The incidence of melanoma and non-melanoma skin cancers (NMSCs) is increasing worldwide. While NMSCs are more common, melanoma remains the most challenging because of its higher aggressiveness. Although the use of sunscreens is key in high-risk populations, it provides limited protection, which highlights the need for alternative solutions. In this review, we discuss current evidence on chemopreventive therapies, as well as their efficacy and adverse events, including immunocompetent and immunosuppressed patients. Acitretin, nicotinamide, 5-fluorouracil, and photodynamic therapy have shown overall promising results in actinic keratosis and squamous cell carcinoma. Nevertheless, more research is needed to establish their efficacy, particularly in melanoma, Merkel cell carcinoma, and cutaneous lymphoma, due to their higher mortality rates.

Background: Line-field confocal optical coherence tomography (LC-OCT) is an innovative non-invasive imaging technique recently introduced in dermatology. Its use has been established particularly in the diagnosis of skin cancer. The LC-OCT description of basal cell carcinoma (BCC) criteria has served for the conduction of retrospective evaluations on its diagnostic performance, which demonstrated its utility in diagnosis and subtyping BCC. However, prospective studies performed at patients' bedside are currently lacking in this field. Objective: The objective of the study was to provide parameters of LC-OCT diagnostic performance for BCC derived from a prospective study performed at patients' bedside. Methods: Lesions clinically equivocal for BCC were prospectively included. Dermoscopic and LC-OCT diagnoses were obtained at the patients' bedside by an expert observer prior to surgical excision or biopsy. Results: A total of 214 lesions (163 BCCs and 51 BCC imitators) belonging to 119 patients were included. For the differentiation of BCC from BCC-imitators, LC-OCT had the same sensitivity as dermoscopy (98%) but a better specificity (90% vs. 37%). For the discrimination of superficial BCC from other BCC subtypes, LC-OCT had an increased sensitivity and specificity compared to dermoscopy (72% vs. 62%, and 97% vs. 84%, respectively). Conclusions: This prospective study showed that the diagnostic performance for BCC diagnosis and subtyping can be remarkedly increased by LC-OCT compared to dermoscopic examination alone. Our data encourages the inclusion of LC-OCT in the diagnostic process and management of equivocal lesions for BCC.

BACKGROUND/OBJECTIVES:Melanoma is the most lethal cutaneous neoplasm, with Breslow thickness being a key prognostic factor. This retrospective cohort study aimed to assess the impact of screening frequency and diagnostic methods on tumour stage at diagnosis and to explore implications for risk-adapted strategies. METHODS:Between 2017 and 2024, 475 cases of melanoma were diagnosed in 397 patients. Screening frequency, diagnostic method, and patient risk were analyzed in relation to tumour stage. RESULTS:Compared with first-visit cases, patients who underwent screening within two years prior to diagnosis were more often diagnosed with melanoma in situ (32.6% vs. 44-51%; p < 0.05) and had thinner invasive tumours (0.68-0.73 mm vs. 1.8 mm; p ≤ 0.001), though no differences were seen between screening frequencies. Full-body examination was associated with more in situ melanomas (46% vs. 34%; p = 0.016) and thinner invasive tumours (0.92 vs. 2.05 mm; p = 0.2) compared with lesion-directed screening, but this effect disappeared after excluding first-visit cases. Invasive melanomas diagnosed by mole mapping were significantly thinner than by dermoscopy (0.55 vs. 1.07; p = 0.035). In high-risk patients, tumour thickness decreased with more frequent visits (0.905 mm without screening vs. 0.40-0.55 mm with ≥1 visit; p = 0.001). Moreover, mole mapping identified thinner melanomas in the high-risk group compared with dermoscopy (0.47 vs. 0.60 mm; p = 0.02). CONCLUSIONS:Screening is associated with thinner melanomas and more in situ diagnoses. Digital mole mapping offers additional benefits, with high-risk patients profiting most, while low-risk individuals could be managed with less resource-intensive approaches. These findings support risk-adapted screening strategies focusing on intensive, digitally supported modalities for high-risk groups.

