an interindividually varying mixture of cumulative oxidative and DNA damage, excessive mTORC1 activity, melanocyte senescence, and inadequate production of pigmentation-promoting factors in the hair matrix. Various regulators modulate this process, including genetic factors (DNA repair defects and IRF4 sequence variation, peripheral clock genes, P-cadherin signaling, neuromediators, HGF, KIT ligand secretion, and autophagic flux. This leads to reduced MITF- and tyrosinase-controlled melanogenesis, defective melanosome transfer to precortical matrix keratinocytes, and eventual depletion of hair follicle (HF) pigmentary unit (HFPU) melanocytes and their local progenitors. Graying becomes irreversible only when bulge melanocyte stem cells are also depleted, occurring later in this process. Distinct pigmentary microenvironments are created as the HF cycles: early anagen is the most conducive phase for melanocytic reintegration and activation, and only during anagen can the phenotype of hair graying and repigmentation manifest, whereas the HFPU disassembles during catagen. The temporary reversibility of graying is highlighted by several drugs and hormones that induce repigmentation, indicating potential target pathways. We advise caution in directly applying mouse model concepts, define major open questions, and discuss future human antigraying strategies., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Competing Interests: Dr Correa-Selm is a consultant for Accutec and a consultant and researcher for Novartis Pharmaceutical, also serves on the Advisory Board for the Jacinto Convit World Organization and the Dermatology Advisory for Melanoma Research Foundation. Dr Grichnik is a consultant for Galileo Group and Canfield Scientific; serves on the Skin Advisory Board for Regeneron and the Dermatology Advisory for Melanoma Research Foundation; and receives clinical trial support from Novartis, Eli Lilly, Dermira, Elorac, Boehringer, and Amgen. Author Milani, Author Hanlon, and Dr Chen have no conflicts of interest to declare.

Background: We present a case of RCM evaluation of ALM surgical margins demonstrating intracorneal melanocytic bodies overlying subsequently confirmed melanoma in situ by histopathology., Case Presentation: A 73-year-old male with a history of acral lentiginous melanoma (ALM) of the right great toe presented to our clinic for evaluation of positive surgical margins. The positive margin was localized for examination and subsequent biopsy with reflectance confocal microscopy (RCM) which allowed targeted re-resection of the area of concern. Three punch biopsies were obtained in the area of concern, which confirmed residual melanoma in situ. Immunostains confirmed the cellular remnants in the stratum corneum were melanocytic. To correlate the intra stratum corneum findings seen with confocal to the histopathology, a 3D rendering of a stack of images was used to demonstrate the location., Discussion: Typically, acral surfaces are challenging to examine with RCM due to the limited ability of light to penetrate thickened stratum corneum; however, we observed unique cellular features with confocal. Scattered hyper-reflective pleomorphic cells consistent with melanocytes were observed in the stratum corneum, although the visualized underlying epidermis appeared normal. Confocal microscopy may aid in diagnosis and management of ALM, especially in the context of positive surgical margins., (© 2023 Wiley Periodicals LLC.)

Competing Interests: Declaration of interests We declare no competing interests.

Significance: Dermoscopes incorporate light, polarizers, and optical magnification into a handheld tool that is commonly used by dermatologists to evaluate skin findings. Diagnostic accuracy is improved when dermoscopes are used, and some major artificial intelligence (AI) projects have been accomplished using dermocopic images. Color rendering consistency and fidelity are crucial for clinical diagnostics, AI, and image processing applications., Aim: With many devices available on the market, our objective was to measure the emission spectra of various dermoscopes, compare them with other light sources, and illustrate variations in reflected colors from images of a reference sample., Approach: A spectrometer measured the spectral power distribution (SPD) produced by four dermoscope models and three alternate light sources, illustrating differences in the emission spectra. Most dermoscopes use light-emitting diodes (LEDs), which are inconsistent when compared with one another. An LED was compared with halogen, xenon-arc, and daylight sources. Images of a micro ColorChecker were acquired from several sources, and three specific colors were selected to compare in CIELAB color space. Color consistency and color fidelity measured by color rendering index (CRI) and TM-30-18 graphical vectors show variation in saturation and chroma fidelity., Results: A marked degree of variation was observed in both the emission and reflected light coming from different dermoscopes and compared with other sources. The same chromophores appeared differently depending on the light source used., Conclusions: A lack of uniform illumination resulted in inconsistent image color and likely impacted metamerism and visibility of skin chromophores in real-world settings. Artificial light in skin examinations, especially LEDs, may present challenges for the visual separation of specific colors. Attention to LEDs SPD may be important, especially as the field increases dependency on machine/computer vision., (© 2022 The Authors.)

