Melanocytic Nevi Research Articles

A rare case of spotted grouped pigmented naevus: Congenital follicular melanocytic naevus.

A rare case of spotted grouped pigmented naevus: Congenital follicular melanocytic naevus.

More than one shade of pink as a marker of early amelanotic/hypomelanotic melanoma.

Amelanotic/hypomelanotic melanoma (AHM) may be difficult to diagnose because of a lack of pigmentation. To evaluate whether dermoscopy can be useful for the diagnosis of early AHM, 133 digital dermoscopic images of lesions histopathologically diagnosed as amelanotic/hypomelanotic superficial spreading melanoma with ≤1 mm thickness (AHSSMs) (n = 27), amelanotic/hypomelanotic non-melanocytic lesions (AHNMLs) (e.g., seborrhoeic keratosis and basal cell carcinoma) (n = 79), and amelanotic/hypomelanotic benign melanocytic lesions (AHBMLs) (e.g., compound and dermal nevi) (n = 27), were dermoscopically assessed by three blinded dermatologists. Using multivariate analysis, we found a significantly increased risk of diagnosing AHSSM versus AHNML and AHBML when the lesion was characterized by the presence of more than one shade of pink (odds ratio [OR] 37.11), irregular dots/globules (OR 23.73), asymmetric pigmentation (OR 8.85), and structureless pattern (OR 7.33). In conclusion, dermoscopy may improve early AHM detection, discriminating AHSSM from amelanotic/hypomelanotic non melanoma lesions.

Erbium: YAG laser treatment efficacy and association with histologic features for giant congenital melanocytic nevi management.

Limited research exists on laser treatment of giant congenital melanocytic nevus (GCMN). We sought to elucidate the efficacy of the Erbium: YAG laser on GCMN and the histologic factors associated with a positive clinical response. Between 2019 and 2022, we enrolled 30 medium-to-giant CMN patients who underwent Er: YAG laser treatment. All patients received biopsies before and after laser treatments. Clinical efficacy outcomes were evaluated by the investigator's global assessment (IGA), 5-point scale of depigmentation, and Vancouver Scar Scale (VSS) scores at least 6 months after treatment. Of the 30 cases, 18 (60.0%) showed improvement (IGA score ≥3). Eight (26.7%) patients showed repigmentation. Eight (26.7%) patients developed hypertrophic scars. The average IGA, depigmentation, and VSS scores were 2.93, 3.57, and 3.20. The IGA score was higher (3.24 ± 1.18 vs. 2.22 ± 0.97, p = 0.031) and a lower repigmentation rate (14.3% vs. 55.6%, p = 0.032) was observed in the cases with Grenz zone. The IGA score was higher (3.33 ± 1.24 vs. 2.13 ± 0.89, p = 0.023) and the repigmentation rate was lower (11.1% vs. 50.0%, p = 0.034) also in the cases with the melanocytes nests with aggregation of melanin. Lesions with superficial ablation resulted in less hypertrophic scar formation than those with deep ablation (5.9% vs. 53.8%, p < 0.05). The Er: YAG laser demonstrated effective clinical results for GCMNs. The grenz zone and the melanocytes nests with aggregation of melanin are promising predictors of laser efficacy.

Thickness of melanocytes in giant congenital melanocytic nevus for complete surgical excision: clinicopathological evaluation of 117 lesions according to the area and size

BackgroundGiant congenital melanocytic nevi (GCMN) are usually defined as nevi that exceed 20 cm in maximal diameter or 15% of the total body surface area. There have been reports of life-long malignant change risks arising from GCMN, leading to surgical excision of GCMN. This study aims to evaluate the thickness of melanocytes based on clinical factors in order to provide objective information for the complete resection of the lesion.MethodsOverall, 75 patients diagnosed with GCMN between 2000 and 2021 were included, and their clinical records were collected retrospectively. 117 pathologic slides obtained during excision were reviewed to measure nevus thickness. Clinical factors were assessed with a generalized estimated equation model for association with nevus thickness.ResultsThe thickness of nevus was significantly associated with the location and size. Nevus thickness was more superficial in the distal extremity than in the head and trunk (P = 0.003 [head]; P < 0.001 [trunk]; P = 0.091 [Proximal extremity]). Nevi sized 60 cm or more were significantly deeper than those measuring 20–29.9 cm (P = 0.035). An interaction between size and location existed (P < 0.001). Trunk and distal extremity lesions consistently exhibited uniform thickness regardless of lesion size, whereas head and proximal extremity lesions showed variations in thickness based on lesion size.ConclusionGCMNs have differences in thickness according to location and size. Therefore, it is necessary to devise an approach optimized for each patient to treat GCMN.Mini-abstractIn the study, it was emphasized that the thickness of GCMN is correlated with clinical factors, specifically the location and size of the nevus. Consequently, these findings underscore the need for individualized treatment plans for effective surgical intervention.

