Benign Melanocytic Nevi Research Articles

Characterization of PRAME immunohistochemistry reveals lower expression in pediatric melanoma compared to adult melanoma.

Pediatric melanomas are rare tumors that have clinical and histological differences from adult melanomas. In adult melanoma, the immunohistochemical marker PRAME is increasingly employed as a diagnostic adjunct. PRAME is also under investigation as a target structure for next-generation immunotherapies including T-cell engagers. Little is known about the characteristics of PRAME expression in pediatric melanoma. In this retrospective study, samples from 25 pediatric melanomas were compared with control groups of melanomas in young adults (18-30 years; n = 32), adult melanoma (>30 years, n = 30), and benign melanocytic nevi in children (0-18 years; n = 30) with regard to the immunohistochemical expression of PRAME (diffuse PRAME expression >75%/absolute expression). Pediatric melanomas show lower diffuse PRAME expression (4%) and lower absolute PRAME expression (25%) compared to young adult melanomas (15.6%/46.8%) and adult melanomas (50%/70%). A significant age-dependent expression could be observed. An analysis of event-free survival shows no prognostic role for PRAME in pediatric melanoma and young adult melanoma, but a significant association with diffuse PRAME expression in adulthood. The age dependency of PRAME expression poses a potential pitfall in the diagnostic application of melanocytic tumors in young patients and may limit therapeutic options within this age group. The immunohistochemical expression of the tumor-associated antigen PRAME is an increasingly important diagnostic marker for melanocytic tumors and is gaining attention as a possible immunotherapeutic target in melanoma. As the available data primarily stem from adult melanoma, and given the clinical and histological distinctions in pediatric melanomas, our understanding of PRAME expression in this specific patient group remains limited. The age-dependent low PRAME expression shown here constrains the use of this marker in pediatric melanoma and may also limit the use of immunotherapeutic strategies against PRAME in young patients.

Role of dermoscopy in hyperpigmented skin disorders: A tertiary care centre experience

Dermoscopy, performed with a handheld instrument called dermatoscope, is a non-invasive and in-vivo technique for the evaluation of various skin lesions in clinical practice. Although many studies have shown the importance of dermoscopy in diagnosing skin lesions by supplementing naked-eye evaluation, Indian data on its usefulness is scarce. We aimed to describe dermoscopic findings in various pigmented conditions in skin of colour.A retrospective observational study was carried out in a tertiary care hospital in western India for the period of two years- October 2015 to September 2018. Patients were selected from the available records by using pre-specified selection criteria. Detailed demographic and clinical parameters were recorded. The dermoscopic examination was done using Dermlite DL3 polarised device. The histopathological findings, when available, were also evaluated. A total of 352 patients were identified, 181 males and 171 females. Out of the total number, 272 patients had melanocytic and 80 had non-melanocytic lesions. Benign melanocytic nevi (100 out of 272) and seborrheic keratosis (58 out of 70) were the most common observations for melanocytic and non-melanocytic lesions respectively. The study provides real-world data on a large scale for dermoscopic findings in hyperpigmented lesions in Indian patients. This study corroborates with observations from previous studies to suggest quick and non-invasive use of dermoscopy for reliable diagnosis. Larger studies in future may obviate the need for biopsy while managing these patients.

Evaluation of MMP-9, MMP-13, MMP-21, and TIMP-1 expressions in malign melanom, dysplastic nevi, and banal nevi.

