BACKGROUND: Melanocytic nevi typically appear in early childhood, and their removal is a common plastic surgery procedure performed on children. However, the epidemiological characteristics and hospitalization burden of children with melanocytic nevi have rarely been described in detail.
METHODS: Medical records of pediatric inpatients with melanocytic nevi from January 1, 2016, to December 31, 2021, were collected from the Futang Research Center of Pediatric Development database in China. We then extracted and statistically analyzed the relevant information, including demographic characteristics, clinical information, hospitalization burden, and other basic information for each inpatient.
RESULTS: Among the 13,396 inpatients with melanocytic nevi, the highest number of cases was found in East China, and most patients were residents of urban areas. Most hospitalized patients consisted of boys aged 7-12 years with melanocytic nevi. Lesion sites in the buttocks and lower limbs were most common among pediatric inpatients with melanocytic nevi. Compound nevi were the most common (38.50 %) histological subtype and the rate of conversion into melanoma was 1.02 % (137 inpatients) among pediatric inpatients with melanocytic nevi. The hospitalization burden for patients varied significantly based on factors such as the age of the patients undergoing surgery, year of hospitalization, site of the lesion, histological subtype, and surgical method. In general, if the patients\' age was under 1 year, lesion site was located in face, and there was a need for excision combined with tissue expander can significantly increase the treatment fees for pediatric inpatients with melanocytic nevi.
CONCLUSIONS: Given the increasing number and relatively large hospitalization burden among children with melanocytic nevi hospitalized in China, the government needs to pay more attention to this group and provide corresponding economic and policy support.

This study investigates the differential expression of miRNA gene subtypes in tumoral versus benign nevi in individuals with melanoma, aiming to identify clinically significant correlations that could serve as reliable markers for assessing tumor stage and progression. Conducted between 2019 and 2022, this descriptive, quantitative observational research analyzed 90 formalin-fixed paraffin-embedded (FFPE) samples from the Pius Brinzeu County Emergency Clinical Hospital, Timisoara, including 45 samples of advanced-stage melanoma and 45 samples of pigmented nevi. miRNA purification and analysis were performed using the miRNeasy Kit and the Human Cancer PathwayFinder miScript miRNA PCR Array, with statistical analysis (including logistic regression) to determine associations with cancer staging, such as high Breslow index risk, number of mitoses, and vascular invasion. After the analysis and comparison of 180 miRNA gene subtypes, we selected 10 of the most upregulated and 10 most downregulated genes. The results revealed that hsa-miR-133b, hsa-miR-335-5p, hsa-miR-200a-3p, and hsa-miR-885-5p were significantly upregulated in melanoma samples, with fold changes ranging from 1.09 to 1.12. Conversely, hsa-miR-451a and hsa-miR-29b-3p showed notable downregulation in melanoma, with fold changes of 0.90 and 0.92, respectively. Additionally, logistic regression analysis identified hsa-miR-29b-3p (OR = 2.51) and hsa-miR-200a-3p (OR = 2.10) as significantly associated with an increased risk of a high Breslow index, while hsa-miR-127-3p and hsa-miR-451a were associated with a reduced risk. Conclusively, this study underscores the significant alterations in miRNA expression in melanoma compared to benign nevi and highlights the potential of specific miRNAs as biomarkers for melanoma progression. The identification of miRNAs with significant associations to melanoma characteristics suggests their utility in developing non-invasive, cost-effective diagnostic tools and in guiding therapeutic decisions, potentially improving patient outcomes in melanoma management.

BACKGROUND: Acral melanoma (AM) is the most common subtype of malignant melanoma in China, with a very poor prognosis. Despite the frequent reporting of trauma events in AM cases, the precise etiology of AM remains elusive.
METHODS: A retrospective analysis was conducted on a cohort of 303 AM patients at Nanjing Drum Tower Hospital. The patients were categorized into four distinct groups based on different patterns of disease onset: trauma type (Type 1), pigmented nevus type (Type 2), pigmented nevi with trauma (Type 3), and pigmented nevi with natural ulceration (Type 4). Differences in clinicopathological features, genetic alterations, and tumor immune microenvironment (TIME) were analyzed.
RESULTS: Traumatic events accounted for a large proportion of AM cases. Among these categories, Type 1 patients displayed the least favorable pathological traits and an immunosuppressive TIME. Common copy number variations (CNVs) were observed in CCND1, RB1, FGF19, and IL7R, while CNVs in CDK4 and TERT occurred less frequently in patients with a history of trauma (Type 1 and Type 3). Type 2 patients exhibited the most favorable pathological characteristics and genetic profiles, and demonstrated the lowest incidence of CCDN1 and RB1 CNVs but had the highest CDK4 CNVs. In contrast, the pathological behavior of Type 3 and Type 4 patients was in between Type 1 and Type 2. And patients in Type 3 and Type 4 displayed a more favorable overall microenvironment.
CONCLUSIONS: This study provides a clinical classification of Chinese AM based on diverse clinical onset characteristics and highlights the important role of trauma in AM. These findings may help to guide the diagnosis, treatment, and prognosis of AM patients. Further investigations are imperative to elucidate the underlying mechanisms governing the association between trauma and AM.

