Sun-damaged Skin Research Articles

Nanofat in Plastic Reconstructive, Regenerative, and Aesthetic Surgery: A Review of Advancements in Face-Focused Applications.

Nanofat is a relatively novel technique in fat grafting that has gained significant interest in the fields of regenerative medicine, aesthetic and translational research. It involves the extraction of autologous fat from a patient, which is then transformed into "nanofat", consisting of small fat particles with a diameter of less than 0.1 mm and containing high concentrations of stem cells and growth factors. This article focuses on the use of nanofat in facial rejuvenation and its potential for lipomodelling. Fat tissue is a "stem cell depot" and nanofat contains many stem cells that can differentiate into various cell types. The Lipogem technology, developed in 2013, enables the isolation of nanofat with an intact perivascular structure, utilizing the high concentration of mesenchymal stromal cells near the pericytes of the adipose vascular system. Nowadays nanofat is used primarily for cosmetic purposes particularly in rejuvenating and improving the appearance of the skin, especially the face. Indeed, it has wide applicability; it can be used to treat fine lines, wrinkles, acne scars, sun-damaged skin, scar repair, and as an alopecia treatment. However, further studies are needed to assess the long-term efficacy and safety of this technique. In conclusion, nanofat is a safe and minimally invasive option for tissue regeneration with considerable therapeutic potential. This study reviews the application and effects of nanofat in regenerative medicine and facial cosmetic surgery.

DP18 Extraocular sebaceous carcinoma in situ

Abstract Extraocular sebaceous carcinoma in situ (SCIS) is exceedingly rare with < 10 cases reported in the literature (Jeong KM, Seo JY, Kim A et al. Extraocular sebaceous carcinoma in situ concurrent with actinic keratosis: a case report and review of the literature. Korean J Dermatol 2021; 59:307–9). An 80-year-old man reported a 3-month history of a right forehead lesion that had been bleeding. This was a subtle 5 × 5 mm papule on clinical examination, and dermoscopy showed arborizing telangiectasia. Past medical history was significant for 20 basal cell carcinomas, one squamous cell carcinoma, Bowen disease and actinic keratoses. Histology showed sun-damaged skin with a partially eroded neoplasm of lobular architecture, with surface and infundibular epithelium containing atypical sebocytes and squamous cells with no infiltrative growth pattern, which was consistent with SCIS and was fully excised. Immunohistochemistry revealed patchy adipophilin and androgen receptor staining and stronger epithelial membrane antigen staining. Furthermore, there was preserved expression of MSH2, MSH6, MLH1 and PMS2. Sebaceous carcinoma in situ is a debated entity not formally recognized in the classification of sebaceous neoplasms. Kazakov et al. reported five cases of dermal sebaceous tumours with ‘benign’ architectural features (well-circumscribed and no evidence of invasion) but with cytological atypia (abnormal mitoses and pleomorphism) (Kazakov D, Kutzner H, Spagnolo DV et al. What is extraocular cutaneous sebaceous carcinoma in situ? Am J Dermatopathol 2010; 32:857–8). The authors questioned whether these cases represented sebaceous adenomas with atypia or sebaceous carcinomas (Kazakov et al.). In response, it has been argued that such architectural–cytological discordant tumours can be regarded as SCIS owing to the fact that, by definition, carcinoma in situ is a cancer that remains wholly at the site of origin. However, it is argued that these lesions have an unclear origin and may not arise from sebaceous glands in the skin, unlike the more common aggressive periorbital sebaceous carcinomas that arise from meibomian glands and glands of Zeis (Kazakov et al.). It has been postulated that a SCIS diagnosis should be reserved for intraepidermal tumours not extending beyond the epidermal basement membrane, which is a vanishing minority of sebaceous neoplasms (Kazakov et al.). Similar to our case, a 2021 case report identified SCIS without any connection to an adnexal component but concurrent with actinic keratosis. These authors proposed that the tumour cells of intraepidermal squamous neoplasia can differentiate towards malignant sebocytes (Jeong et al.). Although controversial, SCIS appears to have reasonable, clear histological criteria for diagnosis and an excellent prognosis, with no reports of recurrence following surgical excision. We feel it is important to increase identification to avoid the overtreatment of such lesions.