Melanocytic nevus: Clinical features and colorimetrial evaluation

BACKGROUND: An increase in the frequency of registration of skin malformations, benign, precancerous and malignant skin neoplasms requires new approaches to their diagnosis and treatment. The different depth of melanocytic nevi in the epidermis and dermis is reflected in the color of the melanocytic nevus.&#x0D; AIM: to study the localization, size and intensity of pigmentation of melanocytic nevi depending on their color.&#x0D; MATERIALS AND METHODS: A clinical and instrumental study of 280 people with melanocytic nevi of various localization was conducted using their colorimetric assessment and dermatoscopic diagnosis. If melanoma was suspected, patients were consulted by an oncologist. The diagnosis of "melanoma" was confirmed histologically.&#x0D; RESULTS: Melanocytic nevi are more localized on the face than on the abdomen, back or chest, which is confirmed statistically. The largest sizes ― 5.5 mm ― are reached by nevi having a dark brown color, and, consequently, localized in the epidermis above the basal layer, and the smallest ― 2.0 mm ― melanocytic nevi with brown color located in the basal layer of the epidermis, which is also statistically confirmed.&#x0D; CONCLUSION: The largest sizes ― 5.5 mm ― are reached by nevi having a dark brown color, and, consequently, localized in the epidermis above the basal layer, and the smallest ― 2.0 mm ― melanocytic nevi with brown color located in the basal layer of the epidermis.

Spatial transcriptomic analysis of tumour-immune cell interactions in melanoma arising from congenital melanocytic nevus.

Studies on the interaction between tumour-infiltrating immune cells (TIICs) and tumour cells in melanoma arising from congenital melanocytic nevus (CMN) are lacking. The aim of this study was to determine the intratumoral immune landscape of TIICs and tumour cells during invasion and metastasis. Tissue specimens were obtained from patients with melanoma originating from CMN. Differential gene expression in melanoma cells and TIICs during invasion and metastasis was determined using spatial transcriptomics. As invasion depth increased, the expression of LGALS3, known to induce tumour-driven immunosuppression, increased in melanoma cells. In T cells, the expression of genes that inhibit T-cell activation increased with increasing invasion depth. In macrophages, the expression of genes related to the anti-inflammatory M2 phenotype was upregulated with increasing invasion depth. Compared to primary tumour cells, melanoma cells in metastatic lesions showed upregulated expression of genes associated with cancer immune evasion, including AXL and EPHA2, which impede T-cell recruitment, and BST2, associated with M2 polarization. Furthermore, T cells showed increased expression of genes related to immunosuppression, and macrophages exhibited increased expression of genes associated with the M2 phenotype. The interaction between melanomas arising from CMN and TIICs may be important for tumour progression and metastasis.

An approach to the dermatological classification of histopathological skin images using a hybridized CNN-DenseNet model.

This research addresses the challenge of automating skin disease diagnosis using dermatoscopic images. The primary issue lies in accurately classifying pigmented skin lesions, which traditionally rely on manual assessment by dermatologists and are prone to subjectivity and time consumption. By integrating a hybrid CNN-DenseNet model, this study aimed to overcome the complexities of differentiating various skin diseases and automating the diagnostic process effectively. Our methodology involved rigorous data preprocessing, exploratory data analysis, normalization, and label encoding. Techniques such as model hybridization, batch normalization and data fitting were employed to optimize the model architecture and data fitting. Initial iterations of our convolutional neural network (CNN) model achieved an accuracy of 76.22% on the test data and 75.69% on the validation data. Recognizing the need for improvement, the model was hybridized with DenseNet architecture and ResNet architecture was implemented for feature extraction and then further trained on the HAM10000 and PAD-UFES-20 datasets. Overall, our efforts resulted in a hybrid model that demonstrated an impressive accuracy of 95.7% on the HAM10000 dataset and 91.07% on the PAD-UFES-20 dataset. In comparison to recently published works, our model stands out because of its potential to effectively diagnose skin diseases such as melanocytic nevi, melanoma, benign keratosis-like lesions, basal cell carcinoma, actinic keratoses, vascular lesions, and dermatofibroma, all of which rival the diagnostic accuracy of real-world clinical specialists but also offer customization potential for more nuanced clinical uses.