Objectives: Reflectance confocal microscopy (RCM) generates scalar image data from serial depths in the skin, allowing in vivo examination of cellular features. The maximum imaging depth of RCM is approximately 250 µm, to the papillary dermis, or upper reticular dermis. Frequently, important diagnostic features are present in the dermis, hence improved visualization of deeper levels is advantageous., Methods: Low contrast and noise in dermal images were improved by employing a combination of wavelet-based transformations and contrast-limited adaptive histogram equalization., Results: Preserved details, noise reduction, increased contrast, and feature enhancement were observed in the resulting processed images., Conclusions: Complex and combined wavelet-based enhancement approaches for dermal level images yielded reconstructions of higher quality than less sophisticated histogram-based strategies. Image optimization may improve the diagnostic accuracy of RCM, especially for entities with dermal findings., (© 2021 Wiley Periodicals LLC.)

Competing Interests: Dr Grichnik serves as a consultant for Galileo Group, Canfield Scientific and has previously received equipment and meeting support from Caliber Imaging and Diagnostics. Dr Correa-Selm served as speaker of Accutec Blades and was a consultant for Castle Biosciences. Authors Blumstein and Hanlon and Drs Chen and Elgart have no conflicts of interest to declare.

Histologically undetermined early acral melanoma in situ (HUAMIS) is rare but a diagnostic challenge, being clinically and dermoscopically MIS (late onset, a large size (>7 mm), parallel ridges pattern) but microscopically without recognizable cytological atypia. Cyclin D1 (CCND1) gene amplification is a genetic aberration occurring in the early radial growth phase of AMs and could thus help determine malignancy for this disease. We determine the value of CCND1 amplification by FISH as a diagnostic marker for HUAMIS. CCND1 amplification was examined in paraffin-embedded skin biopsies and excisions using a dual-probes fluorescence in situ hybridization (FISH) (11q13 and CEP11). One FISH-negative case 6 was additionally examined by Mypath Melanoma (qRT-PCR). Seventeen cases (12 dysplastic nevi, 3 AMIS, and 2 invasive AM) were served as negative controls for FISH. All six patients (4 females and 2 males) were Hispanic. Pigment lesions were on the left plantar foot (4), right third finger palm (1), and right thumb subungual (1). All cases showed similar clinical and dermoscopical characteristics, including late onset (50 to 74 years old), long duration (from 2 to 15 years), large-sized pigments (from 16 to 40 mm), and a parallel ridge pattern. Junctional melanocytes with no or minimal atypia from five cases showed CCND1 amplifications. Four of 5 cases were received 1st or/and 2nd wide excisions, which demonstrated foci of histologically overt MIS. One FISH-negative case 6 demonstrated "likely malignancy" scores (>2) by Mypath Melanoma (qRT-PCR). None of negative controls showed the amplification. We propose here a simple CCND1 FISH is a practical diagnostic test to determine the malignancy of the very early progression phase of AM preceding histopathologically defined MIS. Cases presented here could be an indolent subtype of AMIS characterized by carrying a long latent radial growth phase without vertical growth, mimicking lentigo maligna., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Cherry hemangiomas are common vascular proliferative lesions that can be concerning from a cosmetic perspective. Laser therapy is often used to eradicate cherry hemangiomas, but some lesions require multiple treatments or do not resolve at all. The suboptimal response to laser treatment may be due to limitations in penetration depth by vascular lasers such as the pulsed dye laser. Optical coherence tomography is a low-energy, light-based imaging device that can evaluate the depth and extent of vascular lesions such as cherry hemangiomas by allowing visualization of tissue structure and blood vessel architecture, which cannot be appreciated by clinical or dermatoscopic examination alone. We present optical coherence tomography images of a cherry hemangioma to demonstrate the precision and resolution of this imaging modality. Optical coherence tomography provides valuable information that has the potential to predict response to laser therapy without unnecessary attempts. Future prospective studies will determine its value for this purpose. , , J Drugs Dermatol. 2016;15(6):713-714.