INTRODUCTION:Numerous imaging techniques, such as reflectance confocal microscopy (RCM), optical coherence tomography (OCT), and line-field confocal OCT (LC-OCT), are available for skin evaluation. However, there remains a need for improved imaging methods to better understand tumor histology and enhance surgical margin detection. This study aimed to evaluate the quality of ex vivo LC-OCT images in cutaneous tumors, describe their morphological features, and correlate the findings with dermoscopy, in vivo RCM, and histology. METHODS:A prospective study was conducted from June 2022 to July 2023, including patients aged ≥18 years with cutaneous tumors on the trunk or limbs. Clinical, dermoscopic, RCM, ex vivo LC-OCT, and histopathological images were collected from 10 tumors, including melanomas, seborrheic keratoses, basal cell carcinomas, and melanocytic nevi. RESULTS:Ex vivo LC-OCT produced high-quality images equivalent to those from in vivo devices, enabling three-dimensional visualization of excised tumors. The images displayed cellular resolution with strong correlations to confocal microscopy and histology. CONCLUSION:Ex vivo LC-OCT shows promise for improving the evaluation of cutaneous tumors and may enhance dermato-oncological surgery, particularly in margin control.

BACKGROUND:Basal cell carcinoma (BCC) is the most common skin cancer, requiring an early diagnosis and accurate margin definition to prevent functional and cosmetic complications. Traditional methods using clinical and dermoscopic images (C&D) often rely on biopsies and histology for final validation. Non-invasive techniques like LC-OCT, enabling 'digital biopsies', are promising alternatives, but remain underutilized due to the expertise required. The development of Artificial Intelligence (AI) algorithms is a promising approach to assist dermatologists in their diagnosis and support the broader adoption of such technologies. OBJECTIVES:We present a real-time AI assistant for BCC diagnosis with LC-OCT, which is, to date, the only real-time AI model across all dermatological imaging modalities. The study aims to quantify the model's effectiveness when used by dermatologists with different levels of expertise and compare its performance with traditional methods and unaided LC-OCT. METHODS:This multicenter, retrospective study involved 43 dermatologists in a double-rounded quiz on 200 equivocal BCC lesions. Diagnoses were first made on C&D images, then with LC-OCT or AI-assisted LC-OCT in a randomized manner. RESULTS:AI-assisted LC-OCT significantly improves dermatologists' diagnostic performance in detecting BCC (+25.8 points in sensitivity and +16.8 points in specificity compared to C&D), particularly benefiting those with less LC-OCT experience, effectively bridging a 2-year gap of expertise. These results highlight the potential for broader clinical adoption through AI assistance and underscore its promise in reducing the need for invasive procedures and improving patient outcomes. CONCLUSIONS:These results support a broader adoption of LC-OCT use in clinical practice thanks to AI assistance and underscore its promise in reducing the need for invasive procedures and improving patient outcomes.

Background: Basal cell carcinoma (BCC) is the most common skin cancer worldwide, with a multifactorial aetiology involving environmental and intrinsic factors. A small subset of patients develops high-frequency BCC (HF-BCC), defined as ≥9 BCCs within 3 years. Objective: To analyse demographic, clinical, and histopathological features of non-syndromic HF-BCC in a Belgian cohort, compared with low-burden BCC patients and healthy controls. Methods: A retrospective cohort study was conducted at Erasme Hospital (Brussels) using data from the EUSCAP platform. Clinical, behavioural, and histopathological data were collected and statistically analysed. Results: Of 783 patients, 16 with HF-BCC were identified. For comparison, 32 patients with 1–2 BCCs and 117 patients without BCC were selected. HF-BCC patients showed distinct characteristics, including a higher proportion of superficial BCCs (68.3% vs. 50%, p = 0.01) and fewer nodular subtypes (43.2% vs. 63.5%, p = 0.01). Their tumours were less frequently located on the nose and ears compared with patients having 1–2 BCCs. HF-BCC was associated with a personal history of squamous cell carcinoma (SCC) and actinic keratosis (AK). Conclusions: HF-BCC patients display distinct anatomical, histopathological and clinical characteristics, with a predominance of superficial BCC and an association with a personal history of SCC and AK. They show a lower frequency of tumours on the nose and ears, with a stronger tendency for localisation on the trunk and extremities. Identifying risk factors and genetic markers may contribute to improved early detection strategies, preventive measures, and the development of targeted therapies.

