Line-field confocal optical coherence tomography in dermato-oncology: A literature review towards harmonized histopathology-integrated terminology.

Non-invasive diagnostics like line-field confocal optical coherence tomography (LC-OCT) are being implemented in dermato-oncology. However, unification of terminology in LC-OCT is lacking. By reviewing the LC-OCT literature in the field of dermato-oncology, this study aimed to develop a unified terminological glossary integrated with traditional histopathology. A PRISMA-guided literature-search was conducted for English-language publications on LC-OCT of actinic keratosis (AK), keratinocyte carcinoma (KC), and malignant melanoma (MM). Study characteristics and terminology were compiled. To harmonize LC-OCT terminology and integrate with histopathology, synonymous terms for image features of AK, KC, and MM were merged by two authors, organized by skin layer and lesion-type. A subset of key LC-OCT image-markers with histopathological correlates that in combination were typical of AK, squamous cell carcinoma in situ (SCCis), invasive squamous cell carcinoma (SCC), basal cell carcinoma (BCC), and MM in traditional histopathology, were selected from the glossary by an experienced dermatopathologist. Seventeen observational studies of AK (7 studies), KC (13 studies), MM (7 studies) utilizing LC-OCT were included, with 117 terms describing either AK, KC, or MM. These were merged to produce 45 merged-terms (61.5% reduction); 5 assigned to the stratum corneum (SC), 23 to the viable epidermis, 2 to dermo-epidermal junction (DEJ) and 15 to the dermis. For each lesion, mandatory key image-markers were a well-defined DEJ and presence of mild/moderate but not severe epidermal dysplasia for AK, severe epidermal dysplasia and well-defined DEJ for SCCis, interrupted DEJ and/or dermal broad infiltrative strands for invasive SCC, dermal lobules connected and/or unconnected to the epidermis for BCC, as well as single atypical melanocytes and/or nest of atypical melanocytes in the epidermis or dermis for MM. This review compiles evidence on LC-OCT in dermato-oncology, providing a harmonized histopathology-integrated terminology and key image-markers for each lesion. Further evaluation is required to determine the clinical value of these findings.

Immunoexpression of Ki67, P16 and Beta-catenin in precursor lesions of cutaneous squamous cell carcinoma.

Cutaneous squamous cell carcinoma (CSCC) is the second most common type of skin cancer, after basal cell carcinoma, representing about 10-20% of all malignant skin tumors. The mortality rates of CSCC approach those of renal and oropharyngeal carcinomas, as well as melanoma, with the increasing of the risk once metastases and perineural invasion occur. Both actinic keratosis (AK) and Bowen's disease (BD) are direct precursors with the potential for progression to CSCC. In this study, we analyzed the expression of Ki67, P16 and Beta-catenin in the precursor lesions of CSCC in relation to histological prognostic parameters, respectively between them, with the aim of identifying possible correlations with a role in prognosis. Ki67 and P16 presented higher scores in advanced precancerous lesions, such as keratinocyte intraepithelial neoplasia (KIN) III and BD and low scores in seborrheic keratosis (SK). The immunoreactivity to the investigated markers confirms the multistage skin carcinogenesis, and their involvement starting from the initiation phase of the cancer process. The importance of the studied markers in the evolution and prognosis of precancerous lesions of CSCC is also supported by the linear correlations revealed between the immunoexpressions of P16, Ki67 and the membranous immunoexpression of Beta-catenin in AK.

Characterization of the skin microbiome in normal and cutaneous squamous cell carcinoma affected cats and dogs.

