Lentigo maligna (LM) is a subtype of cutaneous melanoma in situ that develops on chronically sun-damaged skin in elderly individuals. Its diagnosis and management remain challenging due to its slow progression, frequent occurrence on cosmetically sensitive areas in frail individuals, and tendency for subclinical peripheral extension. Despite its potential for invasive transformation, the natural history of LM remains incompletely understood and evidence-based management strategies for this specific entity remain limited. This work aims to bridge the gap between scarce high-quality evidence and the clinicians' need for practical guidance on LM management by formulating evidence-based and expert consensus-driven recommendations for diagnosis, treatment and follow-up. Under the coordination of the International Dermoscopy Society, a global, multidisciplinary consortium of 53 experts-including dermatologists, dermato-oncologists, dermatologic surgeons, radiologists, radiotherapists, pathologists and epidemiologists-formulated recommendations through structured consensus, informed by a comprehensive review of current scientific evidence and clinical practice standards. Optimal management of LM requires accurate diagnosis and individualized treatment planning. Non-invasive skin imaging techniques, especially dermoscopy and reflectance confocal microscopy, aid in diagnosis, biopsy orientation, lesion delineation and post-treatment monitoring. Multiple partial biopsies help confirm diagnosis and rule out invasion. Complete surgical excision remains the first treatment option. No definitive safety margins can be recommended for standard surgery; margin-controlled techniques are preferable for large or ill-defined lesions. Topical imiquimod and radiotherapy are effective alternatives where surgery is unsuitable. Topical imiquimod is useful as primary, adjuvant or neoadjuvant therapy. Blind destructive methods should be avoided. Close clinical and imaging follow-up is needed. Patient-centred care, shared decision-making, and a multidisciplinary approach are critical for optimal outcomes. These international consensus recommendations summarize current best practices for LM management, offering practical, evidence-informed guidance to clinicians while acknowledging the potential of future research in refining these conclusions.

Narrowband ultraviolet B (NB-UVB) phototherapy is a well-established vitiligo treatment. However, limited data exist on the long-term effects of NB-UVB-induced repigmentation. This study evaluated the long-term durability of repigmentation achieved through NB-UVB phototherapy for up to 1 year in 176 patients with non-segmental vitiligo. Demographic and clinical variables, including age, gender, skin phototype, body site involvement, treatment duration, cumulative radiation dose, and clinically significant repigmentation response, were collected. Clinically significant repigmentation was defined as ≥ 50% repigmentation of vitiligo-affected areas, while a durable response was repigmentation lasting ≥ 6 months post-treatment. Of the 176 patients, 80 (45%) achieved clinically significant repigmentation, with the highest success rates observed in the face and neck region (53%). Among responders, 76 (95%) patients maintained their response for ≥ 6 months post-treatment discontinuation, and 47 (59%) sustained repigmentation for > 72 months. Additionally, ≥ 50% repigmentation, longer treatment duration (> 18 months), and higher cumulative radiation dose (> 356 J/cm²) were associated with a durable repigmentation response. NB-UVB phototherapy provides lasting repigmentation in non-segmental vitiligo, with many patients maintaining results for > 6 years. Clinically significant response post-NB-UVB phototherapy, prolonged treatment duration, and cumulative radiation dose are key factors associated with long-term repigmentation.

Current melanoma prognostic tools have limited clinical use at the bedside, highlighting the need for more effective biomarkers. Dermatoscopy correlates with established prognostic markers obtained through invasive procedures. However, its direct predictive value for metastasis remains unexplored. In this multinational study, 30 dermatologists evaluated 776 dermatoscopic images of melanomas (stage IB and above) for predefined criteria including structures, colors and vessels. Extensive dermatoscopic ulceration and blue-white veil are associated with increased risk of metastasis in the total cohort and reduced recurrence-free survival in early-stage melanomas, while extensive regression is associated with reduced metastasis risk and improved recurrence-free survival. Three predictive models of metastasis: (1) dermatoscopic features only, (2) histopathologic features only, and (3) a combination of both demonstrate comparable prognostic accuracy. Here, we show that dermatoscopy may offer valuable prognostic insights into melanoma’s biological behavior before excision and help guide therapeutic decisions. Prospective validation in future trials is essential. Dermatoscopy is a common method to aid in diagnosis of melanoma, however, its utility in predicting metastasis is not fully known. Here, the authors leverage a cohort of 30 dermatologists to develop models to predict prognosis from dermatoscopic images.