Introduction Numerous imaging techniques, such as Reflectance Confocal Microscopy (RCM), Optical Coherence Tomography (OCT), and Line-field Confocal OCT (LC-OCT), are available for skin evaluation. However, there remains a need for improved imaging methods to better understand tumor histology and enhance surgical margin detection. This study aimed to evaluate the quality of ex vivo LC-OCT images in cutaneous tumors, describe their morphological features, and correlate the findings with dermoscopy, in vivo RCM, and histology. Methods: A prospective study was conducted from June 2022 to July 2023, including patients aged ≥18 years with cutaneous tumors on the trunk or limbs. Clinical, dermoscopic, RCM, ex vivo LC-OCT, and histopathological images were collected from 10 tumors, including melanomas, seborrheic keratoses, basal cell carcinomas, and melanocytic nevi. Results: Ex vivo LC-OCT produced high-quality images equivalent to those from in vivo devices, enabling three-dimensional visualization of excised tumors. The images displayed cellular resolution with strong correlations to confocal microscopy and histology. Conclusions: Ex vivo LC-OCT shows promise for improving the evaluation of cutaneous tumors and may enhance dermato-oncological surgery, particularly in margin control.

INTRODUCTION:Vascular patterns play a crucial role in the diagnosis and differentiation of skin lesions by providing insight into underlying pathology and aid in distinguishing between benign and malignant lesions. While dermoscopy has proven valuable for visualizing these vascular structures, line-field confocal optical coherence tomography (LC-OCT) offers high-resolution, 3-dimensional (3D) imaging of the skin, potentially providing detailed visualization of vascular architecture and new insights into their projection in dermoscopy. OBJECTIVES:This pilot study aimed to investigate the correlation between vascular patterns in skin lesions with LC-OCT and dermoscopy and explored tridimensional imaging in assessing microvascular architecture. METHODS:A cohort of patients with 14 diverse skin lesions showing typical dermoscopic vascular patterns were examined using dermoscopy and LC-OCT. LC-OCT images were analyzed, and manual segmentation with tridimensional reconstruction of the vascular structures was performed. The correlation between these vascular structures and their dermoscopic projection was then assessed qualitatively. RESULTS:LC-OCT demonstrated a strong visual correlation with dermoscopy in identifying vascular patterns, offering additional depth and 3D details of the intricate relationship between skin micro-architecture and the development of specific vascular patterns in skin lesions. CONCLUSIONS:LC-OCT correlates with dermoscopy in vascular pattern analysis in skin lesions. The added advantage of 3D imaging helped us understand the way vascular structures are formed in skin lesions depending on their micro-architecture. LC-OCT could potentially play a significant role in precisely assessing the vascular environment of skin lesions. Further studies are necessary to assess how this could provide clinical value for diagnosing or monitoring skin lesions.

We report a 73-year-old male presenting with recurrent primary perianal EMPD. The patient declined both surgery and topical imiquimod and preferred cryotherapy among the other available non-invasive therapeutic options. At the 1-month follow-up visit, a complete response to treatment was suspected both on clinical and dermoscopic background and confirmed by LC-OCT examination, that indeed controlled the treatment efficacy by demonstrating the absence of Paget’s cells.For patients seeking less invasive treatment options, LC-OCT-controlled cryotherapy not only reduces invasiveness but also allows for accurate real-time monitoring.

A 73-year-old man presented with recurrent primary perianal extramammary Paget disease. The patient declined both surgery and topical imiquimod and preferred cryotherapy from the other available noninvasive therapeutic options. At the 1-month follow-up visit, a complete response to treatment was suspected both on clinical and dermoscopic examination. This response was confirmed by line-field confocal optical coherence tomography (LC-OCT), which demonstrated the efficacy of the treatment by the absence of Paget cells. For patients seeking less-invasive treatment options, LC-OCT-controlled cryotherapy not only reduces invasiveness but also allows for accurate real-time monitoring.