The Keratinocyte in the Picture Cutaneous Melanoma Microenvironment.

Melanoma progression is a multistep evolution from a common melanocytic nevus through a radial superficial growth phase, the invasive vertical growth phase finally leading to metastatic dissemination into distant organs. Melanoma aggressiveness largely depends on the propensity to metastasize, which means the capacity to escape from the physiological microenvironment since tissue damage due to primary melanoma lesions is generally modest. Physiologically, epidermal melanocytes are attached to the basement membrane, and their adhesion/migration is under the control of surrounding keratinocytes. Thus, the epidermal compartment represents the first microenvironment responsible for melanoma spread. This complex process involves cell-cell contact and a broad range of secreted bioactive molecules. Invasion, or at the beginning of the microinvasion, implies the breakdown of the dermo-epidermal basement membrane followed by the migration of neoplastic melanocytic cells in the superficial papillary dermis. Correspondingly, several experimental evidences documented the structural and functional rearrangement of the entire tissue surrounding neoplasm that in some way reflects the atypia of tumor cells. Lastly, the microenvironment must support the proliferation and survival of melanocytes outside the normal epidermal-melanin units. This task presumably is mostly delegated to fibroblasts and ultimately to the self-autonomous capacity of melanoma cells. This review will discuss remodeling that occurs in the epidermis during melanoma formation as well as skin changes that occur independently of melanocytic hyperproliferation having possible pro-tumoral features.

Metabolomic analysis reveals the biological characteristics of giant congenital melanocytic nevi

Giant congenital melanocytic nevi (GCMN) is a congenital cutaneous developmental deformity tumor that usually occurs at birth or in the first few weeks after birth, but its pathogenesis is still unclear. In this study, nuclear magnetic resonance-based metabolomics strategy was employed to evaluate the metabolic variations in serum and urine of the GCMN patients in order to understand its underlying biochemical mechanism and provide a potential intervention idea. Twenty-nine metabolites were observed to change significantly in serum and urine metabolomes, which are mainly involved in a variety of metabolic pathways including glyoxylate and dicarboxylate metabolism, TCA cycle and metabolisms of amino acids. The substantial cores of all the disturbed metabolic pathways are related to amino acid metabolism and carbohydrate metabolism and regulate the physiological state of the GCMN patients. Our results provide the physiological basis and physiological responses of GCMN and will be helpful for better understanding the molecular mechanisms of GCMN in future research.

Eyelid Tumors at Razi and Farabi Hospitals, Tehran, Iran

Background: Eyelid tumors are common in the daily practice of skin tumors and are composed of benign and malignant lesions. Methods: This retrospective case series study collected histopathologic reports of eyelid tumors of patients treated between 2022 and 2023 in Razi and Farabi hospitals (Tehran, Iran). Patient data, including patient age, sex, location of the lesion, and recurrence, were collected. Descriptive and inferential statistics were used to characterize the subgroups. Results: The sample was composed of 154 eyelid tumor specimens, including 72 (47%) malignant cases, 80 (52%) benign cases, and 2 (1%) premalignant cases. Malignant tumors included 81.9% basal cell carcinomas (BCC), 15.3% basosquamous cell carcinomas (BSC), and 1.4% squamous cell carcinoma (SCC). The benign eyelid lesions were comprised of 20% intradermal melanocytic nevus, 11.3% epidermal cyst, 7.6% dermoid cyst, 10% seborrheic keratosis, 6.3% xanthelasma, 2.5% wart, 3.8% compound nevus, 5% fibroconnective tissue, 3.8% squamous papilloma, 3.8% neurofibroma, 2.5% comedone,2.5% apocrine hidrocystoma, 2.5% foreign body type granuloma, and 1.3% of others (arteriovenous hemangioma, cavernous hemangioma, cutaneous horn, etc.) The premalignant lesions were 2 cases of actinic keratosis. Benign lesions had an equal frequency of occurrence in the upper and lower lids. Malignant lesions were seen more in the lower lid. Premalignant lesions were seen in the lower lid. The mean age at diagnosis was 45.8 ± 23.06 years for patients with benign lesions and 63.5 ± 16.7 years for patients with malignant lesions. The mean age for patients with premalignant lesions was 81.5 ± 9.19 years (P &lt; 0.001). Conclusions: In our study, benign lesions were seen predominantly in young persons and malignant lesions were mostly seen in elderly persons. There is an equal occurrence of malignant lesions in males and females, and recurrence after excision was infrequent.