Human cutaneous squamous cell carcinomas (SCCs) and actinic keratoses (AK) display microbial dysbiosis with an enrichment of staphylococcal species, which have been implicated in AK and SCC progression. SCCs are common in both felines and canines and are often diagnosed at late stages leading to high disease morbidity and mortality rates. Although recent studies support the involvement of the skin microbiome in AK and SCC progression in humans, there is no knowledge of this in companion animals. Here, we provide microbiome data for SCC in cats and dogs using culture-independent molecular profiling and show a significant decrease in microbial alpha diversity on SCC lesions compared to normal skin (P ≤ 0.05). Similar to human skin cancer, SCC samples had an elevated abundance of staphylococci relative to normal skin-50% (6/12) had >50% staphylococci, as did 16% (4/25) of perilesional samples. Analysis of Staphylococcus at the species level revealed an enrichment of the pathogenic species Staphylococcus felis in cat SCC samples, a higher prevalence of Staphylococcus pseudintermedius in dogs, and a higher abundance of Staphylococcus aureus compared to normal skin in both companion animals. Additionally, a comparison of previously published human SCC and perilesional samples against the present pet samples revealed that Staphylococcus was the most prevalent genera across human and companion animals for both sample types. Similarities between the microbial profile of human and cat/dog SCC lesions should facilitate future skin cancer research. IMPORTANCE: The progression of precancerous actinic keratosis lesions (AK) to cutaneous squamous cell carcinoma (SCC) is poorly understood in humans and companion animals, despite causing a significant burden of disease. Recent studies have revealed that the microbiota may play a significant role in disease progression. Staphylococcus aureus has been found in high abundance on AK and SCC lesions, where it secretes DNA-damaging toxins, which could potentiate tumorigenesis. Currently, a suitable animal model to investigate this relationship is lacking. Thus, we examined the microbiome of cutaneous SCC in pets, revealing similarities to humans, with increased staphylococci and reduced commensals on SCC lesions and peri-lesional skin compared to normal skin. Two genera that were in abundance in SCC samples have also been found in human oral SCC lesions. These findings suggest the potential suitability of pets as a model for studying microbiome-related skin cancer progression.

Bowen disease is not synonymous with intraepidermal squamous cell carcinoma.

The terms 'Bowen disease' and 'intraepidermal squamous cell carcinoma' are sometimes considered synonymous. In this paper we present historical, clinical, histological and molecular evidence that this is incorrect. The term Bowen disease should be reserved for a subset of intraepidermal squamous cell carcinoma with a distinctive and reproducible morphological pattern, described in detail by Bowen in 1912. One other common subset of intraepidermal squamous cell carcinoma represents progression of actinic keratosis. In some cases the separation of these two common patterns of intraepidermal squamous cell carcinoma can be challenging and there are patterns of intraepidermal squamous cell carcinoma which appear to represent other distinct pathways. However, there is emerging biological evidence to support this distinction and reason to suspect that the types of invasive squamous cell carcinoma which arise from these different pathways may show important clinical and biological differences, particularly in the era of targeted and immunomodulatory therapy for advanced disease.

Expression Analysis of Retinal G Protein-coupled Receptor and its Correlation with Regulation of the Balance between Proliferation and Aberrant Differentiation in Cutaneous Squamous Cell Carcinoma.

Retinal G protein-coupled receptor (RGR), a photosensitive protein, functions as a retinal photoisomerase under light conditions in humans. Cutaneous squamous cell carcinoma (cSCC) is linked to chronic ultraviolet exposure, which suggests that the photoreceptor RGR may be associated with tumorigenesis and progression of squamous cell carcinoma (SCC). However, the expression and function of RGR remain uncharacterized in SCC. This study analysed RGR expression in normal skin and in lesions of actinic keratosis, Bowen's disease and invasive SCC of the skin with respect to SCC initiation and development. A total of 237 samples (normal skin (n = 28), actinic keratosis (n = 42), Bowen's (n = 35) and invasive SCC (n = 132) lesions) were examined using immunohistochemistry. Invasive SCC samples had higher expression of RGR protein than the other samples. A high immunohistochemical score for RGR was associated with increased tumour size, tumour depth, Clark level, factor classification, and degree of differentiation and a more aggressive histological subtype. In addition, RGR expression was inversely correlated with involucrin expression and positively correlated with proliferating cell nuclear antigen (PCNA) and Ki67 expression. Furthermore, RGR regulates SCC cell differentiation through the PI3K-Akt signalling pathway, as determined using molecular biology approaches in vitro, suggesting that high expression of RGR is associated with aberrant proliferation and differentiation in SCC.

The cutaneous microbiome in skin cancer - A systematic review.