Although the role of MMPs in the pathogenesis of melanoma is known, few studies have investigated their role in the development of nevi and dysplastic nevi. This study aims to search the expression differences of MMP-9, MMP-13, MMP-21, and TIMP-1 between malignant melanoma (MM), intradermal nevi (IDN), and dysplastic nevi (DN). MMP-9, MMP-13, MMP-21, and TIMP-1 antibodies were studied immunohistochemically for 60 cases in our pathology clinic archive between 2013 and 2014. The MM group had the highest expression percentage and intensity for MMP-9 (p<0.001). There was no statistical significance between MMP-13 expression intensities of lesion cells and stromal cells and stromal expression intensities (p>0.05). MMP-21 lesion staining intensities in DN and MM compared to IDN were statistically significant (p=0.001, p=0.011, respectively). For TIMP-1, there was a significant difference between the IDN and the MM group regarding the staining proportion of lesion cells (p<0.01). There was a statistically significant difference in all groups according to lesion cells' expression intensity. (IDN-DN p<0.001, IDN-MM p=0.044, DN-MM p<0.001). The following markers can be helpful when lesions cannot be differentiated; increased staining proportions and intensity of MMP-9 in both lesion and stromal cells favor MM in cases where MM and IDN cannot be differentiated. The increased MMP-13 staining proportion of lesion cells can favor DN in cases where the pathologist cannot differentiate DN and MM. Intense expression of MMP-21 by lesion cells can be a potential marker for evaluating the lesion in favor of DN in cases where DN and IDN cannot be differentiated. The high expression intensity of TIMP-1 in lesion cells can favor DN in cases where there is ambiguity between DN and MM. High expression proportion and intensity of stromal cells of TIMP-1 can be useable in favor of MM in cases where MM and DN cannot be differentiated.

MobileNet V2 Implementation in Skin Cancer Detection

Skin cancer is one of the most worrying diseases for humans. In Indonesia alone, skin cancer occupies the third position after cervical cancer and breast cancer. Currently, doctors still use the biopsy method to diagnose skin cancer. It is less effective because this method requires the performance of an experienced doctor, takes a long time, and is a painful process. Because of that, we need a way in which skin cancer can be classified using dermoscopic images to help doctors diagnose skin cancer earlier. Researchers proposed to classify skin cancer into seven classes, namely actinic keratoses, basal cell carcinoma, benign keratosis-like lesions, dermatofibroma, melanoma, melanocytic nevus, and vascular lesions. The method used in this study is a convolutional neural network (CNN) with the MobileNet V2 architecture. The dataset used is the HAM10000 dataset, with a total of 10015 images. In this study, a comparison was made between data augmentation, learning rate, epochs, and different amounts of data. Based on the test results, the highest accuracy results were obtained, namely 79%. The best model is implemented into a mobile application.

Understanding choroidal nevus risk factors for transformation into melanoma

A choroidal nevus is a common intraocular tumor in the United States, found in approximately 5% of Caucasian adults. The three main risks of melanocytic choroidal nevus include vision loss from a subfoveal nevus, development of subretinal fluid, and transformation of nevus into melanoma, a malignant counterpart. We explore clinical risk factors that predict benign melanocytic choroidal nevus transformation into a malignant choroidal melanoma. Based on a large analysis of 2,355 cases that were monitored longitudinally using multimodal imaging, the most recent list of clinical features includes tumor Thickness greater than 2 mm on ultrasonography, subretinal Fluid on optical coherence tomography, Symptomatic vision loss 20/50 or worse, Orange pigment on fundus autofluorescence, Melanoma hollow on ultrasonography, and DIaMeter greater than 5 mm on fundus photography. These factors are remembered with a mnemonic of the capital letters TFSOM-DIM for “To Find Small Ocular Melanoma Doing Imaging.” Analysis of these factors demonstrated a Kaplan-Meier mean five-year risk of 1% with no risk factors, 11% with any one factor, 22% with any two factors, 34% with any three factors, 51% with any four factors, and 55% with any five factors. There was no patient with six risk factors. Of those with combinations of four risk factors, six of 15 combinations yielded a 70%-100% rate of transformation; of those with combinations of five risk factors, two of five combinations yielded a 70%-100% rate of transformation. Choroidal nevus carries a risk for evolving into melanoma, and understanding of clinical and imaging features predictive of this outcome is highly important.

Standardized Computer-Assisted Analysis of PRAME Immunoreactivity in Dysplastic Nevi and Superficial Spreading Melanomas.

