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Background: Giant 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. Methods: Overall, 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. Results: The 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. Conclusion: GCMNs have differences in thickness according to location and size. Therefore, it is necessary to devise an approach optimized for each patient to treat GCMN. In 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. [ABSTRACT FROM AUTHOR]

Congenital melanocytic nevus of the eyelid, also known as the "panda nevus of the eyelid," is a rare presentation of a congenital nevus. It presents as a divided lesion over the upper and lower eyelids. We describe a case of a 25-yearold female who presented to us with this lesion over the right upper and lower eyelids who underwent surgical excision with a full-thickness graft for the residual defect. [ABSTRACT FROM AUTHOR]

Copyright of Der Hautarzt is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Turkiye Klinikleri Journal of Dermatology is the property of Turkiye Klinikleri and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: To investigate the application and challenge of reflectance confocal microscopy (RCM) in the diagnosis of pigmented nevus. Method: A total of 997 patients with clinical diagnosis of pigmented nevus were included in the study, and RCM imaging was performed on the lesion of each patient. A biopsy was performed in 78 of these patients for histological diagnosis. We retrospectively analyzed the results of RCM diagnosis and histological diagnosis and then found the RCM characteristics of the histologically confirmed lesion. Results: According to the RCM images, 823 of the 997 (82.55%) patients were diagnosed with pigmented nevus, while 113 (11.33%) were not diagnosed by dermatologists using RCM. Of the 78 biopsy lesions, 36 of the 46 (78.26%) cases diagnosed with pigmented nevus were consistent with histological diagnosis, while three were rediagnosed with dermatofibromas, four were seborrheic keratosis, one was malignant melanoma in situ, and two were lentigo. Conclusion: RCM exhibits a high diagnostic accuracy for patients with clinical diagnosis of pigmented nevus. However, due to the limitation of RCM scanning depth and the commonality of the microscopic characteristics of related diseases, RCM still faces certain challenges in the diagnosis of pigmented nevus. [ABSTRACT FROM AUTHOR]

The value of dermoscopy in the detection of skin cancer is well established. Less is published on the utility of dermoscopy in the evaluation of pediatric skin disease. Our review (in two parts) aims to serve as an update on pediatric dermoscopy and to provide readers with a practical application for the use of dermoscopy in pediatric dermatology clinics. In part I, we propose a dermoscopy algorithm for pediatric skin disease and melanocytic growths, and in part II, we address vascular growths, common skin infections, and inflammatory conditions for which dermoscopy is valuable. [ABSTRACT FROM AUTHOR]

Background: Skin cancer is one of the most common forms of cancer in the world and melanoma is the deadliest type of skin cancer. Both melanoma and melanocytic nevi begin in melanocytes (cells that produce melanin). However, melanocytic nevi are benign whereas melanoma is malignant. This work proposes a deep learning model for classification of these two lesions. Methods: In this analytic study, the database of HAM10000 (human against machine with 10000 training images) dermoscopy images, 1000 melanocytic nevi and 1000 melanoma images were employed, where in each category 900 images were selected randomly and were designated as the training set. The remaining 100 images in each category were considered as the test set. A deep learning convolutional neural network (CNN) was deployed with AlexNet (Krizhevsky et al., 2012) as a pretrained model. The network was trained with 1800 dermoscope images and subsequently was validated with 200 test images. The proposed method removes the need for cumbersome tasks of lesion segmentation and feature extraction. Instead, the CNN can automatically learn and extract useful features from the raw images. Therefore, no image preprocessing is required. Study was conducted at Shahid Beheshti University of Medical Sciences, Tehran, Iran from January to February, 2020. Results: The proposed model achieved an area under the receiver operating characteristic (ROC) curve of 0.98. Using a confidence score threshold of 0.5, a classification accuracy of 93%, sensitivity of 94%, and specificity of 92% was attained. The user can adjust the threshold to change the model performance according to preference. For example, if sensitivity is the main concern; i.e. false negative is to be avoided, then the threshold must be reduced to improve sensitivity at the cost of specificity. The ROC curve shows that to achieve sensitivity of 100%, specificity is decreased to 83%. Conclusion: The results show the strength of convolutional neural networks in melanoma detection in dermoscopy images. The proposed method can be deployed to help dermatologists in identifying melanoma. It can also be implemented for self diagnosis of photographs taken from skin lesions. This may facilitate early detection of melanoma, and hence substantially reduce the mortality chance of this dangerous malignancy. [ABSTRACT FROM AUTHOR]

Neurofibromatosis type 1 (NF1) is a genodermatosis caused by heterozygous germ line variations in the NF1 gene. A second‐hit NF1 aberration results in the formation of café‐au‐lait macules, cutaneous neurofibroma and plexiform neurofibroma (PNF). Mosaic NF1 (mNF1), caused by a postzygotic NF1 mutation, is characterized by localized or generalized NF1‐related manifestations. Although NF1 and mNF1 are associated with pigmentary skin lesions, clinically recognizable melanocytic nevi that developed over PNF have not been reported. Here, we report the first case of multiple melanocytic nevi that developed on a giant café‐au‐lait macule and PNF. The PNF had biallelic NF1 deletions, a whole deletion of NF1 and a novel intragenic deletion involving exons 25–30. The deletions were not detected in the blood, which resulted in the diagnosis of mNF1. Furthermore, the nevus cells had not only biallelic NF1 deletions but also NRAS Q61R, a common mutation found in congenital melanocytic nevi. These analyses revealed the coexistence of the two different mosaic diseases, mNF1 and congenital melanocytic nevi. For a diagnosis of cases with atypical NF1‐like symptoms, genetic analyses using blood and lesional tissues are useful and aid in genetic counseling. [ABSTRACT FROM AUTHOR]