Spitz tumors are a subset of melanocytic neoplasms characterized by epithelioid or spindled melanocytes(1). The benign nature of the \"Spitz nevus\" has since been clarified, but the debate regarding Spitzoidtumors (STs) is still ongoing. Spitzoid tumors encompass a wide spectrum of cutaneous lesions ranging from benign Spitz nevus (SN) to Spitzoid melanoma (SM), the latter displaying capacity for widespread metastasis and a potentially lethal outcome (2). The term atypical Spitz tumors (ASTs) refers to melanocytic tumors exhibiting the morphological features of SN, as well as some features associated with malignancy, but not sufficient to classify them as SMs. Currently, histopathology is the gold standard for the diagnosis of STs and cutaneous MM. However, the differential diagnosis between benign and malignant melanocytic lesions with spitzoid features remains challenging (3-6). In order to facilitate the work of clinicians and pathologists, we attempted a comparative clinical and demographic study comparing ASTs and MMs of patients referred to two Italian institutes. Patient data were obtained from two different Italian dermatological centers (Melanoma Registry of the Instituto Dermopaticodell\'Immacolata IDI-IRCCS Rome, Lazio and the Skin Cancer Unit of Dermatology, Hospital Sant\'Orsola-Malpighi, University of Bologna), from January 2007 to December 2017. Histological reports presenting pre-operative queries of both \"atypical Spitz nevi\" or \"malignant melanoma\" and a final diagnosis confirming one of the queries were included in the study. The chi-square test or Mann-Whitney U-test were applied to analyze differences between the groups for categorical variables such as sex, diagnosis, and continuous variables (age). The \"anatomic site\" variable was classified into three categories as follows: the limbs, trunk, and head/neck. A multivariate binary logistic model was used to investigate if the anatomic site was an independent predictor of MM. Age and sex were considered confounding factors. A total of 504 patients (51.8% men; 48.2% women) met the inclusion study criteria (mean age 52 years, SD = 22.8) (Table 1). 373 were cases of MM and 131 were cases of AST. Mean age of MM cases and AST were 61.2 years old (SD = 17.6) and 25.8 years old (SD = 13.8), respectively. Subjects with MM were predominantly men (58.2% versus 33.6%) (P<0.0001) and older (median age 62 years versus 25 years) (P=0.0001) than subjects with AST. The most frequent anatomic site for MM was the trunk (39.7 %), while the lower limb was the most frequent anatomic site for AST (48.1 %) (P<0.0001). Table 2 shows the multivariable analysis used to assess if anatomic site was an independent predictor of cutaneous melanoma. Multivariate analysis confirmed an increased risk for MM in comparison with AST for both localization on the trunk (OR:2.78; 95 %CI: 1.74-4.45) (P<0.0001) and head/neck (OR:3.20; 95% CI: 1.60-6.38) (P=0.0001). After introducing age (model 1, OR: 2.11; 95% CI: 1.08-4.12) (P=0.003) and sex into the model, the only anatomic site that remained statistically significant was the trunk (model 2, OR: 2.03; 95% CI: 1.0.3-3.99) (P=0.04). The results show that if the lesion was located on the trunk, the probability of being a MM was two times higher than that of AST, independent of sex, age, or center. After stratifying for sex, the effect was stronger for women (OR: 2.72; 95% CI: 1.14-6.50). After stratifying for age, the effect was stronger for younger subjects (<40 years) (OR: 2. 59; 95% CI: 1.20-5.60) (P=0.02). In this study, we focused on the clinical-epidemiological data in an attempt to improve the identification of nodular melanocytic lesions by providing clinicians with further information in order to reduce the rate of misdiagnosis and assist in providing critical clinical information to surgeons and pathologists. Consistently with the literature, ASTs were mainly found in young-adult patients (mean age was 25.8 years), in the female sex (66.4%), and were typically located on the lower limbs (48.1%) (3,7-10). MM were found to be slightly more common in male patients (58.2%) in the overall patient group; the mean age at the time of the diagnosis was 61.2 years old, and the majority of lesions were located on the trunk (39.7%). These data were similar to those reported by other authors (11-13). ASTs cases were mainly women and younger than MM cases, and were typically located on the lower limbs (Figure 3 and Figure 4). Nodules located on the trunk resulted in a two times greater risk of MM in comparison with AST. In summary, distinguishing ASTs from MMs is often challenging, and histopathology remains the diagnostic gold standard for melanocytic neoplasms, but a specific clinical framework may help surgeons, pathologists, and clinicians to correctly diagnose and manage these lesions in children and adults.