The overall incidence of skin cancer has risen over the past half a decade worldwide and is associated with significant morbidity and mortality. Recent advances in molecular testing have allowed us to better characterize microbiome alterations in skin cancer. However, literature specific to skin microbiome and skin cancer remain heterogenous and scattered. A systematic review was performed to identify the existing literature and its usefulness in providing microbiome-based biomarkers. A search of the databases (PubMed, Medline, EMBASE, GoogleScholar) was conducted from June to July 2022 in accordance with the PRISMA guidelines. A total of 1,543 articles were identified, of which 16 were selected for inclusion in the review (11 articles on cancer of the keratinocytes and 5 articles on melanoma). Increased Staphylococcus (S.) aureus prevalence with decline in commensal organisms is seen in squamous cell carcinoma (SCC) and actinic keratosis (AK), compared to healthy skin. While the microbiome of melanoma appears to be distinct from healthy skin, limited data is available to draw meaningful conclusions. Our review summarizes the current evidence on the microbiome of keratinocyte skin cancers and melanoma. The study establishes that the microbiome of these cancers is altered from healthy skin and that this dysbiosis involves both pathogenic and commensal organisms.

Role of asprosin and meteorin-like peptide in progression of actinic keratosis to squamous cell carcinoma.

Squamous cell carcinoma (SCC) often develops from an underlying premalignant lesion. Factors that affect the progression of actinic keratosis (AK) to invasive SCC are not fully known. Asprosin (ASP) and meteorin-like peptide (METRNL) are adipokines that are involved primarily in glucose metabolism. We investigated the expression of ASP and METRNL in AK and SCC to evaluate the role of these adipokines in the development of SCC. We used 15 SCC specimens, 12 AK specimens and 12 healthy control skin specimens. ASP and METRNL protein expression in tumor and surrounding tissue was evaluated using immunohistochemistry. ASP expression in tumor tissue was significantly greater in the SCC group than in the control and AK groups, but it did not differ significantly between the AK and control groups. A positive correlation was observed for both ASP and METRNL expressions between tumor tissue and adjacent epidermis, hair follicles, sebaceous gland, eccrine gland, inflammatory cells and vascular structures. ASP and METRNL may exert pro-tumor effects toward development of invasive SCC. The expression intensity of ASP and METRNL can be used as a biomarker of risk of progression to SCC.

Dermoscopy of Lentiginous Melanomas and Equivocal Benign Pigmented Macules of the Scalp: A Case-Control Multicentric Study.

INTRODUCTION: Although the dermoscopic features of facial lentiginous melanomas (LM), including lentigo maligna and lentigo maligna melanoma, have been extensively studied, the literature about those located on the scalp is scarce. This study aims to describe the dermoscopic features of scalp LM and assess the diagnostic accuracy of dermoscopy to discriminate them from equivocal benign pigmented macules. METHODS: Consecutive cases of scalp LM and histopathology-proven benign but clinically equivocal pigmented macules (actinic keratoses, solar lentigos, seborrhoeic keratoses, and lichen planus-like keratoses) from four referral centres were included. Dermoscopic features were analysed by two blinded experts. The diagnostic performance of a predictive model was assessed. RESULTS: 56 LM and 44 controls were included. Multiple features previously described for facial and extrafacial LM were frequently identified in both groups. Expert's sensitivity to diagnose scalp LM was 76.8% (63.6-87.0) and 78.6% (65.6-88.4), with specificity of 54.5% (38.9-69.6) and 56.8% (41.0-71.7), and fair agreement (kappa coefficient 0.248). The strongest independent predictors of malignancy were (OR, 95% CI) chaos of colour (15.43, 1.48-160.3), pigmented reticular lines (14.96, 1.68-132.9), increased density of vascular network (3.45, 1.09-10.92), and perifollicular grey circles (2.89, 0.96-8.67). The predictive model achieved 85.7% (73.8-93.6) sensitivity, 61.4% (45.5-75.6) specificity, and 81.5 (73.0-90.0) area under curve to discriminate benign and malignant lesions. A diagnostic flowchart was proposed, which should improve the diagnostic performance of dermoscopy. CONCLUSION: Both facial and extrafacial dermoscopic patterns can be identified in scalp LM, with considerable overlap with benign pigmented macules, leading to low specificity and interobserver agreement on dermoscopy.

Efficacy and safety of tirbanibulin 1% ointment in actinic keratoses: Data from two phase-III trials and the real-life clinical practice presented at the European Academy of Dermatology and Venereology Congress 2022.