Introduction: Facial pigmented lesions pose significant challenges for diagnosis and treatment planning due to their anatomical topography and complexity. Traditional methods like dermoscopy have limitations, and while reflectance confocal microscopy (RCM) offers in-vivo cellular resolution, it is hindered by shallow penetration. The recently developed line-field confocal optical coherence tomography (LC-OCT) combines the benefits of OCT and RCM, providing deeper penetration and three-dimensional cellular imaging. Objectives: This study aims to assess the ability of LC-OCT in displaying morphological features correlated and compared with RCM and histopathological findings. Methods: Over a period of 1 year, various pigmented facial lesions were selected, including solar lentigo, seborrheic keratosis, lichen planus-like keratosis, pigmented actinic keratosis, basal cell carcinoma, compound nevus, lentigo maligna, and invasive melanoma. LC-OCT and RCM were used for imaging, and their morphological features were compared. Lesions, except solar lentigo and compound nevus, were excised for histopathological evaluation. Morphological criteria from imaging were correlated with histopathological findings. Results: LC-OCT matched RCM in spatial resolution while providing deeper tissue penetration and three-dimensional visualization. This advantage was particularly notable in pigmented actinic keratosis and basal cell carcinoma, where LC-OCT’s vertical imaging offered unique diagnostic insights. It also enhanced the understanding of the architecture of melanocytic lesions. Conclusion: LC-OCT adds new insight into the imaging and diagnosis of facial pigmented lesions, offering additional morphological features. This pilot study highlights its potential to improve diagnostic accuracy and patient care, with further research needed to assess its broader clinical applications.

Background: The accurate diagnosis of facial pigmented lesions is crucial due to their potential for malignancy and significant cosmetic concerns. This study aims to evaluate the effectiveness of line-field confocal optical coherence tomography (LC-OCT) in the morphological assessment of facial pigmented lesions and its correlation with reflectance confocal microscopy (RCM), thereby enhancing diagnostic accuracy and management strategies. Methods: Adult patients with clinically equivocal facial and scalp pigmented lesions were prospectively assessed using LC-OCT and RCM. Lesions included seborrheic keratosis, lichen-planus like keratosis, pigmented actinic keratosis, pigmented compound nevus, lentigo maligna, and invasive melanoma, with solar lentigo as a comparative entity. Images were analyzed for morphologic criteria and diagnostic performance, correlating LC-OCT findings with RCM and histopathological outcomes where applicable. Results: LC-OCT demonstrated high-resolution, tridimensional images that closely correlated with RCM findings, providing valuable insights into the micro-architectural and cytological aspects of lesions. For instance, solar lentigo revealed a regular honeycomb pattern and elongated rete ridges on both LC-OCT and RCM, while lentigo maligna and invasive melanoma presented atypical dendritic cells in the epidermis with follicular involvement. LC-OCT's vertical and tridimensional imaging capabilities offered enhanced visualization of the lesions' architecture and depth, providing easily-recognizable histopathology-like features. Conclusions: LC-OCT, with its ability to generate high-resolution, tridimensional images, complements RCM in the assessment of facial pigmented lesions, potentially offering enhanced diagnostic accuracy and potential for better management decisions. The technology's depth penetration and visualization capabilities highlight its value in dermatological practice, particularly for lesions where detailed architectural analysis is essential. This study underscores the utility of LC-OCT in the evolving landscape of dermatological imaging, warranting further research to establish its role in clinical practice.

IntroductionLine-field confocal optical coherence tomography (LC-OCT) represents one of the newest non-invasive in vivo skin imaging techniques. Previous studies described morphologic criteria of basal cell carcinoma (BCC) under LC-OCT examination. Preliminary data on LC-OCT diagnostic performance for BCC have recently been published but showed only a modest improvement compared to dermoscopy, possibly due to study limitations.ObjectivesThe main objective of this study was to find diagnostic performance parameters of LC-OCT for differentiating BCC from its clinical/dermoscopic mimickers and for discriminating among BCC subtypes. An additional objective was to suggest a simple, user-friendly diagnostic algorithm based on the most powerful LC-OCT features in the field of BCC and its imitators.Materials and MethodsEquivocal BCC lesions imaged with an LC-OCT device prior to biopsy/excision were included. Three observers blinded for histopathological diagnosis retrospectively formulated clinical, dermoscopic and LC-OCT diagnoses and evaluated LC-OCT features for each study lesion.ResultsA total of 303 lesions (173 BCCs and 130 non-BCCs) from 225 patients were included. For the differentiation of BCC from BCC imitators, the use of LC-OCT increased the diagnostic accuracy compared to clinical examination by 24% and compared to dermoscopy by 12%. For the discrimination of sBCC from other BCC subtypes, LC-OCT increased the diagnostic accuracy compared to clinical examination by 18% and compared to dermoscopy by 12%. The presence of lobule with millefeuille pattern was a significant feature for BCC diagnosis. Lobule shape and location allowed BCC subtype discrimination.ConclusionsThe accuracy of BCC diagnosis can be increased by at least 12% with the use of LC-OCT compared to clinical and dermoscopic examinations alone, both in terms of BCC differentiation from clinical/dermoscopic imitators and in terms of BCC-subtype discrimination. A diagnostic algorithm based on significant features for BCC diagnosis is proposed, for which further validation is required.