P57 Retrospective review of patients with lentigo maligna treated with topical 5% imiquimod (Aldara®) at a single tertiary UK centre: need for more practical standardized treatment guidelines in the UK

Abstract Lentigo maligna (LM) is an in situ melanoma arising on chronically sun-damaged skin predominantly on the head and neck. While surgery is the gold standard treatment for LM, imiquimod 5%, which is an immune-response modifier, is a well-reported off-licence treatment in both primary and adjuvant settings. Various treatment regimens have been published. We present our retrospective experience of using imiquimod to treat LM over 10 years at a UK tertiary melanoma centre. We report on indications, treatment regimes, side-effects and treatment efficacy. We identified 71 patients with LM treated with imiquimod with a mean age at diagnosis of 73.3 years. Ninety-three per cent were located on the head and neck. Forty-three per cent (n = 29/67) of patients were treated primarily (following punch biopsy diagnosis or incomplete excision with visible pigmentation remaining) and 57% (n = 38/67) with adjuvant treatment (excision with narrow or close margins, < 3 mm with no visible pigmentation). Invasive disease was seen in 17% of those treated primarily and 45% treated with adjuvant therapy. There were various treatment regimens, but the majority (55%) had treatment prescribed five times weekly for 11–12 weeks, with no significant difference in treatment regimens between the two treatment groups. Inflammation was recorded as none (20%), mild (21%), moderate (21%) and severe (20%). Side-effects were redness (40%), pain (17%), ulceration (7%) and systemic symptoms (6%). Fifty-nine per cent of the primary group had visible clearance; a previous study reported a 71% clinical response in this cohort. Three of the responders relapsed, with two progressing to LM melanoma within 8 years. Forty-eight per cent remained disease free, with a mean follow-up of 27 months. Of those treated with adjuvant therapy, 89% remained clinically disease free at mean follow-up of 19 months. Recurrence in the adjuvant group was reported as 5.6% (Lallas A, Moscarella E, Kittler H et al. Real-world experience of off-label use of imiquimod 5% as an adjuvant therapy after surgery or as a monotherapy for lentigo maligna. Br J Dermatol 2021; 185:675–7). Our limitations include a lack of post treatment biopsies. In 2021, an Australian study reported a practical guide on the use of imiquimod for LM (Guitera P, Waddell A, Paton E et al. A practical guide on the use of imiquimod cream to treat lentigo maligna. Australas J Dermatol 2021; 62:478–85). We propose the need for clearer UK guidelines describing the escalation and de-escalation of treatment in the event of no response and toxicity, respectively. We suggest using a patient application diary to ensure compliance and document changes in treatment and inflammation.

Clinical, Dermoscopic, and Histological Characteristics of Melanoma Patients According to the Age Groups: A Retrospective Observational Study.

Although the role of melanoma risk factors is well documented, their correlation with patients' age is less frequently analyzed. The analysis was performed among 189 melanoma patients in different age groups, including <30 years, 31-60 years, and >60 years, to investigate the risk factors, topography, and coexistence of morphological features of 209 melanomas (dermoscopic and histopathological). Among the youngest age group, no correlation with the presence of estimated risk factors was found. The most common dermoscopic pattern was spitzoid and multicomponent asymmetric. The group of middle-aged patients was the most diverse in terms of the occurrence of risk factors, solar lentiginosis, dermoscopic patterns, topography, histological subtypes, and invasiveness of melanomas. The oldest group characterized a strong correlation between solar lentiginosis, NMSC comorbidity, the prevalence of facial melanomas, the dermoscopic pattern of melanoma arising on chronic sun-damaged skin, and regression. The findings regarding the presence of age-specific features in melanoma patients, especially in the youngest and middle-aged groups, might be helpful for clinicians and to target secondary prevention efforts.

Identification of Novel Dermoscopic Patterns for "Featureless Melanoma": Clinical-Pathological Correlation.