BACKGROUND:There is lack of uniformity in reflectance confocal microscopy (RCM) terminology. OBJECTIVE:To establish expert consensus on a standardized set of RCM terms that describe non-melanocytic lesions (NMLs). METHODS:We invited RCM experts to participate in a Delphi-consensus study. Fifty-nine RCM descriptors were extracted from a previous systematic review on RCM terminology for describing NML. Of these, 35 items were presented as 4 groups of synonymous terms and 24 items as single, nonsynonymous terms. For the first round, an agreement threshold was set at >70%. Participants could also propose new terms. Terms with ≤70% agreement and newly proposed terms were carried over to the next round. For subsequent rounds, agreement threshold was set at >50%. RESULTS:The study was conducted between June 2021 and May 2023. Forty-two of 44 (95%) invited experts participated. Three iterative Delphi rounds were completed, resulting in a consensus list of 36 terms, including 32 synonymous and 4 nonsynonymous terms for describing NML. LIMITATIONS:Only experts were included. We did not evaluate definitions of terms in the study. CONCLUSIONS:We propose a simplified list of RCM terms, vetted by RCM experts, for describing and diagnosing NML. Uniform terminology could benefit clinical practice, research, and education.

Negative pigment network (NPN) is a dermoscopic structure frequently associated with melanoma. Though commonly observed in Spitz naevi (SN) and Spitzoid melanoma (SM), its reflectance confocal microscopy (RCM) correlates have been primarily studied in non-Spitzoid melanocytic neoplasms. This study aimed to identify clinical, dermoscopic, and RCM features associated with dermoscopic NPN in Spitzoid neoplasms and explore its histopathological correlates. We retrospectively analysed clinical, dermoscopic, and RCM images from 128 histopathologically confirmed SN and SM cases diagnosed between 2014 and 2020. Lesions were grouped by presence or absence of dermoscopic NPN, and comparisons were made across clinical, dermoscopic, and RCM features. A subset of 20 cases underwent histopathologic correlation. Of the 128 cases, 96 (74%) were SN and 32 (26%) SM. NPN was present in 58 lesions (45%)-40 SN (42%) and 18 SM (56%). NPN was associated with lesion diameter ≥ 5 mm, presence of shiny white structures, dotted vessels, and inversely associated with diffuse blue-white veil. SMs showed higher frequencies of asymmetry, multicomponent patterns, and extensive NPN. RCM features previously linked to NPN-round or linear surface disruptions, bright suprabasal areas, and broadened interpapillary spaces-were seen in 87% of cases but did not correlate with diagnosis or dermoscopic NPN. Corresponding histologic features included keratin-filled dells, hypergranulosis, and broadened rete ridges or infundibula. RCM correlates of dermoscopic NPN are frequently observed in Spitzoid neoplasms, independent of visible dermoscopic NPN, suggesting perceptibility may depend on contrast within dermoscopic patterns.

Whether dermatoscopy deep features could serve as biomarker for the prediction of melanoma metastasis, remains an underexplored area in medical research. In this cohort of 712 patients from ten centers from 3 different continents, a support vector machine (SVM) classifier, analyzing deep features from dermatoscopic images, demonstrated similar prognostic performance for metastasis, in terms of AUC and true positive rate, to current benchmarks of melanoma staging, namely Breslow thickness and ulceration. Deep features derived from dermatoscopy could predict, at the time of diagnosis, early-stage melanomas with high metastatic potential, tailoring further treatment strategies.

Background: Lentigo maligna (LM) can mimic benign, flat, pigmented lesions and can be challenging to diagnose. Objective: To describe a new dermatoscopic feature termed "perifollicular linear projections (PLP)"as a diagnostic criterion for LM on the face. Methods: Retrospective study on reflectance confocal microscopy and dermatoscopy images of flat facial pigmented lesions originating from 2 databases. PLP were defined as short, linear, pigmented projections emanating from hair follicles. Dermatoscopy readers were blinded to the final histopathologic diagnosis. Results: From 83 consecutive LMs, 21/83 (25.3%) displayed "bulging of hair follicles"on reflectance confocal microscopy and 18 of these 21 (85.7%), displayed PLP on dermatoscopy. From a database of 2873 consecutively imaged and biopsied lesions, 252 flat-pigmented facial lesions were included. PLP was seen in 47/76 melanomas (61.8%), compared with 7/176 lesions (3.9%) with other diagnosis (P \ .001). The sensitivity was 61.8% (95% CI, 49.9%-72.7%), specificity 96.0% (95% CI, 92.9%-98.4%). PLP was independently associated with LM diagnosis on multivariate analysis (OR 26.1 [95% CI, 9.6%-71.0]). Limitations: Retrospective study. Conclusion: PLP is a newly described dermatoscopic criterion that may add specificity and sensitivity to the early diagnosis of LM located on the face. We postulate that PLP constitutes an intermediary step in the LM progression model. ( J Am Acad Dermatol 2024;90:52-7.)