PRAME (PReferentially expressed Antigen in MElanoma) is a cancer testis antigen that is frequently expressed in melanoma compared to benign melanocytic proliferations and nevi. However, the interpretation of the intensity and distribution of PRAME immunostaining is not standardized a lot, which makes interpretation difficult. PRAME-stained histological slides of superficial spreading melanomas (SSM) and dysplastic nevi (DN) were digitized and analyzed using the digital pathology and image platform QuPath. t-tests and ROC AUCs were performed with SPSS. A p-value of <0.05 was used for statistical significance, and a ROC AUC score of >0.8 was considered a good result. A cut-off score was defined in an evaluation cohort and subsequently analyzed in an independent validation cohort. In total, 81 PRAME-stained specimens were included. The evaluation cohort included 32 (50%) SSM and 32 (50%) DN, and the mean of PRAME-positive cells/mm2 for the entire lesion was 455.3 (SD 428.2) in SSM and 60.5 (SD 130.1; p < 0.001) in DN. The ROC AUC of PRAME-positive cells of the entire lesion was 0.866, and in the epidermis it was 0.901. The defined cut-off score to distinguish between DN and SSM was 97.67 cells/mm2. In the validation cohort, 16 out of 17 cases (94.1%) were correctly classified by the cut-off score. The computer-aided assessment of PRAME immunostaining is a useful tool in dermatopathology to distinguish between DN and SSM. Lesions with a moderate expression and indifferent morphologic features will remain a challenge for dermatopathologists.

Dermoscopic features of an unusual case of targetoid hemosiderotic nevus

Targetoid hemosiderotic nevus (THN) is a rare variant of melanocytic nevus, characterized by a sudden development of a targetoid ecchymotic halo around a pre-existing nevus. THN clinically raises concern for malignant transformation due to its abrupt change in color and size. THN should be distinguished from other diseases showing a peripheral halo, including targetoid hemosiderotic hemangioma, halo nevus, and Meyerson nevus. Dermoscopy can help clinicians to differentiate THN from these diseases. The typical dermoscopic features of THN are known to be divided into two distinctive areas: the central melanocytic area and the peripheral ecchymotic area. In our case, dermoscopy revealed a novel bull’s eye pattern composed of a central area with characteristic features of benign melanocytic nevus, an intermediated white circular ring, and a peripheral milky red area. When a sudden change occurs in a pre-existing nodule showing targetoid features, dermoscopy should be considered before conducting a biopsy or surgical intervention.

36. Clinical utility of copy number alteration analysis in the evaluation of Melanocytic Lesions for diagnosis and prognosis

Melanocytic lesions range from benign to highly aggressive malignancies. Although the diagnosis is often straightforward histologically, ambiguous cases provide a dilemma with critical clinical implications. Copy number alteration (CNA) analysis, from formalin-fixed paraffin-embedded tissue, has emerged over the last two decades as a valuable tool for diagnosis of histologically challenging melanocytic lesions. Numerous studies, with various microarray platforms, demonstrate that the number of CNAs in malignant melanomas is higher than in benign melanocytic nevi with proposed cutoffs for adequate sensitivity and specificity. Targeted fluorescence in situ hybridization panels, utilizing probes to detect the CNAs most commonly seen in melanoma, are sufficient for diagnostic purposes. Furthermore, studies determined that CNAs have prognostic significance. Both the number of CNAs and detection of specific CNAs are helpful for risk stratification. To provide evidence-based recommendations for clinical utility of CNAs in melanocytic lesions, the Cancer Genomics Consortium Working Group for Melanocytic Lesions assessed 410 peer-reviewed articles selected from an extensive Ovid search of publications from 1998 through 2021. The group determined the power of CNAs for 1) aiding diagnosis, 2) stratifying risk, and 3) guiding clinical management. We present the evidence base for the clinical utility of CNA assessment in the workup of melanocytic lesions including ocular, mucosal, and cutaneous melanomas with characteristic findings in various subtypes. This working group has synthesized the findings to establish consensus recommendations for the interpretation of CNAs in melanocytic lesions and incorporation into standard clinical laboratory testing.

Colored Texture Analysis Fuzzy Entropy Methods with a Dermoscopic Application.

Texture analysis is a subject of intensive focus in research due to its significant role in the field of image processing. However, few studies focus on colored texture analysis and even fewer use information theory concepts. Entropy measures have been proven competent for gray scale images. However, to the best of our knowledge, there are no well-established entropy methods that deal with colored images yet. Therefore, we propose the recent colored bidimensional fuzzy entropy measure, , and introduce its new multi-channel approaches, and , for the analysis of colored images. We investigate their sensitivity to parameters and ability to identify images with different irregularity degrees, and therefore different textures. Moreover, we study their behavior with colored Brodatz images in different color spaces. After verifying the results with test images, we employ the three methods for analyzing dermoscopic images of malignant melanoma and benign melanocytic nevi. , , and illustrate a good differentiation ability between the two—similar in appearance—pigmented skin lesions. The results outperform those of a well-known texture analysis measure. Our work provides the first entropy measure studying colored images using both single and multi-channel approaches.