Background: Long‐pulsed (LP) lasers at pulse durations of 1‐300 ms have been used to destroy nests of nevi cells by selectively targeting pigment chromophores. Objective: To evaluate dual‐wavelength LP laser‐induced tissue reactions. Methods: The patterns of LP 755‐nm alexandrite (Alex) and/or 1064‐nm neodymium (Nd):yttrium‐aluminum‐garnet (YAG) laser‐induced tissue reactions were macroscopically evaluated using a tattoo‐embedded phantom. Additionally, a pilot in vivo human study was performed for common acquired melanocytic nevus, of which dermoscopic images and high‐speed cinematographs were obtained. Results: Combinations of Nd:YAG and Alex laser treatments at interpulse intervals of 10 or 20 ms generated round to oval zones of photothermal and photoacoustic injury in two distinctive areas containing disintegrated tattoo particles. Treatment at interpulse intervals of 10 or 20 ms between Alex and Nd:YAG pulses elicited lesser degrees of thermal damage to surrounding tissues, compared to treatment at 100 or 200 ms. Immediately after combined LP laser treatment of human nevus lesions in vivo, Nd:YAG‐Alex treatment at a 20‐ms interpulse interval exhibited more remarkable crusting and erosive appearances than Alex‐Nd:YAG treatment. Conclusion: For treating pigmented disorders, sequential delivery of LP Nd:YAG and Alex pulses at short interpulse intervals of 10‐20 ms can effectively destroy nests of pigment chromophores. [ABSTRACT FROM AUTHOR]

Copyright of Jornal Brasileiro de Patologia e Medicina Laboratorial is the property of Sociedade Brasileira de Patologia Clinica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Phacomatosis pigmentokeratotica (PPK) is characterized by the co-existence of epidermal nevi and large segmental speckled lentiginous nevi of the papulosa type. PPK, previously explained as 'twin spot' mosaicism due to the postzygotic crossing-over of two homozygous recessive mutations, has recently been shown to derive from one postzygotic activating RAS mutation. Epidermal nevi, including those in PPK, are known to give rise to neoplasms such as trichoblastoma and basal cell carcinoma. Within speckled lentiginous nevi, Spitz nevi and melanoma have been well documented. We report a case of PPK with a combined melanocytic and adnexal neoplasm presenting where the nevi conjoined. Using next-generation sequencing techniques, we were able to identify the same HRAS G13R mutation within both components of the tumor, and to show the absence of additional mutated modifier genes in a panel of 300 cancer-related genes. Given the genetic findings in this rare tumor-type, we suggest that this case may be used as a model for understanding the development of biphenotypic neoplasia or intratumoral heterogeneity in some cases. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Kunming Medical University / Kunming Yike Daxue Xuebao is the property of Kunming Medical Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Electrical bio-impedance can be used to assess skin cancers and other cutaneous lesions. The aim of this study was to distinguish skin cancer from benign nevi using multifrequency impedance spectra. Electrical impedance spectra of about 100 skin cancers and 511 benign nevi were measured. Impedance of reference skin was measured ipsi-laterally to the lesions. The impedance relation between lesion and reference skin was used to distinguish the cancers from the nevi. It was found that it is possible to separate malignant melanoma from benign nevi with 75% specificity at 100% sensitivity, and to distinguish nonmelanoma skin cancer from benign nevi with 87% specificity at 100% sensitivity. The power of skin cancer detection using electrical impedance is as good as, or better than, conventional visual screening made by general practitioners. [ABSTRACT FROM AUTHOR]

This learning exercise challenges clinicians and dermatopathologists to consider the differential diagnosis of an unevenly colored solitary papule over the upper back of an adolescent female. [ABSTRACT FROM AUTHOR]

Histochemical findings of primary and metastatic amelanotic melanomas were shown by the formaldehyde-induced fluorescence method (Falck and Hillarp). All or some of the amelanotic melanoma cells were discovered to emit green specific fluorescence. Results of the determination of 5-S-cysteinyldopa and DOPA in amelanotic melanoma tissues indicated that the specific fluorescence emitted by these cells is primarily due to the presence of 5-S-cysteinyldopa. The values of 5-S-cysteinyldopa in these tissues were lower than those in melanotic melanoma, but were approximately the same as those in pigmented nevus. When unpigmented tumors were histopathologically revealed to be malignant, amelanotic melanoma could be definitely diagnosed by the fluorescence method of Falck and Hillarp and the biochemical analysis of 5-S-cysteinyldopa in the tissues. [ABSTRACT FROM AUTHOR]

Congenital melanocytic nevus consists of congregations of nevomelanocytes. It is found in approximately 1% of new born infants. Congenital melanocytic nevus needs to be excised before it transforms into a malignant lesion. Many strategies have been attempted for the removal and reconstruction of the nevus. Serial excision enables wound closure to be accomplished with a shorter scar than if the original lesion was elliptically excised in a single stage and reorientation of the scar closer to the relaxed skin lines. The routine utilization of an elliptical serial excision as a standard method of closure often leads to the formation of elongated scars and waste of skin. The "Cogwheel pattern" serial excision is a new technique for reducing the size of the nevus efficiently. Reducing the final scar length, distributing the tension over many directions, and having the chance of decrease in operation numbers are ultimately achieved with the use of the "Cogwheel pattern" serial excision. [ABSTRACT FROM AUTHOR]