BACKGROUND:A common terminology for diagnosis is critically important for clinical communication, education, research and artificial intelligence. Prevailing lexicons are limited in fully representing skin neoplasms. OBJECTIVES:To achieve expert consensus on diagnostic terms for skin neoplasms and their hierarchical mapping. METHODS:Diagnostic terms were extracted from textbooks, publications and extant diagnostic codes. Terms were hierarchically mapped to super-categories (e.g. 'benign') and cellular/tissue-differentiation categories (e.g. 'melanocytic'), and appended with pertinent-modifiers and synonyms. These terms were evaluated using a modified-Delphi consensus approach. Experts from the International-Skin-Imaging-Collaboration (ISIC) were surveyed on agreement with terms and their hierarchical mapping; they could suggest modifying, deleting or adding terms. Consensus threshold was >75% for the initial rounds and >50% for the final round. RESULTS:Eighteen experts completed all Delphi rounds. Of 379 terms, 356 (94%) reached consensus in round one. Eleven of 226 (5%) benign-category terms, 6/140 (4%) malignant-category terms and 6/13 (46%) indeterminate-category terms did not reach initial agreement. Following three rounds, final consensus consisted of 362 terms mapped to 3 super-categories and 41 cellular/tissue-differentiation categories. CONCLUSIONS:We have created, agreed upon, and made public a taxonomy for skin neoplasms and their hierarchical mapping. Further study will be needed to evaluate the utility and completeness of the lexicon.

Extracellular vesicles (EVs) are important mediators of communication between cells. Here, we reveal a new mode of intercellular communication by melanosomes, large EVs secreted by melanocytes for melanin transport. Unlike small EVs, which are disintegrated within the receiver cell, melanosomes stay intact within them, gain a unique protein signature, and can then be further transferred to another cell as "second-hand" EVs. We show that melanoma-secreted melanosomes passaged through epidermal keratinocytes or dermal fibroblasts can be further engulfed by resident macrophages. This process leads to macrophage polarization into pro-tumor or pro-immune cell infiltration phenotypes. Melanosomes that are transferred through fibroblasts can carry AKT1, which induces VEGF secretion from macrophages in an mTOR-dependent manner, promoting angiogenesis and metastasis in vivo. In melanoma patients, macrophages that are co-localized with AKT1 are correlated with disease aggressiveness, and immunotherapy non-responders are enriched in macrophages containing melanosome markers. Our findings suggest that interactions mediated by second-hand extracellular vesicles contribute to the formation of the metastatic niche, and that blocking the melanosome cues of macrophage diversification could be helpful in halting melanoma progression.

INTRODUCTION:Early detection may lead to reduced morbidity and mortality from melanoma. This study aims to establish guidelines for selecting patients suitable for digital monitoring of skin lesions.METHODS:A literature review was conducted, followed by consensus among experts appointed by the Israeli Dermatology Association.RESULTS:Two effective methods for early melanoma diagnosis were identified: Total-body photography (TBP) and digital dermoscopy. TBP involves capturing clinical images of the entire skin area for long-term monitoring (6-12 months). Digital dermoscopy focuses on close-up images of distinct lesions for short-term monitoring (3-4 months). Various risk factors for melanoma were identified, including genetic and familial factors, as well as demographic and phenotypic characteristics. Based on these risk factors and feasibility of clinical follow-up, a comprehensive list of indications for TBP was developed, categorized into three groups based on the expected level of benefit. Digital dermoscopy surveillance is recommended for patients with flat or slightly raised skin lesions showing dermoscopic features that do not definitively indicate melanoma.DISCUSSION:TBP significantly improves early melanoma detection, enhancing sensitivity and specificity while reducing unnecessary biopsies. However, due to its high cost and limited coverage by the Israeli public health care system, prioritizing patients who would benefit most from TBP is crucial. The compiled list of indications aligns with international recommendations and provides further details within the article.