The prevalence of choroidal naevi is common and has been found to be up to 10%. Little is known regarding the optical properties of choroidal naevi. A novel hyperspectral eye fundus camera was used to investigate choroidal naevi\'s optical density spectra in the retina.
In an ophthalmology clinic setting, patients with choroidal naevi were included in the study. Visual acuity and pressure were tested. Following mydriatics, optical coherence tomography and fundus photography were taken as a reference, after which a hyperspectral image with 12 nm spectral resolution at 450-700 nm was taken. The optical density spectra was measured across the area of the naevus.
Nine patients with 11 naevi were examined. The visual acuity was not affected by any of the naevi. All the naevi were flat as measured either with the optical coherence tomography and/or on inspection, and only one naevi had a risk factor (orange pigmentation). The Wasserstein distance between the background and the naevi was higher at 695 nm compared to 555 nm (p = .002). The naevi could be grouped into three clusters based on the extracted optical density spectra.
Choroidal naevi are better visible in longer wavelengths compared to shorter wavelengths. This finding can be used to contour and follow choroidal naevi. Choroidal naevi expose different optical density spectra that can be grouped into three different clusters. One of these clusters has an optical density spectra resembling the absorption spectra of lipofuscin, which may indicate the content of this pigment.

BACKGROUND: NA OBJECTIVE: Evaluate the safety and feasibility of platelet-rich plasma (PRP) in the treatment of giant congenital melanocytic nevi (GCMN) in children with human acellular dermal matrix (HADM) transplantation.
METHODS: A total of 22 children with GCMN were included in the study. They were divided into an experimental and a control group. The experimental group used the method of HADM with Razor Autologous Skin Graft combined with PRP to repair skin and soft tissue defects after giant nevus resection (Group A, n = 11). The control group was treated with HADM with Razor Autologous Skin Graft (Group B, n = 11) only. To compare the survival rate of skin grafts, we used the Vancouver Scar Scale (VSS) for the postoperative skin graft area and the Patient and Observer Scar Assessment Scale (POSAS) to compare the two groups of patients.
RESULTS: There was no statistically significant difference in age, gender, location of giant nevi, and pathological classification between Group A and Group (P > 0.05). The survival rate of skin grafting and the VSS and POSAS scores of scar tissue in group A were superior to those of group B (P < 0.05).
CONCLUSIONS: PRP has improved the survival rate of composite skin grafting in children with GCMN, and long-term satisfactory prognosis of scar healing. Therefore, we consider this treatment method a valuable contribution to clinical practice.

A collision tumour (CT) is a neoplastic lesion comprised of two or more distinct cell populations that maintain distinct borders. Mostly, these are incidental findings in skin biopsies, whose pathologic mechanism and prevalence remain unknown, with few references among literature. Here, we present a retrospective study of CT, diagnosed by a dermatopathologist in our hospital between 2019-2022. Lesions have been defined individually and organized into three categories: benign-benign (BB), benign-malignant (BM) and malignant-malignant (MM). A total of 108 CT were diagnosed (1,4% of the biopsies from the dermatopathologist during this period), from which BM was the most frequent collision (48,5%). Globally, basal cell carcinoma (BCC) was the main malignant lesion and melanocytic nevus (MN) the main benign lesion. We have used the software Stata 14.2 in order to analyse results, and we have detected a statistically significant difference between age and collision type.