Review: Are moles senescent?

Melanocytic nevi (skin moles) have been regarded as a valuable example of cell senescence occurring invivo. However, a study of induced nevi in a mouse model reported that the nevi were arrested by cell interactions rather than a cell-autonomous process like senescence, and that size distributions of cell nests within nevi could not be accounted for by a stochastic model of oncogene-induced senescence. Moreover, others reported that some molecular markers used to identify cell senescence in human nevi are also found in melanoma cells-not senescent. It has thus been questioned whether nevi really are senescent, with potential implications for melanoma diagnosis and therapy. Here I review these areas, along with the genetic, biological, and molecular evidence supporting senescence in nevi. In conclusion, there is strong evidence that cells of acquired human benign (banal) nevi are very largely senescent, though some must contain a minor non-senescent cell subpopulation. There is also persuasive evidence that this senescence is primarily induced by dysfunctional telomeres rather than directly oncogene-induced.

Optimized self-attention based cycle-consistent generative adversarial network adopted melanoma classification from dermoscopic images.

Skin is the exposed part of the human body that constantly protected from UV rays, heat, light, dust, and other hazardous radiation. One of the most dangerous illnesses that affect people is skin cancer. A type of skin cancer called melanoma starts in the melanocytes, which regulate the colour in human skin. Reducing the fatality rate from skin cancer requires early detection and diagnosis of conditions like melanoma. In this article, a Self-attention based cycle-consistent generative adversarial network optimized with Archerfish Hunting Optimization Algorithm adopted Melanoma Classification (SACCGAN-AHOA-MC-DI) from dermoscopic images is proposed. Primarily, the input Skin dermoscopic images are gathered via the dataset of ISIC 2019. Then, the input Skin dermoscopic images is pre-processed using adjusted quick shift phase preserving dynamic range compression (AQSP-DRC) for removing noise and increase the quality of Skin dermoscopic images. These pre-processed images are fed to the piecewise fuzzy C-means clustering (PF-CMC) for ROI region segmentation. The segmented ROI region is supplied to the Hexadecimal Local Adaptive Binary Pattern (HLABP) to extract the Radiomic features, like Grayscale statistic features (standard deviation, mean, kurtosis, and skewness) together with Haralick Texture features (contrast, energy, entropy, homogeneity, and inverse different moments). The extracted features are fed to self-attention based cycle-consistent generative adversarial network (SACCGAN) which classifies the skin cancers as Melanocytic nevus, Basal cell carcinoma, Actinic Keratosis, Benign keratosis, Dermatofibroma, Vascular lesion, Squamous cell carcinoma and melanoma. In general, SACCGAN not adapt any optimization modes to define the ideal parameters to assure accurate classification of skin cancer. Hence, Archerfish Hunting Optimization Algorithm (AHOA) is considered to maximize the SACCGAN classifier, which categorizes the skin cancer accurately. The proposed method attains 23.01%, 14.96%, and 45.31% higher accuracy and 32.16%, 11.32%, and 24.56% lesser computational time evaluated to the existing methods, like melanoma prediction method for unbalanced data utilizing optimized Squeeze Net through bald eagle search optimization (CNN-BES-MC-DI), hyper-parameter optimized CNN depending on Grey wolf optimization algorithm (CNN-GWOA-MC-DI), DEANN incited skin cancer finding depending on fuzzy c-means clustering (DEANN-MC-DI). RESEARCH HIGHLIGHTS: This manuscript, self-attention based cycle-consistent. SACCGAN-AHOA-MC-DI method is implemented in Python. (SACCGAN-AHOA-MC-DI) from dermoscopic images is proposed. Adjusted quick shift phase preserving dynamic range compression (AQSP-DRC). Removing noise and increase the quality of Skin dermoscopic images.