BackgroundWhen monitoring melanocytic neoplasms, the pattern of change may distinguish nevi from melanoma. Anticipating the growth dynamics of nevi based on their dermoscopic pattern is important to make this distinction.ObjectiveThe primary aim was to examine the association between nevus dermoscopic pattern at baseline and diameter change during long-term monitoring. The secondary aim was to examine the association between nevus dermoscopic pattern at baseline and changes in both dermoscopic pattern and colour during long-term monitoring.MethodsThe study included high-risk adult patients that underwent >= 2 total-body photography (TBP) sessions, with at least 14 years' time gap between first and last sessions. Nevi on the torso, with available dermoscopic images, were included. New and disappearing nevi were defined as nevi not appearing on the first and last TBP, respectively. Nevus diameter and colour were assessed on clinical images of first and last TBP images. Dermoscopic images were analysed for dermoscopic patterns and structures at baseline and follow-up.ResultsIn total, 877 nevi from 101 patients were included. Mean follow-up time between TBPs and between dermoscopic images was 16.7 and 11.5 years, respectively. Most nevi were reticular or structureless at baseline, but new nevi had a higher frequency of peripheral globules and smudgy patterns. Peripheral globules and diffuse negative network patterns as well as regression structures were associated with nevus diameter growth. In total, 30% and 15% of new and existing nevi, respectively, demonstrated dermoscopic pattern change, mainly transforming into reticular and structureless patterns.ConclusionsAmong high-risk patients, nevi showing peripheral globules or negative network are more likely to grow in diameter during long-term monitoring. Most nevi retain their overall dermoscopic pattern and those that change, mostly transform into reticular or structureless patterns.

Summary Background Folliculitis decalvans (FD) is a type of primary neutrophilic cicatricial alopecia often leading to irreversible hair loss. Data on its epidemiology, clinical features, outcomes, and prognostic factors are limited. Objective To evaluate a cohort of patients with FD and identify characteristics of severe disease and prognostic factors which impede remission. Patients and Methods This retrospective cohort study included 192 patients diagnosed with FD and followed for at least six months at a tertiary center between 2010 and 2020. Results There was a diagnostic delay averaging 22.2 (± 29.7) months. Comorbid follicular occlusion disorders were common. Bacterial cultures were positive in 45.6% of the cases, with Staphylococcus (S.) aureus being the most common pathogen. Severe disease was associated with comorbid hidradenitis suppurativa and a positive bacterial culture, particularly S. aureus . 50.7% of patients experienced complete remission: 32% within the first six months of treatment and 18.7% later during follow‐up. Relapses were frequent. Negative prognostic factors for achieving remission included younger age and a positive bacterial culture. Conclusions There is a need for the education of dermatologists to reduce the diagnostic delay. Screening FD patients for comorbid hidradenitis suppurativa and obtaining bacterial cultures is important for treatment planning.

Background Treatment management for congenital melanocytic nevi (CMN) on the face (FCMN) is highly variable and requires a thorough assessment of multiple factors. To date, a systematic review of FCMN treatment is lacking. The purpose of the present study was to elucidate the frequency, variety, and outcomes of treatment modalities for FCMN with different levels of complexity. Methods A comprehensive review of Pubmed, Embase, and Google Scholar databases from 1950 to 2022 was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Articles reporting on FCMN treatment approaches, outcomes, and associated complications were screened and data were extracted according to inclusion criteria. Data were tabulated for thematic analysis of FCMN treatment types, anatomic locations, outcomes, and complications. Results Of the 561 studies retrieved, 34 met inclusion criteria including 19 surgical treatments, 14 nonsurgical treatments, and one combined surgical and nonsurgical treatment study, totaling 356 patients. The majority of treated FCMN were small-to-medium-sized (56%). Facial CMN treated conservatively were mostly located on the cheek (27%) and/or perinasal region (21%), whereas FCMN treated with surgery were primarily located in the periorbital region (44%) and/or the cheek (17%). Across all treatment cohorts, 22% of patients experienced at least one complication, with 12% of complications experienced by patients treated by surgery. Conclusions There is a greater need for standardized FCMN nomenclature that encompasses nevi pattern, dimensions, anatomical coverage, and quantitative measurements of treatment outcome. Future studies should focus on identifying anatomic locations of FCMN that are more prone to complications and determine which treatment approach optimizes outcomes.

INTRODUCTION:Melanocytic nevi present microscopic patterns, which differ in their associated melanoma risk, and can be non-invasively recognized under Reflectance Confocal Microscopy (RCM).AIMS:To train a Generative Adversarial Network (GAN) deep-learning model to produce synthetic images that recapitulate RCM patterns of nevi, enabling reliable classification by human readers and by a Convolutional Neural Network (CNN) computer model.METHODS:A dataset of RCM images of nevi, presenting a uniform pattern, were chosen and classified into one of three patterns - Meshwork, Ring or Clod. Images were used for training a GAN model, which in turn, produced synthetic images recapitulating RCM patterns of nevi. A random sample of synthetic images was classified by two independent human readers and by a CNN model. Human and computer-model classifications were compared.RESULTS:The training set for the GAN model included 1496 RCM images, including 977 images (65.3%) with Meshwork pattern, 261 (17.4%) with Ring and 258 (17.2%) with Clod pattern. The GAN model produced 6000 synthetic RCM-like images. Of these, 302 images were randomly chosen and classified by human readers, including 83 (27.5%) classified as Meshwork, 131 (43.4%) as Ring, and 88 (29.1%) as Clod pattern. Human inter-observer concordance in pattern classification was 91.7%, and human-to-CNN concordance was 87.7%.CONCLUSIONS:We demonstrate feasibility of producing synthetic images, which recapitulate RCM patterns of nevi and can be reproducibly recognized by human readers and by deep-learning models. Synthetic image datasets may allow teaching RCM patterns to novices, training of computer models, and data sharing between research centers.