Background: Acral lentiginous melanoma has increased mortality compared with other melanoma subtypes and disproportionately affects ethnic minorities. Acral melanocytic lesions have not been well studied in diverse populations of the United States., Objective: We sought to assess the prevalence, awareness, and dermoscopic patterns of acral melanocytic lesions in skin-of-color and non-Hispanic white patients., Methods: We prospectively examined the palms and soles of 1052 patients presenting to dermatology clinics in New York, NY, and Miami, FL, from October 2013 to April 2015., Results: Acral melanocytic lesions were observed in 36% of our cohort. Skin-of-color patients were more likely to have acral melanocytic lesions than non-Hispanic white patients (P < .01). Acral melanocytic lesions correlated with increased mole counts, particularly on non-Hispanic white patients. The majority of lesions demonstrated benign dermoscopic patterns. We observed 2 lesions with the parallel ridge pattern in our cohort, both found to be atypical nevi on biopsy specimen. Patients often lacked awareness of the presence of their lesions., Limitations: Interobserver variability in assessing dermoscopic patterns is a limitation., Conclusions: Melanocytic lesions of the palms and soles are common, particularly in a cohort of multiple ethnicities from the United States. Dermoscopy of acral lesions is an important clinical tool for diagnosis and management of these lesions., (Copyright © 2015 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.)

Detection and removal of melanoma, before it has metastasized, dramatically improves prognosis and survival. The purpose of this chapter is to (1) summarize current methods of melanoma detection and (2) review state-of-the-art detection methods and technologies that have the potential to reduce melanoma mortality. Current strategies for the detection of melanoma range from population-based educational campaigns and screening to the use of algorithm-driven imaging technologies and performance of assays that identify markers of transformation. This chapter will begin by describing state-of-the-art methods for educating and increasing awareness of at-risk individuals and for performing comprehensive screening examinations. Standard and advanced photographic methods designed to improve reliability and reproducibility of the clinical examination will also be reviewed. Devices that magnify and/or enhance malignant features of individual melanocytic lesions (and algorithms that are available to interpret the results obtained from these devices) will be compared and contrasted. In vivo confocal microscopy and other cellular-level in vivo technologies will be compared to traditional tissue biopsy, and the role of a noninvasive "optical biopsy" in the clinical setting will be discussed. Finally, cellular and molecular methods that have been applied to the diagnosis of melanoma, such as comparative genomic hybridization (CGH), fluorescent in situ hybridization (FISH), and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), will be discussed.

Identification and removal of melanoma early in its development remains the most effective treatment. However, identification of early melanoma remains challenging and may result in unnecessary morbidity due to the excess excision of benign melanocytic nevi. Herein, we present a conceptual model of benign and malignant melanocytic growths. The potential differences in the location of the cell of origin as well as considerations for neoplasm progression are also reviewed. Several of the clinical tools currently available, the integration of information from those different sources, and approaches to set an optimum biopsy threshold are discussed. While early detection remains a challenge, significant progress has been made. Insight into melanoma growth processes and appropriate use of available tools can result in the detection of thinner melanomas while also decreasing overall biopsy rates., Competing Interests: Financial & competing interests disclosure JM Grichnik has served as a consultant for Amgen, Caliber Imaging & Diagnostics, Inc., Castle Biosciences, and Novartis and is a major shareholder in DigitalDerm, Inc. This manuscript was supported by the Anna Fund Melanoma Program at Sylvester Comprehensive Cancer Center, and the Frankel Family Division of Melanocytic Tumors, Department of Dermatology and Cutaneous Surgery, University of Miami and benefactors especially W Rubin and his family and friends. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript.

Importance: The management of clinically atypical nevi/dysplastic nevi (CAN/DN) is controversial, with few data to guide the process. Management recommendations for DN with positive histologic margins were developed by the Delphi method to achieve consensus among members of the Pigmented Lesion Subcommittee (PLS) of the Melanoma Prevention Working Group (MPWG) after reviewing the current evidence., Objectives: To outline key issues related to the management of CAN/DN: (1) biopsies of CAN and how positive margins arise, (2) whether incompletely excised DN evolve into melanoma, (3) current data on the outcomes of DN with positive histologic margins, (4) consensus recommendations, and (5) a proposal for future studies, including a large-scale study to help guide the management of DN with positive margins., Evidence Review: The literature, including recent studies examining management and outcomes of DN with positive margins between 2009 to 2014, was reviewed., Findings: A consensus statement by the PLS of the MPWG following review of the literature, group discussions, and a structured Delphi method consensus., Conclusions and Relevance: This consensus statement reviews the complexities of management of CAN/DN. A review of the literature and 2 rounds of a structured Delphi consensus resulted in the following recommendations: (1) mildly and moderately DN with clear margins do not need to be reexcised, (2) mildly DN biopsied with positive histologic margins without clinical residual pigmentation may be safely observed rather than reexcised, and (3) observation may be a reasonable option for management of moderately DN with positive histologic margins without clinically apparent residual pigmentation; however, more data are needed to make definitive recommendations in this clinical scenario.