Diagnosis of melanoma can be very difficult because of its phenotypic and histological heterogeneity. Difficult-to-diagnose melanoma can be represented by mucosal melanoma, pink lesions, amelanotic melanoma (amelanotic lentigo maligna, amelanotic acral melanoma, desmoplastic melanoma), melanoma arising on sun-damaged facial skin, and "featureless melanoma". The aim of the study was to improve the identification of featureless melanoma (scoring 0-2 according to the 7-point-checklist) describing the variegated dermoscopic features and their histopathological correlation. Study samples included all melanomas excised based on clinical and/or dermoscopic findings in the period between January 2017 and April 2021. Before excisional biopsy, all lesions were recorded by means of digital dermoscopy at the department of Dermatology. Only lesions with a diagnosis of melanoma and a high quality of dermoscopic images were included in this study. After clinical and dermoscopic evaluation of 7-point checklist score, single dermoscopic and histological features were considered for lesions with a score of 2 or lower and a diagnosis of melanoma (corresponding to dermoscopic featureless melanoma). A total of 691 melanomas fulfilled inclusion criteria and were retrieved from the database. The 7-point checklist evaluation identified 19 "negative-featureless" melanoma. The 100% of the lesions with score 1 showed a globular pattern. Dermoscopy is still the best diagnostic method for melanoma. The 7-point checklist provides a simplification of standard pattern analysis because of the algorithm based on a scoring system and the lower number of features to recognize. In the daily practice it is more comfortable for many clinicians to keep in mind a list of principles that may help in the decision.

Junctional Nevus and Early Melanoma on Sun-Damaged Skin of the Head/Neck: a Clinico-Pathologic Challenge.

Melanoma on the head/neck area can show subtle clinical, dermoscopic and histologic features at early stages, being difficult to differentiate from junctional nevi. This case series aims to raise awareness on the topic of misdiagnosis of early lentigo maligna as junctional nevi. From the databases of three pigmented lesion clinics in Italy, Australia, and France, we retrieved all cases of lesions of the head/neck area with an initial histopathologic diagnosis of junctional nevus (JN) or dysplastic junctional nevus (DJN) which subsequently recurred and were ultimately diagnosed as melanoma. Moreover, we also retrieved those cases with an initial diagnosis of JN/DJN made on a partial biopsy that were diagnosed as melanoma after complete surgical removal. Here we report 14 cases in which the initial histologic diagnosis was junctional nevus or dysplastic junctional nevus. The lesions recurred over time with a final diagnosis of lentigo maligna. Clinicians should critically question a given histologic diagnosis of junctional or dysplastic junctional nevus on the head/neck area if the clinical or dermoscopic features are discordant. Clinico-pathologic correlation is the best way to increase diagnostic accuracy and optimize management for the patient.

The anatomical distribution of lentiginous melanoma (lentigo maligna and lentigo maligna melanoma): Differences according to sex.

The anatomical distribution of lentiginous melanoma (lentigo maligna and lentigo maligna melanoma): Differences according to sex.

007 Commensal papillomaviruses role in sun-damaged skin homeostasis

007 Commensal papillomaviruses role in sun-damaged skin homeostasis

Transcriptomic Study on Human Skin Samples: Identification of Two Subclasses of Actinic Keratoses.

Actinic keratoses (AKs) are sun-damaged skin areas that affect 20% of the European adult population and more than 50% of people aged 70 years and over. There are currently no clinical or histological features allowing us to identify to which clinical class (i.e., regression or progression) an AK belongs. A transcriptomic approach seems to be a robust tool for AK characterization, but there is a need for additional studies, including more patients and elucidating the molecular signature of an AK. In this context, the present study, including the largest number of patients to date, is the first aiming at identifying biological features to objectively distinguish different AK signatures. We highlight two distinct molecular profiles: AKs featuring a molecular profile similar to squamous cell carcinomas (SCCs), which are called "lesional AKs" (AK_Ls), and AKs featuring a molecular profile similar to normal skin tissue, which are called "non-lesional AKs" (AK_NLs). The molecular profiles of both AK subclasses were studied, and 316 differentially expressed genes (DEGs) were identified between the two classes. The 103 upregulated genes in AK_L were related to the inflammatory response. Interestingly, downregulated genes were associated with keratinization. Finally, based on a connectivity map approach, our data highlight that the VEGF pathway could be a promising therapeutic target for high-risk lesions.