Journal of the European Academy of Dermatology and VenereologyAccepted Articles LETTER TO THE EDITORFull Access Dermoscopic criteria explained by LC-OCT: negative maple leaf like areas Gerardo Palmisano, Gerardo Palmisano orcid.org/0009-0000-9681-1681 Department of Dermatology, Hôpital Erasme, HUB, Université Libre de Bruxelles, Brussels, Belgium Department of Dermatology, Catholic University of the Sacred Heart, Rome, Italy The first two authors contributed equally.Search for more papers by this authorCarmen Orte Cano, Carmen Orte Cano orcid.org/0000-0002-1570-7856 Department of Dermatology, Hôpital Erasme, HUB, Université Libre de Bruxelles, Brussels, Belgium Department of Dermato-Oncology, Institut Jules Bordet, HUB, Université Libre de Bruxelles, Brussels, Belgium The first two authors contributed equally.Search for more papers by this authorMargot Fontaine, Margot Fontaine Department of Dermatology, Hôpital Erasme, HUB, Université Libre de Bruxelles, Brussels, Belgium Department of Dermato-Oncology, Institut Jules Bordet, HUB, Université Libre de Bruxelles, Brussels, BelgiumSearch for more papers by this authorClément Lenoir, Clément Lenoir Department of Dermatology, Hôpital Erasme, HUB, Université Libre de Bruxelles, Brussels, Belgium Department of Dermato-Oncology, Institut Jules Bordet, HUB, Université Libre de Bruxelles, Brussels, BelgiumSearch for more papers by this authorElisa Cinotti, Elisa Cinotti orcid.org/0000-0002-4009-0659 Groupe d'Imagerie Cutanée Non Invasive (GICNI) of the Société Française de Dermatologie (SFD), Paris, France Dermatology Unit, Department of Medical, Surgical and Neurological Sciences, University of Siena, Siena, ItalySearch for more papers by this authorLinda Tognetti, Linda Tognetti orcid.org/0000-0002-6691-4310 Dermatology Unit, Department of Medical, Surgical and Neurological Sciences, University of Siena, Siena, ItalySearch for more papers by this authorPietro Rubegni, Pietro Rubegni Dermatology Unit, Department of Medical, Surgical and Neurological Sciences, University of Siena, Siena, ItalySearch for more papers by this authorJaviera Perez-Anker, Javiera Perez-Anker orcid.org/0000-0002-6959-7250 Melanoma Unit, Hospital Clinic Barcelona, University of Barcelona, Barcelona, Spain CIBER de enfermedades raras, Instituto de Salud Carlos III, Barcelona, SpainSearch for more papers by this authorSusana Puig, Susana Puig orcid.org/0000-0003-1337-9745 Melanoma Unit, Hospital Clinic Barcelona, University of Barcelona, Barcelona, Spain CIBER de enfermedades raras, Instituto de Salud Carlos III, Barcelona, SpainSearch for more papers by this authorJosep Malvehy, Josep Malvehy Melanoma Unit, Hospital Clinic Barcelona, University of Barcelona, Barcelona, Spain CIBER de enfermedades raras, Instituto de Salud Carlos III, Barcelona, SpainSearch for more papers by this authorJean-Luc Perrot, Jean-Luc Perrot Department of Dermatology, University Hospital of Saint-Etienne, Saint-Etienne, FranceSearch for more papers by this authorVéronique del Marmol, Véronique del Marmol Department of Dermatology, Hôpital Erasme, HUB, Université Libre de Bruxelles, Brussels, BelgiumSearch for more papers by this authorKetty Peris, Ketty Peris orcid.org/0000-0003-1957-6600 Department of Dermatology, Catholic University of the Sacred Heart, Rome, Italy UOC di Dermatologia, Dipartimento di Scienze Mediche e Chirurgiche Addominali ed Endocrino-Metaboliche, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, ItalySearch for more papers by this authorMariano Suppa, Corresponding Author Mariano Suppa [email protected] orcid.org/0000-0002-9266-0342 Department of Dermatology, Hôpital Erasme, HUB, Université Libre de Bruxelles, Brussels, Belgium Department of Dermato-Oncology, Institut Jules Bordet, HUB, Université Libre de Bruxelles, Brussels, Belgium Groupe d'Imagerie Cutanée Non Invasive (GICNI) of the Société Française de Dermatologie (SFD), Paris, France Correspondence Mariano Suppa, MD, PhD, Department of Dermatology, Hôpital Erasme, HUB, Université Libre de Bruxelles, 808 Route de Lennik, 1070 Brussels, Belgium, Tel: +32 2 555 46 12, Email: [email protected]Search for more papers by this author Gerardo Palmisano, Gerardo Palmisano orcid.org/0009-0000-9681-1681 Department of Dermatology, Hôpital Erasme, HUB, Université Libre de Bruxelles, Brussels, Belgium Department of Dermatology, Catholic University of the Sacred Heart, Rome, Italy The first two authors contributed equally.Search for more papers by this authorCarmen Orte Cano, Carmen Orte Cano orcid.org/0000-0002-1570-7856 Department of Dermatology, Hôpital Erasme, HUB, Université Libre de Bruxelles, Brussels, Belgium Department of Dermato-Oncology, Institut Jules Bordet, HUB, Université Libre de Bruxelles, Brussels, Belgium The first two authors contributed equally.Search for more papers by this authorMargot Fontaine, Margot Fontaine Department of Dermatology, Hôpital Erasme, HUB, Université Libre de Bruxelles, Brussels, Belgium Department of Dermato-Oncology, Institut Jules Bordet, HUB, Université Libre de Bruxelles, Brussels, BelgiumSearch for more papers by this authorClément Lenoir, Clément Lenoir Department of Dermatology, Hôpital Erasme, HUB, Université Libre de Bruxelles, Brussels, Belgium Department of Dermato-Oncology, Institut Jules Bordet, HUB, Université Libre de Bruxelles, Brussels, BelgiumSearch for more papers by this authorElisa Cinotti, Elisa Cinotti orcid.org/0000-0002-4009-0659 Groupe d'Imagerie Cutanée Non Invasive (GICNI) of the Société Française de Dermatologie (SFD), Paris, France Dermatology Unit, Department of Medical, Surgical and Neurological Sciences, University of Siena, Siena, ItalySearch for more papers by this authorLinda Tognetti, Linda Tognetti orcid.org/0000-0002-6691-4310 Dermatology Unit, Department of Medical, Surgical and Neurological Sciences, University of Siena, Siena, ItalySearch for more papers by this authorPietro Rubegni, Pietro Rubegni Dermatology Unit, Department of Medical, Surgical and Neurological Sciences, University of Siena, Siena, ItalySearch for more papers by this authorJaviera Perez-Anker, Javiera Perez-Anker orcid.org/0000-0002-6959-7250 Melanoma Unit, Hospital Clinic Barcelona, University of Barcelona, Barcelona, Spain CIBER de enfermedades raras, Instituto de Salud Carlos III, Barcelona, SpainSearch for more papers by this authorSusana Puig, Susana Puig orcid.org/0000-0003-1337-9745 Melanoma Unit, Hospital Clinic Barcelona, University of Barcelona, Barcelona, Spain CIBER de enfermedades raras, Instituto de Salud Carlos III, Barcelona, SpainSearch for more papers by this authorJosep Malvehy, Josep Malvehy Melanoma Unit, Hospital Clinic Barcelona, University of Barcelona, Barcelona, Spain CIBER de enfermedades raras, Instituto de Salud Carlos III, Barcelona, SpainSearch for more papers by this authorJean-Luc Perrot, Jean-Luc Perrot Department of Dermatology, University Hospital of Saint-Etienne, Saint-Etienne, FranceSearch for more papers by this authorVéronique del Marmol, Véronique del Marmol Department of Dermatology, Hôpital Erasme, HUB, Université Libre de Bruxelles, Brussels, BelgiumSearch for more papers by this authorKetty Peris, Ketty Peris orcid.org/0000-0003-1957-6600 Department of Dermatology, Catholic University of the Sacred Heart, Rome, Italy UOC di Dermatologia, Dipartimento di Scienze Mediche e Chirurgiche Addominali ed Endocrino-Metaboliche, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, ItalySearch for more papers by this authorMariano Suppa, Corresponding Author Mariano Suppa [email protected] orcid.org/0000-0002-9266-0342 Department of Dermatology, Hôpital Erasme, HUB, Université Libre de Bruxelles, Brussels, Belgium Department of Dermato-Oncology, Institut Jules Bordet, HUB, Université Libre de Bruxelles, Brussels, Belgium Groupe d'Imagerie Cutanée Non Invasive (GICNI) of the Société Française de Dermatologie (SFD), Paris, France Correspondence Mariano Suppa, MD, PhD, Department of Dermatology, Hôpital Erasme, HUB, Université Libre de Bruxelles, 808 Route de Lennik, 1070 Brussels, Belgium, Tel: +32 2 555 46 12, Email: [email protected]Search for more papers by this author First published: 25 October 2023 https://doi.org/10.1111/jdv.19588 This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi:10.1111/jdv.19588. AboutPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Accepted ArticlesAccepted, unedited articles published online and citable. The final edited and typeset version of record will appear in the future. RelatedInformation