Inflammatory pathways serve to protect the host and promote tissue healing/repair; however, over-activation or dysregulation can be pathological with unintended consequences including malignant progression. A correlation between inflammation and cancer has been well established, and anti-inflammatory medications have been shown to be chemopreventive in certain malignancies. Data are now becoming available that outline an inflammatory pathway that may have a critical role in melanomagenesis. ATP-regulated membrane channels/receptors P2X7 and PANX1 have been directly implicated in melanoma tumor growth. Among other potential effects, opening of the P2X7/PANX1 channel results in activation of the NALP3 inflammasome, which in turn leads to caspase-1 activation and increased levels of activated IL-1β. Elevated levels of caspase-1 and IL-1β have been correlated with melanoma progression, and inhibitors of the inflammasome, caspase and IL-1β activity have all been shown to inhibit melanoma growth. Among many other potential actions, IL-1β increases cyclooxygenase-2 expression leading to local increases in inflammatory mediators such as prostaglandin E2 (PGE2). Anti-inflammatory medications targeting the end of this pathway have had positive results for certain cancers but overall remain mixed for melanoma. A better understanding of the pathways and appropriate intervention points may help direct future therapies. In this viewpoint, we will review data and attempt to model an inflammatory pathway that may be critical for melanomagenesis and propose future directions for exploration., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: The identification of BRAF mutations in melanoma led to the development and implementation of new and effective therapies. Few clinical and histological features have been associated with this mutational status., Objectives: The main objective of this study was to investigate clinical, histopathological and dermoscopic characteristics of primary melanomas according to BRAF or NRAS mutational status., Methods: An observational retrospective study including melanoma dermoscopy images assessed for somatic mutations in BRAF and NRAS., Results: Seventy-two patients were included, 30 women (42%) and 42 men (58%), mean age was 59 ± 15.51 years. BRAF-mutated melanomas were more frequently located on the trunk (n = 18, 64% for BRAF-mutated vs. n = 11, 29% for wild-type melanomas, P = 0.013). Histological ulceration was associated with the presence of BRAF mutations [odds ratio (OR) 3.141; 95% confidence interval (CI) 1.289-7.655; P = 0.002]. The Breslow index tended to be thicker in BRAF-mutated compared with wild-type (P = 0.086). BRAF mutations were present in 28 (39%) patients and only four cases were positive for NRAS mutations (6%), BRAF and NRAS mutations being mutually exclusive. The presence of dermoscopic peppering was associated with MAPK mutations (BRAF and NRAS) (OR 1.68; 95% CI 1.089-2.581; P = 0.015). Dermoscopic ulceration was also associated with BRAF mutations excluding acral and facial melanomas (OR 2.64; 95% CI 1.032-6.754)., Conclusions: This study showed a correlation between BRAF and NRAS status and dermoscopic findings of 'peppering' as an expression of regression and melanophages in the dermis, suggesting a morphological consequence of immune behaviour in BRAF-mutated melanomas., (© 2014 British Association of Dermatologists.)

The majority of melanoma mutations are C>T transitions, and most bear UV signatures. However, other process may contribute to the high C>T mutation rate. Okura et al., have demonstrated immunohistochemical evidence of deaminating enzymes, activation-induced cytidine deaminase (AID) and apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3B (APOBEC3B) in melanoma. Both have been implicated in cancer. While further validation is necessary, these findings warrant consideration of a role for deamination in melanomagenesis. Deamination primarily drives C>T transitions. Compared with trunk/extremity melanomas, acral melanomas display a significantly higher percentage of 'spontaneous' and 'AID' mutation signature events suggesting deamination may be particularly important in this subgroup., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Importance: Mutations driving melanoma growth have diagnostic, prognostic, and therapeutic implications. Traditional classification systems do not correlate optimally with underlying melanoma growth-promoting mutations. Our objective was to determine whether unique dermoscopic growth patterns directly correlate with driving mutations., Observations: We evaluated common driving mutations in 4 different dermoscopic patterns (rhomboidal, negative pigmented network, polygonal, and dark homogeneous streaks) of primary cutaneous melanomas; 3 melanomas per pattern were tested. Three of the 4 patterns lacked common mutations in BRAF, NRAS, KIT, GNAQ, and HRAS. One pattern, the dark homogeneous streaks pattern, had unique KIT mutations in the second catalytic domain of KIT in exon 17 for all 3 samples tested. Two tumors with the dark homogeneous streaks pattern turned out to be different primary melanomas from the same patient and had different sequence mutations but had an impact on the same KIT domain., Conclusions and Relevance: While future study is required, these results have multiple implications. (1) The underlying melanoma-driving mutations may give rise to specific dermoscopic growth patterns, (2) BRAF/NRAS mutations in early melanomas may not be as common as previously thought, and (3) patients may be predisposed to developing specific driving mutations giving rise to melanomas or nevi of similar growth patterns.