BACKGROUND: The 31st European Academy of Dermatology and Venereology (EADV) Congress took place between 7th and 10th of September 2022 in Milan, Italy. OBJECTIVES: We report presented clinical data on the efficacy/effectiveness, safety and tolerability of tirbanibulin 1% ointment that has recently been licensed for actinic keratosis (AK) of the face or scalp in adults. METHODS: Summary of presentations given at the EADV Congress. RESULTS: Prof. Pellacani presented two post hoc analyses from two phase-III trials with AK patients (NCT03285477 [N = 351] and NCT03285490 [N = 351]): A descriptive analysis of medical history, concomitant medications, and safety results confirming a favourable profile for tirbanibulin showing that number of baseline AK lesions was not correlated to severity of local skin reactions. The latter analysis showed that cases of tirbanibulin application site pain or pruritus were few, and most were found to be mild. Prof. Kunstfeld reported six real-life clinical cases in Austria showing good tirbanibulin effectiveness, safety and tolerability for the treatment of new or recurring AK lesions. Results demonstrated that after 2- to 4-month follow-up, tirbanibulin was well tolerated and effective in AK patients. Presentations by Dr. Patel confirmed good outcomes and tolerability of tirbanibulin in Olsen grade 1-2 AK (N = 12) and porokeratosis patients (N = 4) treated once daily for 5 consecutive days in the United Kingdom. Furthermore, real-world experience in solid organ transplant recipients (N = 2) demonstrated effectiveness of tirbanibulin in skin field cancerization treatment. A symposium sponsored by Almirall was conducted during the congress in which Dr. Hadshiew and Dr. Lear brought together their clinical experience in Germany and the United Kingdom respectively. Interesting clinical cases of 5 consecutive days of tirbanibulin treatment compared to other treatments were discussed with attendees, as well as current treatment needs of AK patients. CONCLUSIONS: This article provides an overview of presentations and symposium discussions, summarizing key phase-III results and real-life clinical experience with tirbanibulin shared by dermatologists across Europe.

Full-face ALA-PDT for facial actinic keratosis: Two case reports.

We reported two cases of full-face 5-aminolevulinic acid-photodynamic therapy (ALA-PDT) for facial multiple actinic keratosis (AK). After the full-face ALA-PDT, we observed that the AK lesions on the faces of the patients were completely cleared and facial rejuvenation was achieved. In our follow-up, one patient was free of recurrence for over 13 months and the other one for over 28 months. The experience of these two cases may indicate that full-face ALA-PDT has an excellent therapeutic effect while potentially preventing the recurrence of AK.

Dermoscopic Evaluation of Actinic Changes in the Lips of Indigenous Children Living at High Altitude in Ecuador: A Descriptive Study.

BACKGROUND High altitude increases sunlight exposure, resulting in actinic keratosis, which predisposes people to skin cancer. The dermoscopy procedure evaluates keratotic and pigmented skin changes. This study aimed to describe the clinical and dermoscopic actinic changes in the lips of 25 indigenous children living at high altitude in Ecuador. MATERIAL AND METHODS An observational study was conducted in a public school in the Andes region of Ecuador (August-November 2019). Twenty-five children, males and females, age 5-15 years were assessed by complete physical examination, digital dermoscopic photographs, and punch biopsies. Descriptive statistics and Fisher's exact test were used to summarize and analyze the data. RESULTS We included 17 (68%) boys and 8 (32%) girls with a mean age of 9.8±2.0 years. Clinical lips findings reported desquamation [52% Upper Lip (UL); 40% Lower Lip (LL)], fissuring (8% UL; 8% LL), scabs (8% UL; 8% LL), and discoloration (40% UL; 20% LL). Dermoscopic features included a white-yellow lip color (24% UL; p=0.02). The main morphologic pattern of blood vessels was monomorphic (88% UL; p<0.001), polymorphous (60% LL; p<0.001), dotted pattern (64% UL; 28% LL; p=0.02), and linear-irregular (32% UL; 72% LL; p=0.01). Girls had radiating white structures on UL (p=0.025), while boys presented white structureless areas (UL 63.6%; LL 77.8%; p=0.032). No differences in dermoscopic findings were observed according to Fitzpatrick scale score (FSS). Punch biopsies showed no indications of actinic cheilitis. CONCLUSIONS Dermoscopic features in indigenous children living in high altitudes were related to actinic damage, but histopathological findings were negative.