Background: Atypical fibroxanthoma (AFX) is a rare mesenchymal skin tumor that typically presents as solitary, rapid-growing, dome-shaped nodules, which can be clinically and dermoscopically difficult to distinguish from other non-pigmented skin lesions. We report a histopathologically confirmed case of atypical fibroxanthoma (AFX) and the first description of its features in Line-Field Confocal Optical Coherence Tomography (LC-OCT) and we compared it with Reflectance Confocal Microscopy (RCM). Methods: A 70-year-old female patient presented with rapidly growing suspected recurrence of a histologically confirmed AFX in the left ear canal. The lesion was evaluated using Line-field LC-OCT and RCM to characterize its morphological features. Comprehensive imaging analysis relied on identifying specific morphologic criteria associated with this pathology based on established literature in histopathology and the few existing reports of AFX examined with RCM. The acquisitions from these two imaging techniques were then morphologically compared. Results: LC-OCT provided high-resolution, horizontal and vertical images as well as tridimensional reconstructions of the nodular lesion. It showed a proliferation of large hyporeflective roundish cells among a very dense dermal matrix characterized by thick, elongated and disorganized collagen fibers. RCM examination revealed the same stretched and thick collagen fibers intertwined around large roundish cells in the dermis but with less penetration depth and finer contrast in the horizontal plane than in LC-OCT. The normal epidermis was clearly identified by a regular honeycomb pattern on both imaging modalities. No sign of other possible neoplasm like fast-growing basal cell and spinal cell carcinoma or melanoma were observed in either techniques. Conclusions: The recent introduction of LC-OCT as a non-invasive diagnostic tool after the emergence of RCM represents a significant advancement in dermatologic oncology and has already been proven valuable for the management of frequent and less frequent skin lesions. LC-OCT has the advantage of providing vertical and tridimensional visualization with similar resolution as RCM but deeper penetration, potentially valuable in the case of dermal lesions like AFX. Further reports and performance studies are required to assess the accuracy of these new techniques in such tumors.