Melanocytic neoplasms are a diverse group of benign and malignant tumors with variable clinical features. While some models still promote the epidermal melanocyte as the origin of melanocytic neoplasms, clinical findings are inconsistent with this theory for the majority of tumors. Despite advances in naevus and melanoma biology, the location and differentiation status of the cell of origin remains undefined. Germ line genetics, biological state and cellular location of the mutated cell, as well as local environmental factors all likely play a role in the development of melanocytic neoplasms. Herein, we will review potential models for melanocytic neoplasia and discuss research challenges and opportunities., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background/objectives: Dermoscopy aids in clinical decision-making. However, time pressure is a common reason precluding its use. We evaluated the effect of time on lesion recognition and management decisions utilising clinical and dermoscopic images., Method: In all, 100 dermoscopic images were presented to 15 dermatologists with experience in dermoscopy and seven non-experts (dermatology residents). Each lesion was displayed thrice in succession. The dermoscopic image was initially presented for 1 s (t1). The same dermoscopic image was shown again without time constraints (t2) and then a final time with additional images of the clinical context (t3). Participants provided a diagnosis, their level of confidence and biopsy predilection after evaluating each image., Results: For benign lesions, both groups rarely changed their diagnosis. However, an improvement in the number of correct benign diagnoses was observed when the lesion was shown in a clinical context. For malignant lesions, both groups improved when more time and clinical context was given; nevertheless, non-experts were more likely to change the diagnosis towards the correct one as more time was given and tended to perform more biopsies, in particular of benign lesions. Limitations were a small number of participants and an artificial study setting., Conclusion: Dermoscopy uses analytical and non-analytical reasoning approaches. We suggest that non-analytical reasoning is employed when rapid clinical decisions need to be made, especially during the evaluation of benign lesions. We conclude that dermoscopy is relatively rapid and non-time-consuming technique that adds relevant information and guides clinicians towards appropriate management decisions., (© 2012 The Authors. Australasian Journal of Dermatology © 2012 The Australasian College of Dermatologists.)

Melanomas demonstrate chromosomal instability (CIN). In fact, CIN can be used to differentiate melanoma from benign nevi. The exact molecular mechanisms that drive CIN in melanoma have yet to be fully elucidated. Cancer/testis antigens are a unique group of germ cell proteins that are found to be primarily expressed in melanoma as compared to benign nevi. The abnormal expression of these germ cell proteins, normally expected only in the testis and ovaries, in somatic cells may lead to interference with normal cellular pathways. Germ cell proteins that may be particularly critical in CIN are meiosis proteins. Here, we review pathways unique to meiosis with a focus on how the aberrant expression of meiosis proteins in normal mitotic cells "meiomitosis" could impact chromosomal instability in melanoma and other cancers.

Background: Most studies on dermoscopy of acral lesions were conducted in Asian populations. In this study, we analyzed these features in a predominantly Caucasian population., Objective: Estimate the prevalence of dermoscopic features in acral lesions, and assess their level of agreement between observers., Methods: In this retrospective multicenter study, 167 acral lesions (66 melanomas) were evaluated for 13 dermoscopic patterns by 26 physicians, via a secured Internet platform., Results: Parallel furrow pattern, bizarre pattern, and diffuse pigmentation with variable shades of brown had the highest prevalence. The agreement for lesion patterns between physicians was variable. Agreement was dependent on the level of diagnostic difficulty., Conclusion: Lesions with a diameter >1 cm were more likely to be melanoma. We found as well that a benign pattern can be seen in parts of melanomas. For this reason one should evaluate an acral lesion for the presence of malignant patterns first.