Single-cell sequencing highlights heterogeneity and malignant progression in actinic keratosis and cutaneous squamous cell carcinoma.

Cutaneous squamous cell carcinoma (cSCC) is the second most frequent of the keratinocyte-derived malignancies with actinic keratosis (AK) as a precancerous lesion. To comprehensively delineate the underlying mechanisms for the whole progression from normal skin to AK to invasive cSCC, we performed single-cell RNA sequencing (scRNA-seq) to acquire the transcriptomes of 138,982 cells from 13 samples of six patients including AK, squamous cell carcinoma in situ (SCCIS), cSCC, and their matched normal tissues, covering comprehensive clinical courses of cSCC. We identified diverse cell types, including important subtypes with different gene expression profiles and functions in major keratinocytes. In SCCIS, we discovered the malignant subtypes of basal cells with differential proliferative and migration potential. Differentially expressed genes (DEGs) analysis screened out multiple key driver genes including transcription factors along AK to cSCC progression. Immunohistochemistry (IHC)/immunofluorescence (IF) experiments and single-cell ATAC sequencing (scATAC-seq) data verified the expression changes of these genes. The functional experiments confirmed the important roles of these genes in regulating cell proliferation, apoptosis, migration, and invasion in cSCC tumor. Furthermore, we comprehensively described the tumor microenvironment (TME) landscape and potential keratinocyte-TME crosstalk in cSCC providing theoretical basis for immunotherapy. Together, our findings provide a valuable resource for deciphering the progression from AK to cSCC and identifying potential targets for anticancer treatment of cSCC.

Inflammation of actinic keratosis from chemotherapy in a relapsed multiple myeloma patient.

A man in his 60 s with a history of actinic keratosis (AK) and relapsed IgG kappa multiple myeloma (MM) recently received VD-PACE (bortezomib, dexamethasone, cisplatin, doxorubicin, cyclophosphamide, etoposide) chemotherapy and presented with numerous haemorrhagic, scaly lesions on his scalp and face. He also had sepsis from methicillin-sensitive Staphylococcus aureus (MSSA) bacteraemia. Since the lesions were only present in the areas of pre-existing AK, a diagnosis of inflammation of AK secondary to chemotherapy was made. Sepsis was treated with appropriate antibiotics, and inflammation of AK was managed with topical steroids, leading to complete recovery.

Skin Cancers in Medicare Beneficiaries With Actinic Keratoses.

Importance: Actinic keratoses (AK) are common premalignant skin lesions with a small risk of progressing to cutaneous squamous cell carcinoma (SCC). There is some evidence that patients with AKs also have increased risks of other skin cancers beyond SCC. However, the absolute risks of skin cancer in patients with AKs are unknown. Objective: To calculate the absolute and relative risks of future skin cancer in Medicare beneficiaries with AKs. Design, Setting, and Participants: This retrospective cohort study was performed using a deidentified, random sample of 4 999 999 fee-for-service Medicare beneficiaries from 2009 through 2018. Patients with treated AKs were included, and patients with seborrheic keratoses (SKs) were included as a comparator group. All patients were required to have at least 1 year between data set entry and first AK or SK. Patients with a history of skin cancer were excluded. Data were analyzed from September 2022 to March 2023. Main Outcomes and Measures: Outcomes were first surgically treated skin cancer, including keratinocyte carcinoma (including SCC and basal cell carcinoma [BCC]) and melanoma. The absolute risks of skin cancer in patients with AKs were evaluated. Skin cancer risks in patients with AKs were compared with patients with SKs using adjusted competing risks regression. Results: A total of 555 945 patients with AKs (mean [SD] age, 74.0 [7.4] years; 55.4% female) and 481 024 patients with SKs (mean [SD] age, 73.3 [7.3] years; 72.4% female) were included. The absolute risk of skin cancer after a first AK was 6.3% (95% CI, 6.3%-6.4%) at 1 year, 18.4% (95% CI, 18.3%-18.5%) at 3 years, and 28.5% (95% CI, 28.4%-28.7%) at 5 years. Patients with AKs had increased risk of skin cancer compared with patients with SKs (any skin cancer: adjusted hazard ratio [aHR], 2.17; 95% CI, 2.15-2.19; keratinocyte carcinoma: aHR, 2.20; 95% CI, 2.18-2.22; SCC: aHR, 2.63; 95% CI, 2.59-2.66; BCC: aHR, 1.85; 95% CI, 1.82-1.87; and melanoma: aHR, 1.67; 95% CI, 1.60-1.73). Conclusions and Relevance: In this cohort study, older patients with AKs had substantial absolute risks, as well as elevated relative risks, of skin cancer. AKs may be clinical markers of UV exposure and increased skin cancer risk, including SCC, BCC, and melanoma. However, guidelines are lacking for follow-up skin cancer surveillance in patients with AKs. Efforts to develop evidence-based recommendations for skin cancer surveillance in patients with AKs are paramount.

