Operational classification of cutaneous squamous cell carcinomas based on unsupervised clustering of real cases by experts.

BACKGROUND: There is currently no staging system for cutaneous squamous cell carcinoma (cSCC) that is adapted to decision-making and universally used. Experts have unconscious ability to simplify the heterogeneity of clinical situations into a few relevant groups to drive their therapeutic decisions. Therefore, we have used unsupervised clustering of real cases by experts to generate an operational classification of cSCCs, an approach that was successful for basal cell carcinomas. OBJECTIVE: To generate a consensual and operational classification of cSCCs. METHOD: Unsupervised independent clustering of 248 cases of cSCCs considered difficult-to-treat. Eighteen international experts from different specialties classified these cases into what they considered homogeneous clusters useful for management, each with freedom regarding clustering criteria. Convergences and divergences between clustering were analysed using a similarity matrix, the K-mean approach and the average silhouette method. Mathematical modelling was used to look for the best consensual clustering. The operability of the derived classification was validated on 23 new practitioners. RESULTS: Despite the high heterogeneity of the clinical cases, a mathematical consensus was observed. It was best represented by a partition into five clusters, which appeared a posteriori to describe different clinical scenarios. Applicability of this classification was shown by a good concordance (94%) in the allocation of cases between the new practitioners and the 18 experts. An additional group of easy-to-treat cSCC was included, resulting in a six-group final classification: easy-to-treat/complex to treat due to tumour and/or patient characteristics/multiple/locally advanced/regional disease/visceral metastases. CONCLUSION: Given the methodology based on the convergence of unguided intuitive clustering of cases by experts, this new classification is relevant for clinical practice. It does not compete with staging systems, but they may complement each other, whether the objective is to select the best therapeutic approach in tumour boards or to design homogeneous groups for trials.

Guidelines for the diagnosis and treatment of cutaneous squamous cell carcinoma: a GRADE approach for evidence evaluation and recommendations by the Italian Association of Medical Oncology.

Cutaneous squamous cell carcinoma (CSCC) accounts for ∼20%-25% of all skin tumors. Its precise incidence is often challenging to determine due to limited statistics and its incorporation with mucosal forms. While most cases have a favorable prognosis, challenges arise in patients presenting with locally advanced or metastatic forms, mainly appearing in immunocompromised patients, solid organ transplantation recipients, or those facing social difficulties. Traditionally, chemotherapy and targeted therapy were the mainstays for advanced cases, but recent approvals of immunotherapeutic agents like cemiplimab and pembrolizumab have revolutionized treatment options. These guidelines, developed by the Italian Association of Medical Oncologists (AIOM) using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) approach, aim to guide clinicians in diagnosing, treating, and monitoring patients with CSCC, covering key aspects from primitive tumors to advanced stages, selected by a panel of experts selected by AIOM and other national scientific societies. The incorporation of these guidelines into clinical practice is expected to enhance patient care and address the evolving landscape of CSCC management.

Guidelines for the diagnosis and treatment of basal cell carcinoma: a GRADE approach for evidence evaluation and recommendations by the Italian Association of Medical Oncology.

Basal cell carcinoma (BCC) is the most common form of cancer, with a high impact on the public health burden and social costs. Despite the overall prognosis for patients with BCC being excellent, if lesions are allowed to progress, or in a small subset of cases harboring an intrinsically aggressive biological behavior, it can result in local spread and significant morbidity, and conventional treatments (surgery and radiotherapy) may be challenging. When a BCC is not amenable to either surgery or radiotherapy with a reasonable curative intent, or when metastatic spread occurs, systemic treatments with Hedgehog inhibitors are available. These guidelines were developed, applying the GRADE approach, on behalf of the Italian Association of Medical Oncologists (AIOM) to assist clinicians in treating patients with BCC. They contain recommendations with regard to the diagnosis, treatment and follow-up, from primitive tumors to those locally advanced or metastatic, addressing the aspects of BCC management considered as priorities by a panel of experts selected by AIOM and other national scientific societies. The use of these guidelines in everyday clinical practice should improve patient care.

Long-pulsed Nd:YAG laser using an "in motion" setting to treat telangiectatic rosacea.