A Dermoscopic Inspired System for Localization and Malignancy Classification of Melanocytic Lesions

This study aims at developing a clinically oriented automated diagnostic tool for distinguishing malignant melanocytic lesions from benign melanocytic nevi in diverse image databases. Due to the presence of artifacts, smooth lesion boundaries, and subtlety in diagnostic features, the accuracy of such systems gets hampered. Thus, the proposed framework improves the accuracy of melanoma detection by combining the clinical aspects of dermoscopy. Two methods have been adopted for achieving the aforementioned objective. Firstly, artifact removal and lesion localization are performed. In the second step, various clinically significant features such as shape, color, texture, and pigment network are detected. Features are further reduced by checking their individual significance (i.e., hypothesis testing). These reduced feature vectors are then classified using SVM classifier. Features specific to the domain have been used for this design as opposed to features of the abstract images. The domain knowledge of an expert gets enhanced by this methodology. The proposed approach is implemented on a multi-source dataset (PH2 + ISBI 2016 and 2017) of 515 annotated images, thereby resulting in sensitivity, specificity and accuracy of 83.8%, 88.3%, and 86%, respectively. The experimental results are promising, and can be applied to detect asymmetry, pigment network, colors, and texture of the lesions.

Diagnostic utility of ERG immunostaining in dermatofibroma

AimsDermatofibroma/fibrous histiocytoma (DF/FH) is a common cutaneous mesenchymal neoplasm exhibiting benign biological behaviour. However, the immunohistochemical utility of erythroblast transformation-specific-related gene (ERG) for diagnosing DF remains unknown. The authors reviewed...

Real-time Intraoperative Dermoscopic Monitoring of Common Acquired Melanocytic Nevi Following Shave Excision.

The treatment of common acquired melanocytic nevus (CAMN) is mostly desired for cosmetic purposes due to which a number of "faster and less traumatizing" techniques have been developed. The major cause of recurrence is incomplete removal; there is a need for early detection of any residual pigment. This study aimed to assess the recurrence of common acquired melanocytic nevi and whether dermoscopy can be used as a noninvasive tool for the assessment of residual pigment following shave excision. A total of 100 patients of age more than 18 years with clinical features suggestive of common acquired melanocytic nevi were enrolled in the study. The nevi were assessed clinically and dermoscopically and, if found benign, were excised using shave excision. The specimen obtained was sent for histopathological examination. Dermoscopy was used immediately after shave excision for observing any residual pigment and, if present, was removed using radiofrequency current. The patients were followed up at 6 and 12 weeks for recurrence. On histopathology, 87% nevi were intradermal, 8% were compound, and 5% had insufficient tissue for diagnosis, which were clinically diagnosed as junctional nevi. Dermoscopy immediately after shave excision helped in detecting residual pigment in 91% nevi, which was immediately ablated with radiofrequency, thus decreasing the risk of recurrences. Recurrences were seen in 33% nevi and all were intradermal with the presence of hair in the majority (66.67%) of them. Shave excision is a minimally invasive and easily performed procedure. Dermsocopy can be used for assessing residual pigment after shave excision and thus reducing the risk of recurrences. On combining shave excision with radiofrequency ablation and assessing by dermoscopy, majority of patients were satisfied with the cosmetic results. Using dermoscope for follow-up helps in early recognition of recurrence and thus appropriate treatment can be provided at the earliest.