Dermoscopy aids in melanoma detection; however, agreement on dermoscopic features, including those of high clinical relevance, remains poor. In this study, we attempted to evaluate agreement among experts on exemplar images not only for the presence of melanocytic-specific features but also for spatial localization. This was a cross-sectional, multicenter, observational study. Dermoscopy images exhibiting at least 1 of 31 melanocytic-specific features were submitted by 25 world experts as exemplars. Using a web-based platform that allows for image markup of specific contrast-defined regions (superpixels), 20 expert readers annotated 248 dermoscopic images in collections of 62 images. Each collection was reviewed by five independent readers. A total of 4,507 feature observations were performed. Good-to-excellent agreement was found for 14 of 31 features (45.2%), with eight achieving excellent agreement (Gwet's AC >0.75) and seven of them being melanomaspecific features. These features were peppering/granularity (0.91), shiny white streaks (0.89), typical pigment network (0.83), blotch irregular (0.82), negative network (0.81), irregular globules (0.78), dotted vessels (0.77), and blue-whitish veil (0.76). By utilizing an exemplar dataset, a good-to-excellent agreement was found for 14 features that have previously been shown useful in discriminating nevi from melanoma. All images are public (www.isic-archive.com) and can be used for education, scientific communication, and machine learning experiments.

1 Department of Dermatology, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile 2 Department of Pathology, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile 3 The Kittner Skin Cancer Screening & Research Institute, Sheba Medical Center, Ramat Gan, Israel 4 Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel 5 Department of Dermatology, University of Modena and Reggio Emilia, Modena, Italy 6 Centro Oncologico ad Alta Tecnologia Diagnostica-Dermatologia, Arcispedale Santa Maria Nuova, Azienda Unità Sanitaria Locale IRCCS Reggio Emilia, Reggio Emilia, Italy 7 Melanoma and Skin Cancer Unit, Escuela de Medicina, Pontificia Universidad Catolica de Chile, Santiago, Chile

Zusammenfassung Hintergrund Folliculitis decalvans (FD) ist eine primäre neutrophile vernarbende Alopezie, die häufig zu irreversiblem Haarverlust führt. Daten zu Epidemiologie, klinischen Merkmalen, Folgen und prognostischen Faktoren sind nur eingeschränkt verfügbar. Ziel Die Beurteilung einer Patientenkohorte mit FD sowie die Charakterisierung schwerer Krankheitsverläufe und prognostischer Faktoren, die eine Remission verhindern. Patienten und Methoden Diese retrospektive Kohortenstudie umfasste 192 Patienten, bei denen zwischen 2010 und 2020 an einem tertiären Zentrum eine FD diagnostiziert und die mindestens sechs Monate nachverfolgt wurden. Ergebnisse Die Diagnose wurde im Mittel um 22,2 (± 29,7) Monate verzögert gestellt. Komorbide Erkrankungen mit Okklusion der Haarfollikel waren häufig. In 45,6% der Fälle waren Bakterienkulturen positiv, am häufigsten mit Staphylococcus (S.) aureus . Schwere Krankheitsverläufe waren mit komorbider Hidradenitis suppurativa und positiver Bakterienkultur, insbesondere S. aureus , assoziiert. Bei 50,7% der Patienten kam es zu vollständiger Remission: Bei 32% innerhalb der ersten sechs Monate der Behandlung und bei 18,7% während der Nachkontrolle. Rezidive waren häufig. Negative Prognosefaktoren bezüglich der Remission waren jüngeres Alter und positive Bakterienkultur. Schlussfolgerungen Es besteht Bedarf hinsichtlich der Ausbildung von Dermatologen, um die Diagnoseverzögerung zu reduzieren. Das Screening von FD‐Patienten auf komorbide Hidradenitis suppurativa und Bakterienkulturen sind wichtig für die Behandlungsplanung.