Genomic Profiling of Lentigo Maligna within an Interim Registry Analysis​

Background: Pigmented lesion analysis remains a challenging aspect of dermatology. The DermTech Melanoma Test (‘the test’) is a non-invasive genomic test designed to rule-out melanoma. It consists of the pigmented lesion assay, which detects RNA products of Long Intergenic Non-Coding RNA 00518 (LINC00518) and Preferentially Expressed Antigen in Melanoma (PRAME), and an add-on assay for DNA promoter mutations in telomerase reverse transcriptase (TERT). In previous studies, the test was found to have a negative predictive value ≥99%. This interim analysis of a registry study examines the genomic patterns of the Lentigo Maligna (LM) subtype of melanoma. Methods: Between April 2021 and March 2022, multiple geographically diverse sites throughout the US submitted data to a registry to assess real-world use of the test. Approximately 8,000 clinically atypical lesions were tested. After receiving the test result, providers followed their clinical judgement for biopsy decision. Histopathologic diagnoses for biopsied lesions were correlated with test results and all melanomas were sorted into LM subtype vs non-LM subtype. In addition, lesions that were noted to be on sun exposed skin and/or noted to have solar elastosis and called atypical melanocytic hyperplasia were included. Results: At the 1-year mark of the registry, there were roughly 8000 unique entries. Of those, 1003 expressed one or more genomic markers from the DMT and had records available, and 134 (13.2%) were found to be melanoma or melanoma in-situ. More than a third (n=46, 34.3%) of the melanomas were of the Lentigo Maligna sub-type, with 7 of those being Lentigo Maligna Melanoma (LMM). Seven additional lesions were called atypical junctional melanocytic hyperplasia (AJMH) on sun-damaged skin. This group of 53 LM, LMM, and AJMH lesions were all evaluated for correlations to the DMT markers. LINC was the most commonly expressed genomic marker (n=45, 84.9%), with PRAME (n=36, 67.9%) and TERT (n=24, 45.3%) following. Most invasive tumors (LMM) expressed all three markers (n=4) and all 7 expressed LINC. Conclusion: While the original validation study included the LM subtype, this interim registry analysis demonstrates real-world use of the DMT in assessing pigmented macules concerning for LM. Over 1/3 of the melanomas reported in the registry were LM subtypes. LINC had a higher correlation with the lentigo maligna subtype of melanoma and was present in all invasive tumors. While AJMH is considered borderline, it may be worthwhile in the clinical context to group AJMH lesions with LM due to similarities in treatment.

Pyruvate and lactate based hydrogel film inhibits UV radiation-induced skin inflammation and oxidative stress

Solar skin damage is one of the most common diseases among outdoor workers. An important cause for the damage is the ultraviolet and infrared rays in sunlight, which are absorbed by the skin in large amounts, leading to severe skin inflammation and oxidative stress. Therefore, physical prevention by shielding the light from harmful wavelengths can be an effective method of skin protection from radiation. However, for existing skin lesions, prompt treatment is essential to avoid the aggravation of the injury and promote repair. Therefore, to improve the therapeutic effect on sun-damaged skin, we attempted to design a system with a dual purpose of eliminating toxic free radicals and modulating tissue inflammatory response. Here, we designed and synthesized a poly-acryloyl lysine (P-Ac-Lys) and polyvinyl alcohol-dihydroxyphenylalanine (PVA-DOPA) composite hydrogel (PAL@PVA-DOPA Hydrogel) loaded with lactate and pyruvate, that exhibites a good free radical scavenging activity and an excellent ability to modulate the inflammatory response. Experimental results showe that this hydrogel film could effectively reduce the UV-induced skin inflammation response, alleviate pathological damage and promote the recovery of the damaged skin.