UVA-UVB increases skin matrix metalloproteinases and breaks down extracellular proteins and fibrillar type 1 collagen, leading to photodamage. Topical application of nicotinamide prevents UV-induced immunosuppression. Several studies have demonstrated the importance of protection against UV. This study aims to determine the biological effect of a high broad-spectrum UVB-UVA sunscreen containing nicotinamide and panthenol (SSNP) on photodamaged skin using linear confocal optical coherence tomography (LC-OCT), immunohistochemistry, and RNA profiling. Two areas of severely photodamaged forearm skin (L01 and L02) and one less sun-damaged (naturally protected) area on the inner part of the forearm (L03) were identified in 14 subjects. These areas were imaged using LC-OCT and L01 and L03 were biopsied at baseline. After 4 weeks of treatment with SSNP, L02 was reimaged using LC-OCT, and biopsied. Histology, immunostaining with p21, p53, PCNA, and CPD, and RNA sequencing were performed in all samples. LC-OCT analysis showed that epidermis thickness and the number of keratinocytes is higher in the sun-exposed areas than in the non-exposed areas. Comparing before and after treatment, even though there is a trend towards normalization, the differences were not statistically significant. The expression of p21, PCNA, p53, and CPD increased in severely photodamaged skin compared to less-damaged skin. When comparing before and after treatment, only p21 showed a trend to decrease expression. RNA sequencing analysis identified 1552 significant genes correlating with the progression from non-visibly photodamaged skin to post-treatment and pre-treatment samples; in the analysis comparing pre- and post-treatment samples, 5429 genes were found to be significantly associated. A total of 1115 genes are common in these two analyses. Additionally, nine significant genes from the first analysis and eight from the second are related to collagen. Six of these collagen genes are common in the two analyses. MAPK and cGMP-PKG signalling pathways are upregulated in the progression to photodamage analysis. In the pre- and post-treatment analysis, 32 pathways are downregulated after treatment, the most statistically significant being the ErbB, Hippo, NOD-like receptor, TNF, and NF-kB signalling pathways. This study demonstrates the role of SSNP in collagen generation, highlights the relevance of the cGMP-PKG and MAPK signalling pathways in photodamage, and shows the ability of SSNP to downregulate pathways activated by UV exposure. Additionally, it deepens our understanding of the effect of SSNP on immune-related pathways. This study focuses on the damage that sun exposure can do to our skin, also called photodamage. This damage is mainly caused by ultraviolet radiation, which can lead to problems such as wrinkles, changes in skin color, and sagging skin. Nicotinamide, a form of vitamin B3, helps our cells repair their DNA and prevents them from dying. Previous studies in mice have shown that nicotinamide can protect the immune system against photodamage and reduce the risk of cancer. In order to understand how sunscreen containing nicotinamide and panthenol affects photodamage, an international team of researchers gathered 14 Catalan participants and examined severely sun-damaged skin areas and less sun-damaged skin. We conducted imaging, molecular, and genetic experiments before and after 4 weeks of nicotinamide sunscreen use. The results show that severely sun-damaged skin is thicker and contains more cells called keratinocytes. Additionally, certain indicators of DNA damage and repair are more active in severely sun-damaged skin. Genetic analyses reveal that the photodamage process causes significant differences in certain genetic pathways such as cGMP-PKG and MAPK pathways. Using nicotinamide sunscreen leads to positive changes in several cellular processes, including the way cells divide, respond to stress, and produce collagen. In summary, this study gives us a deeper understanding of skin photodamage and underlines the potential benefits of adding nicotinamide to sunscreens, which could be a promising way to reduce the damage caused by UV radiation.