The Safety and Effectiveness of Elastic Scattering Spectroscopy and Machine Learning in the Evaluation of Skin Lesions for Cancer

Background Elastic scattering spectroscopy (ESS) is an optical biopsy technique that can distinguish between a normal and abnormal tissue in vivo without the need to remove it. The handheld device measures ESS spectra of skin lesions and classifies lesions as either malignant or benign with an output of “Investigate Further” or “Monitor,” respectively, with positive results accompanied by a spectral score output from 1 to 10, indicating how similar the lesion is to the malignant lesions the device was trained on. The algorithm was trained and validated with over 11,000 spectral scans from over 3500 skin lesions. Objective The purpose of this study was to evaluate the safety and effectiveness of the handheld ESS device in detecting the most common types of skin cancer. Methods A prospective, single-arm, investigator-blinded, multicenter study conducted at 4 investigational sites in the United States was performed. Patients who presented with skin lesions suggestive of melanoma, basal cell carcinoma, squamous cell carcinoma, and other highly atypical lesions were evaluated with the handheld ESS device. A validation performance analysis was performed with 553 lesions from 350 subjects with algorithm version 2.0. An independent test set of 281 lesions was selected and used to evaluate device performance in the detection of melanoma, basal cell carcinoma (BCC), and squamous cell carcinoma (SCC). Statistical analyses included overall effectiveness analyses for sensitivity and specificity as well as subgroup analyses for lesion diagnoses. Results The overall sensitivity of the device was 92.3% (95% CI: 87.1 to 95.5%). The sensitivity for subgroups of lesions was 95% (95% CI 75.1% to 99.9%) for melanomas, 94.4% (95% CI 86.3% to 98.4%) for BCCs, and 92.5% (95% CI 83.4% to 97.5%) for SCCs. The overall device specificity was 36.6% (95% CI 29.3% to 44.6%). There was no statistically significant difference between the dermatologist performance and the ESS device (P=.2520). The specificity of the device was highest for benign melanocytic nevi (62.5%) and seborrheic keratoses (78.2%). The overall positive predictive value (PPV) was 59.8%, and the negative predictive value (NPV) was 81.9% with the study’s malignancy prevalence rate of 51%. For a prevalence rate of 5%, the PPV was estimated to be 7.1%, and the NPV was estimated to be 98.9%. For a prevalence rate of 7%, the PPV was estimated to be 9.8%, and the NPV was estimated to be 98.4%. For a prevalence rate of 15%, the PPV was estimated to be 20.3%, and the NPV was 96.4%. Conclusions The handheld ESS device has a high sensitivity for the detection of melanoma, BCC, and SCC. Coupled with clinical exam findings, this device can aid physicians in detecting a variety of skin malignancies. The device output can aid teledermatology evaluations by helping frontline providers determine which lesions to share for teledermatologist evaluation as well as potentially benefitting teledermatologists’ virtual evaluation, especially in instances of suboptimal photo quality. Acknowledgments This study was sponsored by Dermasensor Inc. Conflicts of Interest None declared.

Expression and Significance of AQP3 in Cutaneous Lesions.

Aquaporin 3 (AQP3) is the membrane channel of water and involved in fluid homeostasis. The aim of this study was to reveal the expression and significance of AQP3 in cutaneous lesions. We analyzed AQP3 mRNA levels using RT-PCR in 311 cutaneous lesions and confirmed AQP3 expression in these lesions by immunohistochemistry. AQP3 mRNA was detected in normal epidermis, seborrheic keratosis, solar keratosis, Bowen's disease, squamous cell carcinoma, eccrine poroma, apocrine carcinoma, and sebaceoma; however, AQP3 mRNA was absent in basal cell carcinoma, nevocellular nevus, or malignant melanoma. By immunohistochemistry, diffuse AQP3 expression was seen in all keratotic lesions including seborrheic keratosis, verruca vulgaris, molluscum contagiosum, solar keratosis, Bowen's disease, and squamous cell carcinoma. Diffuse AQP3 expression was also present in all extramammary Paget's disease. No AQP3 staining was obtained in basal cell carcinoma. Positive AQP3 staining was seen in sweat gland tumors including hidradenoma, eccrine poroma, and apocrine carcinoma. Among sebaceous tumors, AQP3 expressed diffusely in all sebaceous hyperplasia and sebaceous adenoma, but not in sebaceous carcinomas. Only focal AQP3 staining was seen in nevocellular nevus and no AQP3 staining in melanoma. Our findings indicate the function of AQP3 maintained in most skin tumors. AQP3 may be used for differential diagnosis in skin tumors.