Characterizing Dermal Transcriptional Change in the Progression from Sun-Protected Skin to Actinic Keratosis

Understanding early tumorigenic events have obvious diagnostic and prognostic implications, particularly in the skin since this is the site of more US cancer diagnoses than any other organ (Rogers et al., 2015). Actinic keratosis (AK) are dysplastic keratinocyte lesions characterized by irregularly shaped scaly papules frequently manifesting on sun-damaged skin, and are considered precursor lesions which can develop into cutaneous squamous cell carcinoma (cSCC), the second most common keratinocyte cancer (Siegel et al., 2017).

Advances in Photodynamic Therapy for the Treatment of Actinic Keratosis and Nonmelanoma Skin Cancer: A Narrative Review.

Photodynamic therapy (PDT) with photosensitization using 5-aminolevulinic acid (ALA) [including a nanoemulsion (BF-200 ALA)] is approved in the USA for the treatment of actinic keratoses (AKs); another derivative, methyl aminolevulinate, is not approved in the USA but is used in Europe. For AK treatment, the photosensitizer may be applied to individual AK lesions or, depending on treatment regimen, to broader areas of sun-damaged skin to manage field cancerization, although not all products are approved for field treatment. ALA-PDT and photosensitizers have also been used off-label for the treatment of nonmelanoma skin cancers, primarily basal cell carcinomas (BCCs) and cutaneous squamous cell carcinomas (cSCC). Advantages of PDT include potentially improved cosmesis and patient satisfaction; disadvantages include pain and duration of treatment. Alternative illumination approaches, including intense pulsed light as well as pulsed-dye lasers, have also been used successfully. Pretreating the affected tissue or warming during incubation can help to increase photosensitizer absorption and improve therapeutic efficacy. Combinations of multiple treatments are also under exploration. Reducing incubation time between photosensitizer application and illumination may significantly reduce pain scores without affecting treatment efficacy. Substituting daylight PDT for a conventional illumination source can also reduce pain without compromising efficacy. The objective of this narrative review is to describe current and ongoing research in the use of topical photosensitizers and modified light delivery regimens to achieve improved therapeutic outcomes with less toxicity in patients with AK, cSCC, BCC, and field cancerization.

Changes in the cell walls on fruit skin of Beurré D´Anjou pears (Pyrus communis L.) associated with sunburn injury

• Sunburn reduced cuticular microcrack area and skin thickness, and increased cell wall thickness. • Neutral sugars (NS) content increased in two pectin fractions (WSP and CSP) in sunburn skin. • Hemicellulose and lignin contents increased in sunburn skin. • The expression of Exp and XTH genes increased in response to sunburn. The purpose of this work was to evaluate the effects of sunburn on pear fruit skin at the structural, biochemical, and molecular levels. Pears ( Pyrus communis L.) cv. Beurré D'Anjou were collected at the official commercial harvest time and classified into three groups based on levels of sublethal sunburn: no sunburn (S0), mild sunburn (S1), and moderate sunburn (S2). Skin anatomy was characterized by SEM imaging, cell wall components were quantified by spectrophotometric techniques, and the expression of different genes related to cell wall remodeling was measured in S0, S1, and S2 tissues. Sun-damaged skin cells had reduced size and thickened walls. In the cuticular surface, a reduction of microcracking area, correlated with the intensity of the damage, was further noted. Cell wall fractionation revealed changes in the distribution of neutral sugars (NS) following sunburn, although no differences in uronic acid (UA) content were observed in the different pectin fractions. Hemicellulose and lignin contents were significantly ( P <0.05) increased in sun-damaged tissues. Expression levels of genes encoding polygalacturonase (PcPG2), β-galactosidase (PcGAL2 and PcGAL4), xyloglucan endotransglycosylase (PcXET), and expansin (PCExp1) were increased in the skin of sun-damaged (S1 and S2) fruit. These results indicate that sunburn alters the anatomy and cell wall structure and composition of pear fruit skin, and stimulates different mechanisms involved in the acquisition of stress tolerance.

Determining the Association Between Melanomas and Fields of Melanocytic Dysplasia.