BACKGROUND: Rosacea is an inflammatory condition of the face characterized in its early stages by flushing, erythema and telangiectasias. OBJECTIVES: We evaluate the efficacy of long-pulsed Nd:YAG laser on erythematousteleangiectasic rosacea (ETR). METHODS: In a retrospective case study of 21 patients (14F, 7M) with an average age of 29 years (range 19-41), were treated with two sessions at a distance of one month, with phototype up to III (5 phototype 1, 14 phototype II, 2 phototype III) with a fluence of 20 J/cm2. RESULTS: We observed a reduction of the erythematous component between 50% and 80% after two sessions, with an average pain score attributed to the treatment, measured by visual analogue scale (VAS), of 3. CONCLUSION: In this case series in which Nd:YAG laser had been used with a "'in motion" technique, we observed a reduction of the side effects and pain.

Dupilumab ocular side effects in patients with atopic dermatitis: a systematic review.

Atopic dermatitis (AD) is a chronic, inflammatory skin disorder that most frequently occurs in children, but it can also affect adults. Even though most AD cases can be managed with topical treatments, moderate-to-severe forms require systemic therapies. Dupilumab is the first human monoclonal antibody approved for the treatment of AD. Its action is through IL-4 receptor alpha subunit inhibition, thus blocking IL-4 and IL-13 signaling pathways. It has been shown to be an effective, well-tolerated therapy for AD, as well as for asthma, chronic rhinosinusitis with nasal polyposis (CRSwNP), and eosinophilic esophagitis (EoE). However, an increasing incidence of dupilumab-induced ocular surface disease (DIOSD) has been reported in patients treated with dupilumab, as compared to placebo. The aim of this study was to summarize scientific data regarding DIOSD in AD patients treated with dupilumab. A search of PubMed and clinicaltrials.gov databases was performed. There was no limit to study design. All AD cases were moderate-to-severe. DIOSD was either dermatologist-, allergist-, or ophthalmologist-assessed. Evidence shows that DIOSD occurs most frequently in patients with atopic dermatitis and not in other skin conditions, neither in patients with asthma, CRSwNP, nor EoE who are on dupilumab treatment. Further studies are warranted in order to establish a causal relationship between dupilumab and ocular surface disease. Nevertheless, ophthalmological evaluations prior to dupilumab initiation can benefit AD patients with previous ocular pathology or current ocular symptomatology. Also, patch testing for ocular allergic contact dermatitis might be advantageous in patients with a history of allergic conjunctivitis. Furthermore, TARC, IgE, and circulating eosinophils levels might be important biomarkers for a baseline assessment of future candidates to dupilumab treatment. However, TARC measurements should be resumed for research purposes only.

Position statement on classification of basal cell carcinomas. Part 2: EADO proposal for new operational staging system adapted to basal cell carcinomas.

BACKGROUND: No simple staging system has emerged for basal cell carcinomas (BCCs), since they do not follow the TNM process, and practitioners failed to agree on simple clinical or pathological criteria as a basis for a classification. Operational classification of BCCs is required for decision-making, trials and guidelines. Unsupervised clustering of real cases of difficult-to-treat BCCs (DTT-BCCs; part 1) has demonstrated that experts could blindly agree on a five groups classification of DTT-BCCs based on five patterns of clinical situations. OBJECTIVE: Using this five patterns to generate an operational and comprehensive classification of BCCs. METHOD: Testing practitioner's agreement, when using the five patterns classification to ensure that it is robust enough to be used in the practice. Generating the first version of a staging system of BCCs based on pattern recognition. RESULTS: Sixty-two physicians, including 48 practitioners and the 14 experts who participated in the generation of the five different patterns of DTT-BCCs, agreed on 90% of cases when classifying 199 DTT-BCCs cases using the five patterns classification (part 1) attesting that this classification is understandable and usable in practice. In order to cover the whole field of BCCs, these five groups of DTT-BCCs were added a group representing the huge number of easy-to-treat BCCs, for which sub-classification has little interest, and a group of very rare metastatic cases, resulting in a four-stage and seven-substage staging system of BCCs. CONCLUSION: A practical classification adapted to the specificities of BCCs is proposed. It is the first tumour classification based on pattern recognition of clinical situations, which proves to be consistent and usable. This EADO staging system version 1 will be improved step by step and tested as a decision tool and a prognostic instrument.

Position statement on classification of basal cell carcinomas. Part 1: unsupervised clustering of experts as a way to build an operational classification of advanced basal cell carcinoma based on pattern recognition.