Modified painless photodynamic therapy for facial multiple actinic keratosis in China: A prospective split-face control study.

BACKGROUND: Aminolevulinic acid photodynamic therapy (ALA-PDT) is an effective treatment for multiple actinic keratosis (AK). However, PDT-induced pain often discontinues the therapy to reduce its efficacy, limiting its application. If modified painless PDT schedule with shorter photosensitizer dressing and higher dose illumination could achieve good efficacy in AK, it is still unknown. OBJECTIVES: To explore the efficacy and pain tolerance of the modified painless PDT (M-PDT) in facial multiple AK. METHODS: A split-face controlled clinical study including 14 patients with facial multiple AK was conducted. The patients received conventional PDT (C-PDT) on the left and M-PDT in the contralateral area. The left area (C-PDT) was illuminated by a red light-emitting diode light (144 J/cm2 ) after applying the 10% ALA cream for 3 h; the other had illumination for a total light dose of 288 J/cm2 after applying the 10% ALA cream for 0.5 h. The primary endpoint was the lesion clearance rate at 1-month postthree sessions of PDT. Secondary endpoints included pain scores, the incidence of adverse events during treatment, and cosmetic outcomes. RESULTS: At 1 month following three treatments, the total lesion clearance rate was comparable between M-PDT and C-PDT (91.6% vs. 89.0%). While the lesion clearance rate of M-PDT was higher than that of C-PDT in the Grade III lesions (86.5% vs. 72.0%, respectively) (p < 0.05). M-PDT achieved a 100% lesion clearance rate for Grade I lesions earlier than C-PDT, with M-PDT treated twice and C-PDT treated thrice. Moreover, the pain score during illumination was significantly lower for M-PDT than for C-PDT (p < 0.01). Regarding photoaging, the Global Subjective Skin Aging Assessment score showed that the total and atrophy scores of C-PDT and M-PDT were significantly improved, and M-PDT also reduced discoloration. There was no significant difference in adverse reactions between C-PDT and M-PDT. CONCLUSIONS: M-PDT is comparable to C-PDT's efficacy for treating facial multiple AK, resulting in much lower pain scores.

Oral Nicotinamide for Actinic Keratosis Prevention in Kidney Transplant Recipients: A Pilot Double-Blind, Randomized, Placebo-Controlled Trial.

BACKGROUND: Oral nicotinamide (NAM) has shown promise in preventing actinic keratoses (AKs) in trials based outside of the United States. We assessed the efficacy of oral NAM supplementation in kidney transplant recipients with a history of keratinocyte carcinoma. MATERIAL AND METHODS: Patients enrolled in a 2-week run-in phase, during which NAM 1000 mg was taken twice daily. After a washout period, patients who tolerated the run-in phase were randomized to NAM 500 mg twice daily or placebo. At baseline, 4, 8, and 12 months, dermatologists conducted full-body skin exams to document area-specific AKs. Routine lab work was collected to ensure the stability of renal allograft function. RESULTS: The dosage was reduced from 1000 to 500 mg due to gastrointestinal symptoms in the run-in phase. Patients were randomized to NAM (n = 10) or placebo (n = 11). At 12 months, mean AK count was 30.8 (95% CI -11.7-73.4) for NAM and 26.6 (95% CI 10.8-42.5) for placebo. The difference in percent AK count change at 12 months compared with baseline was 259.8% (95% CI -385.9 to 905.5) for NAM and 72.4% (95% CI -118.6 to 263.5) for placebo. The between-group difference in percent AK change was not significant (P = .38). There was no attrition in the placebo group and 40% attrition in the NAM arm. DISCUSSION: Nicotinamide did not decrease AK development among kidney transplant recipients. Limitations include drug tolerability, small sample size, and single-center trial nature.