Extramammary Paget disease (EMPD) is an uncommon adenocarcinoma of apocrine gland-rich areas, presenting significant diagnostic challenges due to its nonspecific clinical appearance and frequent misidentification as benign, inflammatory skin conditions. Traditional diagnostic methods such as biopsy are invasive and uncomfortable, often required repeatedly due to high recurrence rates. Dermoscopy and non-invasive imaging techniques have been used but provide limited diagnostic accuracy due to their constraints in depth penetration and resolution. Recent advancements in imaging technologies, such as line-field confocal optical coherence tomography (LC-OCT), show promise in enhancing diagnostic precision while minimizing invasive procedures. LC-OCT merges high-resolution imaging with deep penetration capabilities, capturing detailed horizontal and vertical skin images akin to histopathology. This study evaluated the diagnostic performance of LC-OCT in detecting EMPD and its recurrence in 17 clinically suspicious anogenital regions, belonging to six patients. Data were collected prospectively at the patient’s bedside by an LC-OCT expert with poor training for EMPD, and, then, reviewed retrospectively by an independent LC-OCT expert with adequate training for EMPD and no concerns about time. The prospective examination yielded 64.7% accuracy (11 true results out of 17 total cases), 71.4% sensitivity (10 true positives out of 14 actual positives), and 33.3% specificity (1 true negative out of 3 actual negatives). The retrospective analysis achieved 94.1% accuracy (16 true results out of 17 total cases), 100% sensitivity (14 true positives out of 14 actual positives), and 66.7% specificity (2 true positives out of 3 actual positives), with the only false positive case being a difficult-to-diagnose concomitant presentation of a lichen sclerosus et atrophicus. Despite the need for specialized training, our results suggest that LC-OCT represents a valuable tool for accurately identifying EMPD and improving its management by reducing unnecessary biopsies. Further studies are needed to standardize its clinical application.