BACKGROUND: No simple classification system has emerged for 'advanced basal cell carcinomas', and more generally for all difficult-to-treat BCCs (DTT-BCCs), due to the heterogeneity of situations, TNM inappropriateness to BCCs, and different approaches of different specialists. OBJECTIVE: To generate an operational classification, using the unconscious ability of experts to simplify the great heterogeneity of the clinical situations into a few relevant groups, which drive their treatment decisions. METHOD: Non-supervised independent and blinded clustering of real clinical cases of DTT-BCCs was used. Fourteen international experts from different specialties independently partitioned 199 patient cases considered 'difficult to treat' into as many clusters they want (≤10), choosing their own criteria for partitioning. Convergences and divergences between the individual partitions were analyzed using the similarity matrix, K-mean approach, and average silhouette method. RESULTS: There was a rather consensual clustering of cases, regardless of the specialty and nationality of the experts. Mathematical analysis showed that consensus between experts was best represented by a partition of DTT-BCCs into five clusters, easily recognized a posteriori as five clear-cut patterns of clinical situations. The concept of 'locally advanced' did not appear consistent between experts. CONCLUSION: Although convergence between experts was not granted, this experiment shows that clinicians dealing with BCCs all tend to work by a similar pattern recognition based on the overall analysis of the situation. This study thus provides the first consensual classification of DTT-BCCs. This experimental approach using mathematical analysis of independent and blinded clustering of cases by experts can probably be applied to many other situations in dermatology and oncology.

Dermoscopic and trichoscopic features of primary cutaneous lymphomas - systematic review.

Dermoscopy and trichoscopy are non-invasive methods used as auxiliary tools in diagnostics of different dermatoses. To date, no systematic review concerning the utility of dermoscopy and trichoscopy in the diagnostics of primary cutaneous lymphomas has been published. The aim of this study was to summarize the current state of knowledge on this topic based on systematic search of PubMed database and related references published before 8th of August 2020. Besides dermoscopic features, type of dermoscope, polarization mode, magnification, number of cases and histopathological correlation were analysed. A total of 34 records were included into the final analysis, evaluating 141 patients diagnosed with primary cutaneous T-cell lymphomas and 70 patients with primary cutaneous B-cell lymphomas. Most of the analysed records evaluated dermoscopic features (n = 206); trichoscopy was analysed in only 5 cases. Structures most commonly observed in classical mycosis fungoides (n = 108) were fine short linear vessels/linear vessels, spermatozoa-like vessels and orange-yellow patchy areas. In folliculotropic mycosis fungoides (n = 12), most frequently observed were comedonal lesions/comedo openings/central keratotic plugs and white halo around hair follicles/perifollicular accentuation. Primary cutaneous marginal zone B-cell lymphoma (n = 42) and primary cutaneous follicle centre lymphoma (n = 20) most commonly presented with salmon-coloured background and fine short/linear irregular/serpentine vessels. For other PCL, with less than 10 cases reported in the analysed records, details have been provided in the article. Most observations analysed in this systematic review rely on findings from case reports/case series (with the level of evidence V) and lack a control group. A few studies provided information concerning technical aspects of dermoscopic/trichoscopic examination. The role of dermoscopy/trichoscopy in diagnostics of cutaneous lymphomas requires further studies, especially in entities where dermoscopic features have been described in only single or a few cases. However, it seems that this practical, accessory tool in future may provide additional clues during clinical assessment.

A multicentre study of naevus-associated melanoma vs. de novo melanoma, tumour thickness and body site differences.

BACKGROUND: Whether melanoma in histological contiguity with a naevus [naevus-associated melanoma (NAM)] is distinctly different from melanoma arising de novo remains unclear. OBJECTIVES: To determine whether the characteristics of de novo melanoma differ from NAM and are not due to naevus obliteration in thicker tumours. METHODS: We conducted a multicentre retrospective study of de novo melanoma and NAM in seven referral centres in Europe, Australia and the USA between 2006 and 2015. RESULTS: In a total of 9474 localized melanomas, de novo melanoma was associated with thicker tumours and body site differences compared with NAM. In the subset of T1 melanomas (n = 5307), similar body site differences were found in multivariate analysis by body site. When compared with NAM, de novo melanoma was more likely to affect older individuals (≥ 70 years) when located on the head/neck [odds ratio (OR) 4·65, 95% confidence interval (CI) 2·55-8·46], the trunk (OR 1·82, 95% CI 1·40-2·36) or the upper extremity (OR 1·69, 95% CI 1·14-2·50), was more likely to affect female patients when located on the lower extremities (OR 1·36, 95% CI 1·03-1·80), and was more likely to be of the nodular melanoma subtype (OR 2·23, 95% CI 1·14-4·35) when located on the trunk. De novo melanoma was less likely to have regression present compared with NAM. CONCLUSIONS: Clinicopathological and body site differences between de novo melanoma and NAM support the divergent pathway model of development. These differences were also found in thin melanomas, suggesting that de novo melanomas are different from NAM and their differences are not due to the obliteration of naevus remnants in thicker tumours.