Artificial intelligence-based PRO score assessment in actinic keratoses from LC-OCT imaging using Convolutional Neural Networks.

BACKGROUND AND OBJECTIVES: The histological PRO score (I-III) helps to assess the malignant potential of actinic keratoses (AK) by grading the dermal-epidermal junction (DEJ) undulation. Line-field confocal optical coherence tomography (LC-OCT) provides non-invasive real-time PRO score quantification. From LC-OCT imaging data, training of an artificial intelligence (AI), using Convolutional Neural Networks (CNNs) for automated PRO score quantification of AK in vivo may be achieved. PATIENTS AND METHODS: CNNs were trained to segment LC-OCT images of healthy skin and AK. PRO score models were developed in accordance with the histopathological gold standard and trained on a subset of 237 LC-OCT AK images and tested on 76 images, comparing AI-computed PRO score to the imaging experts' visual consensus. RESULTS: Significant agreement was found in 57/76 (75%) cases. AI-automated grading correlated best with the visual score for PRO II (84.8%) vs. PRO III (69.2%) vs. PRO I (66.6%). Misinterpretation occurred in 25% of the cases mostly due to shadowing of the DEJ and disruptive features such as hair follicles. CONCLUSIONS: The findings suggest that CNNs are helpful for automated PRO score quantification in LC-OCT images. This may provide the clinician with a feasible tool for PRO score assessment in the follow-up of AK.

Non-invasive diagnosis of early cutaneous squamous cell carcinoma.

Early cutaneous squamous cell carcinoma (cSCC) can be challenging to diagnose using clinical criteria as it could present similar to actinic keratosis (AK) or Bowen's disease (BD), precursors of cSCC. Currently, histopathological assessment of an invasive biopsy is the gold standard for diagnosis. A non-invasive diagnostic approach would reduce patient and health system burden. Therefore, this study used non-invasive sampling by tape-stripping coupled with data-independent acquisition mass spectrometry (DIA-MS) proteomics to profile the proteome of histopathologically diagnosed AK, BD and cSCC, as well as matched normal samples. Proteomic data were analysed to identify proteins and biological functions that are significantly different between lesions. Additionally, a support vector machine (SVM) machine learning algorithm was used to assess the usefulness of proteomic data for the early diagnosis of cSCC. A total of 696 proteins were identified across the samples studied. A machine learning model constructed using the proteomic data classified premalignant (AK + BD) and malignant (cSCC) lesions at 77.5% accuracy. Differential abundance analysis identified 144 and 21 protein groups that were significantly changed in the cSCC, and BD samples compared to the normal skin, respectively (adj. p < 0.05). Changes in pivotal carcinogenic pathways such as LXR/RXR activation, production of reactive oxygen species, and Hippo signalling were observed that may explain the progression of cSCC from premalignant lesions. In summary, this study demonstrates that DIA-MS analysis of tape-stripped samples can identify non-invasive protein biomarkers with the potential to be developed into a complementary diagnostic tool for early cSCC.

Eccrine Ductal Carcinoma of the Eyelid.

The authors present the third example of an eccrine ductal carcinoma of the eyelid. A woman in her early 70s presented with a lesion of the central right lower eyelid margin in the vicinity where an actinic keratosis was diagnosed by biopsy 2.75 years previously. Her dermatologist and ophthalmologist monitored the area of actinic keratosis, and it was stable for 2.5 years until the area became ulcerated and thickened with the loss of eyelashes. A wedge resection disclosed a squamous cell carcinoma in situ and a separate eccrine ductal carcinoma. The eccrine ductal carcinoma had in situ tumor thickening, an eccrine duct component, and an invasive tumor infiltrating the tarsal plate and replacing the normal meibomian glands. The invasive eccrine ductal carcinoma only mildly thickened the tarsal plate and was most likely an incidental finding in a biopsy prompted by the squamous cell carcinoma in situ. The 5-year relative survival rate for malignant apocrine-eccrine tumors is approximately 97%, and our patient is alive and without evidence of local or distant tumor recurrence 5.5 years following the excision of her eyelid tumor.