Clinical and genetic determinants of vitamin D receptor expression in cutaneous melanoma patients.

Decrease of vitamin D receptor (VDR) expression is observed in melanocytic naevi and melanoma compared to normal skin. Little is known about factors influencing VDR expression in cutaneous melanoma (CM). We investigated the correlation of VDR expression in CM with 25-hydroxy vitamin D (25OHD) levels, demographic/clinical parameters, genetic variants of VDR and pathology of the primary tumor. Demographic/clinical parameters were recorded in 407 prospectively recruited CM patients of a multi-center controlled study (ViDMe trial). We determined VDR expression both in the nucleus and in the cytoplasm by semi-quantitative assessment in CM tissue using histochemistry in 279 patients, expressed in percentages and histoscore (H-score). Genomic DNA from 332 patients was extracted to genotype thirteen VDR single nucleotide polymorphisms (SNPs) using TaqMan. VDR expression in CM tissue from 279 patients was correlated with clinical/demographic parameters and 25OHD levels (univariable and multivariable analysis), VDR SNPs (univariable analysis) and pathology parameters of primary CM tissue (univariable analysis). Cytoplasmic VDR expression was increased in patients who stated to have a high sun exposure during their life compared to patients with low sun exposure (p H-score,univariable : 0.001, p H-score,multivariable : 0.004). The A allele of the genetic VDR polymorphism Fok1 was associated with a higher expression of the VDR in the cytoplasm (p cytoplasmic, univariable : 0.001 and p H-score, univariable : 0.02). In the primary tumor, presence of mitosis (p nucleus,%, univariable : 0.002) and perineural invasion (p nucleus,%,univariable : 0.03) were significantly associated with low nuclear VDR expression. ClinicalTrials.gov Identifier: NCT01748448.

Preliminary analysis of the melanoma multimedia educational program for general practitioners on behalf of the Italian Melanoma Intergroup.

According to the National Oncological Plan 2023-2027 on the importance of multidisciplinary and interactive e-learning training, the Italian Melanoma Intergroup (IMI) has developed MelaMEd (Melanoma Multimedia Education), a national project for general practitioners (GPs) on the prevention and detection of cutaneous melanoma through an online platform and an online course. MelaMEd enables participants to i) recognize skin lesions that require specialist dermatological assessment, ii) select patients at high risk of melanoma and iii) be informed of the diagnosis and treatment pathway of patients with melanoma. A free online platform and online course were developed and launched in June 2022. Before starting the course, enrolled participants fill out a pre-training questionnaire concerning the basic knowledge of the disease and the recognition and management of suspicious lesions. After the course, participants will fill out the same questionnaire again. The online course will end in December 2023. Here we present a preliminary analysis of the pre-training results (January 2023-July 2023). The data have been analyzed descriptively. So far, five healthcare centers have participated in the project for a total of 1320 participants. Of these, 298 compiled the pre-training questionnaire. Forty-seven percent of them were aged <40 years. Respondents were almost divided between GPs (47%) and resident GPs (48%). Among the theoretical questions, the ABCDE rule and ugly duckling sign are well known (96% and 91% of correct answers, respectively), but a lower percentage (68%) of respondents knows the EFG rule for the recognition of nodular melanomas and the statement of Breslow thickness (29%). Regarding the series of clinical images of pigmented skin lesions and their management, the percentages rate of accuracy varied from 33% to 87%: melanoma (5 cases) ranges from 36% to 71%, melanocytic nevi (3 cases) from 33% to 84%, whereas the percentages rate of referral for dermatological evaluation varied from 44% to 99%. Melanoma cases referred to dermatologist ranges from 67% to 99%. This preliminary analysis on pre-train-ing questionnaire mainly showed a lack of knowledge of the two major points of melanoma diagnosis (EFG) and management (Breslow thickness), as well as a low rate of participants. We will compare the proportions of correct answers to the questionnaires before and after the course once available.