Dysplastic nevi represent one of the least agreed-upon entities in dermatopathology despite the existence of established criteria. This study explores preferentially expressed antigen in melanoma (PRAME) in dysplastic nevi, an uncharted area. We examined 22 common melanocytic nevi (CMN), 20 cutaneous melanomas (CM), 48 low-grade dysplastic nevi (LG-DN), and 40 high-grade dysplastic nevi (HG-DN). PRAME was immunohistochemically assessed using a five-tiered system (0 to 4 +). Among CMN, 59% scored 0, 32% scored 1 + , and 9% scored 2 + . CM had score 2 + and 4 + in 11% and 89% of cases, respectively. Among LG-DN, 38% presented score 0, 31% score 1 + , 17% score 2 + , 8% score 3 + , and 6% score 4 + . Thirty per cent of HG-DN demonstrated a score 0, 30% with score 1 + , 15% score 2 + , 10% score 3 + , and 15% score 4 + . Compared to CMN and CM, LG-DN and HG-DN showed heterogeneous expression profiles of PRAME. PRAME positivity effectively distinguished HG-DN from CM with 85% specificity and 80% sensitivity (p < 0.0001). Predictive values were 87% (negative) and 76% (positive). Furthermore, a trend of increased PRAME expression from LG-DN to HG-DN was observed. However, the applicability of PRAME in the differential diagnosis of dysplastic lesions remains unclear as can yield conflicting results with morphology, which remains the primary diagnostic tool for melanocytic lesions.

BACKGROUND: The early diagnosis of acral lentiginous melanoma (ALM) contributes to clinical outcomes since ALM can be mistaken for acral melanocytic nevus (AMN). ALM occurrence is reported to correlate with stress-bearing areas, which may assist in differential diagnoses. Our objective is to evaluate the distribution patterns of ALMs and AMNs on the palms and soles among Taiwanese patients.
METHODS: A retrospective analysis was performed by reviewing the charts of 1400 patients diagnosed with benign and malignant pigmented lesions confirmed after excisional biopsy at our institution between 2000 and 2022 in Taiwan. Correlations between lesions and clinicopathological factors were analyzed.
RESULTS: 309 AMNs and 177 ALMs were included. Mechanical stress was significantly associated with plantar ALMs (weight-bearing area: 92.65 %, arch: 7.35 %, P < 0.001). Significant differences in the distribution patterns were observed for plantar ALMs compared with all AMNs (P < 0.001) and non-atypical AMNs (P < 0.001), but were not observed between palmar AMNs and ALMs.
CONCLUSIONS: Plantar ALMs were most commonly observed on the weight-bearing areas of the soles, distinct from the distribution of all AMNs and of non-atypical AMNs. The distribution features and anatomic mapping of ALMs may facilitate the early clinical diagnosis of ALM.

BACKGROUND: Incidence of cutaneous melanoma is steadily growing, and its early recognition is of paramount importance. Small, pigmented lesions often represent a challenge for the clinician, as predictors of melanoma have not yet been uniquely identified in this setting.
OBJECTIVE: To identify dermoscopic features that aid in distinguishing small diameter melanomas (≤5 mm) from equivocal melanocytic nevi measuring ≤5 mm.
METHODS: A retrospective multicenter study was conducted to collect demographics, clinical and dermoscopic pictures of (i) histology-proven flat melanomas, measuring ≤5 mm, (ii) histology-proven but clinically/dermoscopically equivocal melanocytic nevi measuring ≤5 mm, and (iii) histology-proven flat melanomas, measuring >5 mm. An independent dermoscopic evaluation was performed. Differences in predefined dermoscopic features were assessed across the three groups.
RESULTS: A total of 103 melanomas measuring ≤5 mm were collected; 166 control lesions, comprising 85 large (>5 mm) melanomas and 81 dubious, clinically equivocal melanocytic nevi measuring ≤5 mm were included. Of the 103 mini-melanomas, only 44 were melanoma in situ. Five dermoscopic predictors of melanoma were identified for the assessment of flat, non-facial melanocytic lesions measuring ≤5 mm, namely: atypical pigment network, blue-white veil, pseudopods, peripheral radial streaks, and presence of more than one color. The latter were combined into a predictive model capable of identifying melanoma with 65% sensitivity and 86.4% specificity, at a cut-off score of 3. Among melanomas measuring ≤5 mm, presence of a blue-white veil (P = 0.0027) or negative pigment network (P = 0.0063) was associated with invasiveness.
CONCLUSIONS: A set of five dermoscopic predictors of melanoma, atypical pigment network, blue-white veil, pseudopods, peripheral radial streaks, and presence of more than one color is proposed for the assessment of flat, non-facial melanocytic lesions measuring ≤5 mm.