A Case Series Outlining the Relationship between Dolichoectasia and Ectrodactyly-Ectodermal Dysplasia-Clefting Syndrome

Ectrodactyly-Ectodermal Dysplasia-Clefting Syndrome (EEC) is a rare heritable condition marked by ectodermal dysplasia with nails, teeth, sweat glands, and hair, eye and lacrimal duct malformations, midfacial hypoplasia, ectrodactyly (loss of fingers or toes), syndactyly, clinodactyly, auricular anomalies, short height, orofacial cleft palates, genitourinary anomalies, malformations within the central nervous system (CNS) leading to mental impairment or hearing loss, nevocellular nevi, flat noses, and hypopigmentation (National Foundation for Ectodermal Dysplasias 2021 and Cyriac & Lashpa 1980).

Transcriptome Analysis Reveals the Molecular Immunological Characteristics of Lesions in Patients with Halo Nevi When Compared to Stable Vitiligo, Normal Nevocytic Nevi and Cutaneous Melanoma

BackgroundGiven their similar appearance and histology, halo nevi (HN) were considered as a type of vitiligo. However, whether HN have stronger immune response than stable vitiligo (VL) remains unclear. In addition, the molecular alterations in HN compared with normal nevocytic nevi (NN) and primary cutaneous melanoma (MM) must be determined. This study aimed to systematically characterize the molecular immunological features of HN.MethodsSkin samples from patients with HN, VL, NN, and MM were obtained with informed consent. Each of the four groups underwent transcriptome sequencing and data analysis were for pairwise comparison. Quantitative real-time PCR (RT-qPCR) was conducted to confirm the transcriptional expression of some differentially expressed genes (DEGs) that were closely related to immunity.ResultsA total of 441 and 1507 DEGs were found in the HN/NN and HN/MM groups, respectively. Compared with those of VL, HN lesions contained 162 up-regulated DEGs and 12 down-regulated DEGs. Bioinformatics analysis showed that the up-regulated genes in HN were substantially enriched in immune response, immune deficiency, and immune rejection; biological stimulation (virus, bacteria); and proliferation and activation of immune cells. Immune cell composition analysis also confirmed high expression levels of multiple immunocytes in HN.ConclusionThe molecular immune mechanisms of HN and VL were similar, but the immune activity of HN was stronger than that of VL. Innate and adaptive immunity were involved in the pathogenesis and progression of HN and VL.

A Case Series Outlining the Relationship between Dolichoectasia and Ectrodactyly-Ectodermal Dysplasia-Clefting Syndrome

Ectrodactyly-Ectodermal Dysplasia-Clefting Syndrome (EEC) is a rare heritable condition marked by ectodermal dysplasia with nails, teeth, sweat glands, and hair, eye and lacrimal duct malformations, midfacial hypoplasia, ectrodactyly (loss of fingers or toes), syndactyly, clinodactyly, auricular anomalies, short height, orofacial cleft palates, genitourinary anomalies, malformations within the central nervous system (CNS) leading to mental impairment or hearing loss, nevocellular nevi, flat noses, and hypopigmentation

Germ Line Mutations in the Thyroid Hormone Receptor Alpha Gene Predispose to Cutaneous Tags and Melanocytic Nevi.

Background: Many physiological effects of thyroid hormone (TH) are mediated by its canonical action via nuclear receptors (TH receptor α and β [TRα and TRβ]) to regulate transcription of target genes. Heterozygous dominant negative mutations in human TRα mediate resistance to thyroid hormone alpha (RTHα), characterized by features of hypothyroidism (e.g., skeletal dysplasia, neurodevelopmental retardation, constipation) in specific tissues, but near-normal circulating TH concentrations. Hitherto, 41 RTHα cases have been recorded worldwide.Methods: RTHα cases (n = 10) attending a single center underwent cutaneous assessment, recording skin lesions. Lesions excised from different RTHα patients were analyzed histologically and profiled for cellular markers of proliferation and oncogenic potential. Proliferative characteristics of dermal fibroblasts and inducible pluripotent stem cell (iPSC)-derived keratinocytes from patients and control subjects were analyzed.Results: Multiple skin tags and nevi were recorded in all cases, mainly in the head and neck area with a predilection for flexures. The affected patients had highly deleterious mutations (p.E403X, p.E403K, p.F397fs406X, p.A382PfsX7) involving TRα1 alone or mild/moderate loss-of-function mutations (p.A263V, p.L274P) common to TRα1 and TRα2 isoforms. In four patients, although lesions excised for cosmetic reasons were benign intradermal melanocytic nevi histologically, they significantly overexpressed markers of cell proliferation (K17, cyclin D1) and type 3 deiodinase. In addition, oncogenic markers typical of basal cell carcinoma (Gli-1, Gli-2, Ptch-1, n = 2 cases) and melanoma (c-kit, MAGE, CDK4, n = 1) were markedly upregulated in skin lesions. Cell cycle progression and proliferation of TRα mutation-containing dermal fibroblasts and iPSC-derived keratinocytes from patients were markedly increased.Conclusions: Our observations highlight frequent occurrence of skin tags and benign melanocytic nevi in RTHα, with cutaneous cells from patients being in a hyperproliferative state. Such excess of skin lesions, including nevi expressing oncogenic markers, indicates that dermatologic surveillance of RTHα patients, monitoring lesions for features that are suspicious for neoplastic change, is warranted.