KISSING NEVUS RECONSTRUCTION WITH A SUPRACLAVICULAR GRAFT: A RARE CASE REPORT

Introduction : Kissing nevus is a rare form of congenital nevus that occurs on upper and lower eyelid of one eye, forming a large nevus when the eyelids are closed. This condition causes functional and aesthetic problems thus the reconstruction is essential.&#x0D; Case Illustration : A 23-years old female presented to our ophthalmology outpatient clinic with complain of having painless, black colored, non-progressive nevus over left upper and lower eyelids since birth that cosmetically unpleasing. The dark brown-black colored was sized 55x30 mm with hypertrichosis covering approximately two third of both left upper and lower eyelid margins and extending to cheek. The entire nevus was excised and reconstructed by supraclavicular full thickness skin graft, lateral canthopexy and canthoplasty. Three weeks after operation showed satisfactory results. Histological examination revealed intradermal nevus pigmentosus.&#x0D; Discussion : The reconstruction of eyelid after excision remains a challenge because of its specialized function and cosmetic significance. Ideally, the reconstruction should provide a stable eyelid margin, protect the ocular surface, and sustain mobility. Free skin grafts harvested from the control lateral eyelid, postauricular, supraclavicular, and upper arm region have been the most common reconstructive approach. The supraclavicular area is a reliable donor option to cover large head and neck defects due to its similarity in colour, thickness, and flexibility.&#x0D; Conclusion : Free supraclavicular graft is safe, reliable and cosmetically acceptable choice for reconstruction head and neck defects.

Commentary on “Dermoscopic-Guided Shave Removal of Acquired Facial Melanocytic Nevi in Dark-Skinned Individuals”

Commentary on “Dermoscopic-Guided Shave Removal of Acquired Facial Melanocytic Nevi in Dark-Skinned Individuals”

Dermoscopic-Guided Shave Removal of Acquired Facial Melanocytic Nevi in Dark-Skinned Individuals.

Acquired melanocytic nevi are common benign skin lesions that require removal under certain circumstances. Shave removal is a straightforward treatment modality with a risk of recurrence. To evaluate the outcome of dermoscopy-guided shave removal of acquired melanocytic nevi in the face of dark-skinned individuals who are more liable to postsurgical complications. The study was conducted on 64 patients with acquired facial melanocytic nevi. Serial shave removal using a razor blade guided by dermoscopic examination was done until nevus-free tissue was seen, followed by electrocauterization of the base. Cosmetic outcome, patients' satisfaction, and recurrence rate were evaluated during follow-up. Excellent cosmetic outcome was achieved in 54.69% of patients, while 39.06% had an acceptable outcome, and 6.25% of patients had poor cosmetic outcome. Meanwhile, the recurrence rate was noticed in 5 cases only (7.8%). Dermoscopic-guided shave removal provides an easy procedure of treating common melanocytic nevi with an acceptable cosmetic result and a lower rate of recurrence even in patients with darker skin phenotypes.

Comparison of S100A8 and PRAME as biomarkers fordistinguishing melanoma from melanocytic naevus: acase-control analysis.

S100A8 is a melanoma biomarker expressed in the melanoma-associated epidermal keratinocytes, but its diagnostic utility has not been compared with other biomarkers, including PRAME. To compare the utility of S100A8 and PRAME immunohistochemistry (IHC) in the differential diagnosis of melanoma and naevi in a case-control study. A previously described cohort of 209 melanomas (case samples) and naevi (control samples) dual-immunostained for S100A8 and PRAME were included. For S100A8, previously reported scores indicating the proportion of tumour-associated epidermis stained (0 = indeterminate; 1 = 0-4%; 2 = 5-25%; 3 = 26-50%; 4 = 51-75%; 5 = > 75%) were utilized. PRAME IHC was reviewed by at least two reviewers and a consensus score assigned, with score indicating the proportion of tumour stained (0 = indeterminate; 1 = 0%; 2 = 1-50%; 3 = > 50%). A positive test was defined as > 50% staining. The area under the receiver operating characteristic curves for S100A8 (0.833) and PRAME (0.874) were not significantly different from each other (P = 0.22). The diagnostic sensitivity and specificity were 42.4% [95% confidence interval (CI) 32.6-52.8%] and 98.2% (95% CI 93.6-99.8%) for S100A8, and 79.8% (95% CI 70.5-87.2%) and 87.3% (95% CI 79.6-92.9%) for PRAME, respectively. A combined test requiring both S100A8 and PRAME IHC positivity had a sensitivity of 39.4% (95% CI 29.7-49.7%) and specificity of 99.1% (95% CI 95.0-100.0%). S100A8 and PRAME have utility in the diagnostic workup of melanoma, with S100A8 being more specific and PRAME being more sensitive when using this threshold. Our findings suggest that these two immunohistochemical markers may favourably complement one another to improve the detection of melanoma.