Sclerodermiform basal cell carcinomas vs. other histotypes: analysis of specific demographic, clinical and dermatoscopic features.

BACKGROUND: Among the various types of basal cell carcinoma, the sclerodermiform variant has a high risk of recurrence and local invasiveness. A systematic description of the dermatoscopic features associated with specific body localization is lacking. OBJECTIVES: To describe the clinical and dermoscopic features of sclerodermiform basal cell carcinoma (BCC) according to localization in the body confronting with superficial and nodular types. METHODS: Clinical and dermoscopic images of sclerodermiform, nodular and superficial BCCs were retrospectively evaluated to study the location in the various body districts, maximum diameter, clinical appearance of the lesion, features of edges and presence or absence of specific dermatoscopic criteria of BCCs. RESULTS: We examined 291 histopathologically proven BCCs showing that in nodular BCCs, classical arborizing vessels were more frequently found in the body macro-area (trunk and limbs; n = 46, 97.9%) than in the head/neck area (n = 43, 82.7%); within sclerodermiform BCCs, short arborizing vessels were found more frequently in the head/neck district (n = 35, 49.3%) than in the body (n = 6, 23.1%; P-value 0.02); within nodular BCCs, multiple blue-grey dots and globules were more frequently found on the trunk (n = 23, 48.9%) than in the head/neck district (n = 12, 23.1%; P-value 0.01). In sclerodermiform BCCs, ulceration was found more frequently in the head/neck district (n = 38, 53.5%) than in the body (n = 4, 15.4%; P-value > 0.01), and in superficial BCCs, ulceration was found more frequently in the head/neck district (n = 5, 38.5%) than in the body (n = 8, 9.8%; P-value 0.02). CONCLUSION: Our study shows that superficial BCC are found frequently in the head/neck district dermoscopically characterized by ulceration and arborizing vessels; nodular BCCs are more frequently found in the body than in the head/neck district, and the dermoscopic pattern is characterized by the combination of three features: (i) classical arborizing vessels, (ii) multiple blue-grey dots and (iii) globules. Instead, sclerodermiform BCC is preferentially located in areas at high-moderate risk of recurrence; if pink-white areas and/or fine arborizing vessels are seen, clinicians should consider this diagnosis. Furthermore, location-specific dermatoscopic criteria have been described.

Dermatoscopy of combined blue nevi: a multicentre study of the International Dermoscopy Society.

BACKGROUND: Combined blue nevi (CBN) may mimic melanoma and are relatively often biopsied for diagnostic reasons. OBJECTIVE: To better characterize CBN and to compare it with melanoma. METHODS: We collected clinical and dermatoscopic images of 111 histologically confirmed CBN and contrasted their dermatoscopic characteristics with 132 partly blue coloured melanomas. Furthermore, we compared the accuracy of human experts using pattern analysis with a computer algorithm based on deep learning. RESULTS: Combined blue nevi are usually flat or slightly elevated and, in comparison with melanoma, more frequent on the head and neck. Dermatoscopically, they are typified by a blue structureless part in combination with either brown clods (n = 52, 46.8%), lines (n = 28, 25.2%) or skin-coloured or brown structureless areas (n = 31, 27.9%). In contrast with melanoma, the blue part of CBN is more often well defined (18.9% vs. 4.5%, P < 0.001) and more often located in the centre (22.5% vs. 5.3%, P < 0.001). Melanomas are more often chaotic (OR: 28.7, 95% CI: 14.8-55.7, P < 0.001), have at least one melanoma clue (OR: 10.8, 95% CI: 5.2-22.2 P < 0.001) in particular white lines (OR: 37.1, 95% CI: 13.4-102.9, P < 0.001). Using simplified pattern analysis (chaos and clues), two raters reached sensitivities of 93.9% (95% CI: 88.4-97.3%) and 92.4% (95% CI: 86.5-96.3%) at corresponding specificities of 59.5% (95% CI: 49.7-68.7%) and 65.8% (95% CI: 56.2-74.5%). The human accuracy with pattern analysis was on par with a state-of-the-art computer algorithm based on deep learning that achieved an area under the curve of (0.92, 95% CI: 0.87-0.96) and a specificity of 85.3% (95% CI: 76.5-91.7%) at a given sensitivity of 83.6% (95% CI: 72.5-91.5%). CONCLUSION: CBN usually lack melanoma clues, in particular white lines. The accuracy of pattern analysis for combined nevi is acceptable, and histopathologic confirmation may not be necessary in exemplary cases.