Langerhans Cells as Morphologic Mimickers of Atypical Melanocytes on Reflectance Confocal Microscopy: A Case Report and Review of the Literature.

Pagetoid spread of melanocytes in the epidermis is a common indicator of melanocytic atypia, both histopathologically and with reflectance confocal microscopy (RCM). Specifically on RCM, large, bright, atypical dendritic and/or roundish cells are characteristic of melanoma. However, intraepidermal Langerhans cells (ILC) create the potential for diagnostic ambiguity on RCM. We describe one case of a pigmented facial lesion that was initially diagnosed as lentigo maligna (LM) due to numerous atypical perifollicular dendritic cells on RCM. Additionally, we present the findings of a literature review for similar reported cases conducted by searching the following terms on PubMed: reflectance confocal microscopy, RCM, lentigo maligna, melanoma, Langerhans cells, dendritic cells, and atypical cells. In our case, the lesion was determined to be a solar lentigo on histopathology. Immunohistochemistry (IHC) with CD1a identified the atypical-appearing cells as ILC, as it did in 54 reported cases of benign lesions (benign melanocytic nevus, Sutton/halo nevus, labial melanotic macule, and solar lentigo) misdiagnosed as malignant on RCM (melanoma, lip melanoma, lentigo maligna, and LM melanoma). According to our case and the literature, both ILC and atypical melanocytes can present with atypical-appearing dendritic and/or roundish cells under RCM. Currently, there is no method to distinguish the two without IHC. Therefore, the presence of pagetoid cells should continue to alert the confocalist of a potential neoplastic process, prompting biopsy, histopathologic diagnosis, and IHC differentiation.

Application of generated mask method based on Mask R-CNN in classification and detection of melanoma

ObjectiveMelanoma is a type of malignant skin cancer with high mortality, and its incidence is increasing rapidly in recent years. At present, the best treatment is surgical resection after early diagnosis. However, due to the high visual similarity between melanoma and benign melanocytic nevus, coupled with the scarcity and imbalance of data, traditional methods are difficult to achieve good recognition and detection results. Similarly, many machine learning methods have been applied to the task of skin disease detection and classification. However, the accuracy and sensitivity of the experiments are still not satisfactory. Therefore, this paper proposed a method to identify melanoma more efficiently and accurately. MethodWe implemented a Mixed Skin Lesion Picture Generate method based on Mask R-CNN (MSLP-MR) to solve the problem of data imbalance. Besides, we designed a melanoma detection framework of Mask-DenseNet+ based on MSLP-MR. This method used Mask R-CNN to introduce the method of mask segmentation, and combined with the idea of ensemble learning to integrate multiple classifiers for weighted prediction. Compared with the ablation experiments, the accuracy, sensitivity and AUC of the proposed network classification are improved by 2.56%, 29.33% and 0.0345. ResultThe experimental results on the ISIC dataset shown that the accuracy of the algorithm is 90.61%, the sensitivity reaches 78.00%, which is higher than the original methods; the specificity reaches 93.43%; and the AUC reaches 0.9502. ConclusionThe method is feasible and effective, and achieves the preliminary goal of melanoma detection. It is greatly improved the detection accuracy and reached the level of visual diagnosis of doctors.