Some have proposed that melanomas in situ may be associated with fields of melanocytic dysplasia, particularly on sun-damaged skin, whereas others maintain that the atypical junctional melanocytic hyperplasia (MH) at the periphery of melanomas is simply background junctional MH of sun-damaged skin. The biological potential of atypical junctional MH at the periphery of melanomas is uncertain. We examined whether atypical junctional MH was intrinsic to the melanoma itself (ie, melanoma-associated field of melanocytic dysplasia) or was simply the predictable junctional MH associated with long-standing sun exposure. We retrospectively compared 106 cutaneous melanoma excisions without residual tumor with 105 nonmelanoma cutaneous tumor excisions (ie, basal cell or squamous cell carcinomas) without residual tumor. MH with atypia occurred significantly more frequently in melanoma than in nonmelanoma cutaneous tumor excisions (55.7% vs. 24.8%, P < 0.001). Solar elastosis occurred significantly less frequently in melanoma than in nonmelanoma cutaneous tumor excisions; 33.0% of melanoma excisions and 8.6% of nonmelanoma excision samples exhibited no solar elastosis, respectively (P < 0.001). After controlling for solar elastosis using multivariable linear regression, the association between MH with atypia and melanoma excisions remained significant (P < 0.001). Our results, therefore, demonstrate that melanomas were associated with atypical junctional MH that could not solely be accounted for by the extent of sun damage as measured by solar elastosis.

Incidence and Risk Factors for Incidental Cancer on Melanoma Wide Excisions

IntroductionCancer patients and survivors have a high risk of developing additional malignancies. Patients who undergo melanoma excision often have sun-damaged skin and are predisposed to concurrent and subsequent skin cancers. The unexpected finding of an incidental cancer on melanoma wide excisions can require further surgery and delays adjuvant treatment. We aimed to determine the incidence and risk factors for incidental skin cancers in patients who had surgical excision of melanoma. MethodsOur single-center retrospective study analyzed all patients diagnosed with primary melanoma at our institution from July 1, 2019 through June 30, 2020. We included patients with localized cutaneous melanoma who underwent surgical excision and had relevant pathology data available. Descriptive statistics and univariate analyses were performed on the demographic, clinical, and pathological data collected. We analyzed differences between the groups with and without incidental cancer to ascertain risk factors using chi-squared tests and Wilcoxon rank sum tests. Dunn's tests with Bonferroni correction were performed for multiple pairwise comparisons. ResultsThere were 642 patients who met the criteria for inclusion, of whom 13 (2.0%) had incidental cancers identified on a pathologic assessment. Six (46%) had incidental squamous cell carcinoma and seven (54%) had basal cell carcinoma. With regard to management of incidental cancer, three (23%) patients required additional surgery for margin re-excision. Risk factors for incidental cancers in melanoma excision included older age (median 79 versus 62 y, P < 0.001), male sex (P = 0.042), and primary tumor location in the head/neck region relative to trunk (P < 0.01) or extremity (P < 0.01) primary sites. ConclusionsAlthough the frequency of incidental findings on melanoma excision is low, certain patients are at a greater risk including older male individuals with head/neck melanomas. These findings can be used to improve preoperative counseling of at-risk patients when melanoma excision is planned.

Immunohistochemical expression of p53, Ki67, α-SMA, CD44 and CD31 in different histological subtypes of basal cell carcinoma.

Basal cell carcinoma (BCC) is a common, locally invasive tumor that arises within sun-damaged skin and rarely develops on the palms and soles or mucous membranes. Men generally have higher rates of BCC than women. Incidence also increases with age and the median age of diagnosis is 68 years old. Mortality from BCC is rare and cases of aggressive, local destructive, metastatic BCCs are more likely from tumors with aggressive histopathological (HP) patterns. The aim of this study was to investigate and correlate the immunohistochemical expression of p53, Ki67, alpha-smooth muscle actin (α-SMA), cluster of differentiation (CD)44 and CD31 with both aggressive and nonaggressive types of BCCs. In our study, we observed a varied staining pattern for p53, with the highest reactivity noticed in the peripheral palisading zone. The staining pattern for Ki67 was similar to p53, with a more pronounced reaction in the periphery of the tumor. We found different Ki67 and p53 expression among the various subtypes of BCC. The CD31 reactivity, mostly seen in the stroma, was positive in all BCCs and varied significantly between its different HP subtypes. Regarding stromal expression of α-SMA, the adenoid and basosquamous types had the most intense reaction in our study. The CD44 tumor expression was correlated in our study to the aggressive pattern of BCCs.