Development of a core outcome set for cutaneous squamous cell carcinoma trials: identification of core domains and outcomes.

BACKGROUND: The lack of uniformity in the outcomes reported in clinical studies of the treatment of cutaneous squamous cell carcinoma (cSCC) complicates efforts to compare treatment effectiveness across trials. OBJECTIVES: To develop a core outcome set (COS), a minimum set of agreed-upon outcomes to be measured in all clinical trials of a given disease or outcome, for the treatment of cSCC. METHODS: One hundred and nine outcomes were identified via a systematic literature review and interviews with 28 stakeholders. After consolidation of this long list, 55 candidate outcomes were rated by 19 physician and 10 patient stakeholders, in two rounds of Delphi exercises. Outcomes scored 'critically important' (score of 7, 8 or 9) by ≥ 70% of patients and ≥ 70% of physicians were provisionally included. At the consensus meeting, after discussion and voting of 44 international experts and patients, the provisional list was reduced to a final core set, for which consensus was achieved among all meeting participants. RESULTS: A core set of seven outcomes was finalized at the consensus meeting: (i) serious or persistent adverse events, (ii) patient-reported quality of life, (iii) complete response, (iv) partial response, (v) recurrence-free survival, (vi) progression-free survival and (vii) disease-specific survival. CONCLUSIONS: In order to increase the comparability of results across trials and to reduce selective reporting bias, cSCC researchers should consider reporting these core outcomes. Further work needs to be performed to identify the measures that should be reported for each of these outcomes.

The evolving field of Dermato-oncology and the role of dermatologists: Position Paper of the EADO, EADV and Task Forces, EDF, IDS, EBDV-UEMS and EORTC Cutaneous Lymphoma Task Force.

BACKGROUND: The incidence of skin cancers has been increasing steadily over the last decades. Although there have been significant breakthroughs in the management of skin cancers with the introduction of novel diagnostic tools and innovative therapies, skin cancer mortality, morbidity and costs heavily burden the society. OBJECTIVE: Members of the European Association of Dermato-Oncology, European Academy of Dermatology and Venereology, International Dermoscopy Society, European Dermatology Forum, European Board of Dermatovenereology of the European Union of Medical Specialists and EORTC Cutaneous Lymphoma Task Force have joined this effort to emphasize the fundamental role that the specialist in Dermatology-Venereology has in the diagnosis and management of different types of skin cancer. We review the role of dermatologists in the prevention, diagnosis, treatment and follow-up of patients with melanoma, non-melanoma skin cancers and cutaneous lymphomas, and discuss approaches to optimize their involvement in effectively addressing the current needs and priorities of dermato-oncology. DISCUSSION: Dermatologists play a crucial role in virtually all aspects of skin cancer management including the implementation of primary and secondary prevention, the formation of standardized pathways of care for patients, the establishment of specialized skin cancer treatment centres, the coordination of an efficient multidisciplinary team and the setting up of specific follow-up plans for patients. CONCLUSION: Skin cancers represent an important health issue for modern societies. The role of dermatologists is central to improving patient care and outcomes. In view of the emerging diagnostic methods and treatments for early and advanced skin cancer, and considering the increasingly diverse skills, knowledge and expertise needed for managing this heterogeneous group of diseases, dermato-oncology should be considered as a specific subspecialty of Dermatology-Venereology.

Dermatoscopic features of thin (≤2 mm Breslow thickness) vs. thick (>2 mm Breslow thickness) nodular melanoma and predictors of nodular melanoma versus nodular non-melanoma tumours: a multicentric collaborative study by the International Dermoscopy Society.