Clinical Misdiagnosis of Cutaneous Malignant Tumors as Melanocytic Nevi or Seborrheic Keratosis: A Retrospective Analysis of a Chinese Population.

The rising incidence and mortality associated with cutaneous malignant tumours highlight the importance of early diagnosis of these tumors. In clinical practice, these tumors are often misdiagnosed as benign skin lesions such as melanocytic nevi (MN) and seborrheic keratosis (SK) because of their similar morphologic features. The incidence and clinicopathological subtypes of cutaneous malignancies in East Asia populations significantly differ from those in fair-skinned groups. However, studies on misdiagnoses in Eastern countries are lacking. Therefore, this study focused on the clinical and pathological features of cutaneous malignant tumors misdiagnosed as MN or SK in a Chinese population. A total of 4592 samples clinically diagnosed as MN (n = 3503) or SK (n = 1089) from July 2014 to June 2022 were collected and evaluated retrospectively. The clinical and pathological data were analyzed to identify associated factors. Pathological assessments showed that 2.5% (86/3503) of the specimens clinically diagnosed as MN were malignancies, predominantly basal cell carcinoma (BCC, 84.9%, 73/86), followed by malignant melanoma (MM, 8.1%, 7/86) and squamous cell carcinoma (SCC, 7.0%, 6/86). Similarly, 5.7% (62/1089) of the specimens clinically diagnosed as SK were malignant tumors, of which BCC (50.0%, 31/62) was the most common, followed by SCC (41.9%, 26/62) and MM (8.1%, 5/62). In both types of specimens, advanced age and facial lesions were risk factors for malignancy misdiagnosis. The malignancy rate, mean age, and proportion of SCC in the specimens clinically diagnosed as SK were higher than those in the specimens clinically diagnosed as MN. Dermoscopy significantly reduced the rate of misdiagnosis of these tumors as MN or SK. In China, cutaneous malignant tumors misdiagnosed as MN or SK are not uncommon in clinical practice, and active introduction of noninvasive diagnostic techniques is essential to distinguish them.

Perineural differentiation in neurotized nevi

BackgroundPerineuriomatous melanocytic nevi are rare and this may indicate the similar embryological source of melanocytes and peripheral nerves in the neural crest. Neurotized melanocytic nevi may resemble nerve sheath tumors histologically, and show schwannian differentiation. However, literature on whether neurotized nevi differentiate into perineural cells is controversial. We examined our cases of neurotized nevi for evidence of perineural differentiation. Materials and methodsA total of 100 benign nevi with large neurotized component (microscopically involved a low power field 4.2 mm in diameter) were prospectively evaluated in excisional biopsy samples. Immunohistochemical stainings for EMA, Claudin1, Glut1 and neurofilament were performed. ResultsPerineural differentiation was immunohistochemically detected in the neurotized component of the nevi in 61% of the cases with EMA and in all the cases with Glut1 and Claudin1. Axonal differentiation was not detected with neurofilament. The expression pattern, especially with Glut1, was usually in form of partial or complete staining surrounding the Meissner's corpuscle-like structure (MCLS). Also, a linear/curvilinear staining pattern was observed particularly with Claudin1. A diffuse staining pattern with EMA, Glut1 and Claudin1 was detected in a case with a microscopically distinct whorl structure, and in which spindle cells are separated from the superficial epithelioid melanocytes with an abrupt transition histologically. These findings of the case are compatible with previous reports of perineuromatous nevus. ConclusionPerineural differentiation is not uncommon and immunohistochemically observed in all nevi with a relatively large component of neurotization. To prevent misdiagnosing desmoplastic melanoma and overtreating patients, it is crucial to be aware of perineuromatous nevi.