Clinical Characteristics of Actinic Keratosis Associated with the Risk of Progression to Invasive Squamous Cell Carcinoma: A Systematic Review.

Background: Actinic keratosis (AK) is one of the most common lesions on chronically sun-damaged skin that has the risk of progression to invasive squamous cell carcinoma (SCC). With the possibilities of using digital technologies for following-up skin lesions and their increased use in the past few decades, our objective was to update the review by Quaedvlieg et al., 2006, and to review prospective studies from 2005 onwards to identify the clinical characteristics of AK that later progressed to SCC. Methods: The PubMed, Scopus, and ScienceDirect databases were searched for relevant articles. The search had the following criteria: English language, human subjects and year from 2005 onwards. The study protocol was registered in the Prospero database with the record number CRD42020200429 and followed the PRISMA guidelines. The risk-of-bias assessment was performed using the QUIPS tool. Results: From the 5361 studies screened, 105 reports were evaluated for eligibility, and 2 articles with 621 patients were included. The main AK types associated with the development of SCC were found to be baseline AK, also known as a long-standing AK, and merging AK, also called an “AK patch”.

The detectability of intraepidermal melanocytes-A narrative review of immunohistochemical studies.

Some intraepidermal lesions, even the nonmelanocytic ones, may mimic melanoma in situ. The cytoplasmic clarity in atypical basal cells, architectural disorder with cell aggregates or nest-like structures within the epidermis often cause challenge particularly in sun-damaged skin. The aim of this review is to evaluate the effectiveness of the most often used immunohistochemical melanocyte markers in the diagnosis of intraepidermal lesions. All the analyzed markers can be useful in detection of intraepidermal melanocytes that occur more densely in lentigo maligna than in solar lentigo or sun-damaged skin. However, the number of these cells is underestimated by HMB-45 and Mel-5. The cytoplasmic Melan-A staining may overestimate melanocyte number and highlight the dendritic process. Atypical melanized keratinocytes in actinic keratoses and nest-like structures in lichenoid dermatoses may mimic atypical melanocytes in melanomas in situ. S-100 remains a marker of high sensitivity but low specificity. The nuclear localization of MITF, SOX-10, and PRAME overcomes the problem of melanosome transfer to cells of other types. Neither MITF nor SOX-10 is detectable in keratinocytes, which makes them useful in distinguishing actinic keratoses from melanomas in situ. The use of markers considered as melanocyte specific suggests that lichenoid dermatoses constitute a heterogeneous group of lesions.

A convolutional neural network based system for detection of actinic keratosis in clinical images of cutaneous field cancerization

Areas of cutaneous field cancerization (CFC) occur in sun-damaged skin and are prone to skin cancer development. Actinic keratosis (AK) is the pathognomonic lesion of CFC. Therefore, the reliable and non-invasive AK burden assessment is essential to assist clinicians in delivering patient-tailored therapeutic interventions and support the objective evaluation of emerging therapeutic modalities. Herein, we introduce a system for automated AK detection in CFC areas.For the differentiation of AK from healthy skin areas and co-localized benign growths (Seborrheic Keratosis/Lentigo Solaris; SK/LS), cross-polarized digital photographs of afflicted skin surfaces were taken, and a convolutional neural network (AKCNN) whose convolution part was optimally transferred from a pre-trained VGG16 was implemented. For the detection of multifocal AK in wide skin regions, superpixels were employed to generate region patches for the subsequent evaluation. AKCNN was implemented and evaluated in 19739, 43067, and 12,205 image patches of AK, SK/LS, and healthy skin, respectively, originating from 46 patients. AKCNN performance was assessed in two ways: (a) patch classification using the macro averaged F1 score and (b) AK burden evaluation in broad skin areas using an adapted region-based F1 (aF1) score.Using raw clinical images, AKCNN exhibited a macro F1 of 0.78 at patch level and a region-based aF1 of 0.81, with good tolerance against image scaling.The proposed system efficiently uses cross-polarized clinical photography to assess the AK burden within the CFC.