BACKGROUND: Thin nodular melanoma (NM) often lacks conspicuous melanoma-specific dermatoscopic criteria and escapes clinical detection until it progresses to a thicker and more advanced tumour. OBJECTIVE: To investigate the dermatoscopic morphology of thin (≤2 mm Breslow thickness) vs. thick (>2 mm) NM and to identify dermatoscopic predictors of its differential diagnosis from other nodular tumours. METHODS: Retrospective, morphological case-control study, conducted on behalf of the International Dermoscopy Society. Dermatoscopic images of NM and other nodular tumours from 19 skin cancer centres worldwide were collected and analysed. RESULTS: Overall, 254 tumours were collected (69 NM of Breslow thickness ≤2 mm, 96 NM >2 mm and 89 non-melanoma nodular lesions). Light brown coloration (50.7%) and irregular brown dots/globules (42.0%) were most frequently observed in ≤2 mm NMs. Multivariate analysis revealed that dotted vessels (3.4-fold), white shiny streaks (2.9-fold) and irregular blue structureless area (2.4-fold) were predictors for thinner NM compared to non-melanoma nodular tumours. Overall, irregular blue structureless area (3.4-fold), dotted vessels (4.6-fold) and serpentine vessels (1.9-fold) were predictors of all NM compared to non-melanoma nodular lesions. LIMITATIONS: Absence of a centralized, consensus pathology review and cases selected form tertiary centres maybe not reflecting the broader community. CONCLUSIONS: Our study sheds light into the dermatoscopic morphology of thin NM in comparison to thicker NM and could provide useful clues for its differential diagnosis from other non-melanoma nodular tumours.

[Artificial intelligence and smartphone program applications (Apps) : Relevance for dermatological practice]. / Künstliche Intelligenz und Smartphone-Programm-Applikationen (Apps) : Bedeutung für die dermatologische Praxis.

ADVANTAGES OF ARTIFICIAL INTELLIGENCE (AI): With responsible, safe and successful use of artificial intelligence (AI), possible advantages in the field of dermato-oncology include the following: (1) medical work can focus on skin cancer patients, (2) patients can be more quickly and effectively treated despite the increasing incidence of skin cancer and the decreasing number of actively working dermatologists and (3) users can learn from the AI results. POTENTIAL DISADVANTAGES AND RISKS OF AI USE: (1) Lack of mutual trust can develop due to the decreased patient-physician contact, (2) additional time effort will be necessary to promptly evaluate the AI-classified benign lesions, (3) lack of adequate medical experience to recognize misclassified AI decisions and (4) recontacting a patient in due time in the case of incorrect AI classifications. Still problematic in the use of AI are the medicolegal situation and remuneration. Apps using AI currently cannot provide sufficient assistance based on clinical images of skin cancer. REQUIREMENTS AND POSSIBLE USE OF SMARTPHONE PROGRAM APPLICATIONS: Smartphone program applications (apps) can be implemented responsibly when the image quality is good, the patient's history can be entered easily, transmission of the image and results are assured and medicolegal aspects as well as remuneration are clarified. Apps can be used for disease-specific information material and can optimize patient care by using teledermatology.

The presence of eccentric hyperpigmentation should raise the suspicion of melanoma.

BACKGROUND: Melanocytic lesions with eccentric hyperpigmentation (EH), even though without other dermatoscopic features of melanoma, are often excised. OBJECTIVE: Aiming to understand whether the EH in a pigmented lesion is an accurate criterion of malignancy, we evaluated the capability of two evaluators, with different expertise, to correctly diagnose a melanoma when analysing a given lesion in toto versus a partial analysis, with only the EH or the non-hyperpigmented portion (non-EH) visible. METHODS: Dermatoscopic images of 240 lesions (107 melanomas and 133 nevi) typified by EH were selected. Facial, acral, mucosal lesions and lesions showing clear-cut features of melanoma (except for atypical network) were excluded. Clinical and dermoscopic features (main pattern and numbers of colours) were described for all cases. Each image was split in two through a software so that only the EH or the non-EH was visible. Two blinded evaluators examined three sets of images, two with customized images and one with the non-modified ones: they were asked to give a dichotomous diagnosis (melanoma or nevus) for each image. RESULTS: Melanomas were significantly more frequently typified by colour variegation (3 colours in 44.8% and 4 colours in 41.1% of cases) and atypical network (88.1% in the EH). No significant differences in diagnostic accuracy emerged between the two evaluators. Sensitivity improved in the evaluation of the whole lesions (mean sensitivity 89.7%) in comparison with the evaluation of EH or non-EH alone (72.7-62.6%). Specificity increased when evaluating the EH (54.1%). Positive predictive value (PPV) and likelihood ratio (LR+) of EH resulted 52.3% and 1.4, meaning that in one case out of two with EH is a melanoma. CONCLUSIONS: Lesions with EH are challenging, regardless of dermoscopic experience. The EH is a robust criterion for malignancy, since the evaluation of the whole lesion, through an intralesional comparative approach, increases sensitivity.