Linked article: This article is commented on by M. Scalvenzi et al., pp. e146–e147 in this issue. To view this article visit https://doi.org/10.1111/jdv.15469.

The broad universe of "melanocytic nevi" includes a variety of different subtypes, which can be classified either due to their morphology, epidemiology, genetic alterations or risk for developing melanoma. Regarding morphology, on the one hand macroscopic/clinical and on the other hand histopathological appearance were used to subdivide in the past, often resulting in confusion and poor interobserver agreement, while nowadays dermoscopy presents the clinician's precious bridge between naked-eye examination and histopathological diagnostics, allowing prediction of the lesions' histopathology, follow up and monitoring over time without need of excision. The non-invasive dermoscopic examination relies on the assessment of colors, patterns and the distribution of both within a cutaneous lesion. Until today, the correspondence of certain dermoscopic colors and patterns to certain histopathological correlates has been reported for a huge amount of different cutaneous lesions. Moreover, the correspondence of certain dermoscopic features to certain body sites, age groups and pigmentary traits, but also to specific genetic alterations in lesions, has been broadly investigated. Dermoscopy has led us to a new understanding of melanocytic nevi's biology and evolution and, last but not least, to a new classification system, which we want to present herein.

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Desmoid fibromatosis is a benign fibroblastic neoplasm with high recurrence rates predominantly observed in pediatric and adolescent patients. The use of wide resection margins has been discussed controversially in literature. In addition, data on non-surgical treatment is limited as phase III studies are still missing. Nineteen patients under the age of 18 years were identified. Tumor location, surgical treatment for primary or recurrent tumors, resection margins, medical neo-/adjuvant treatment, time to recurrence as well as immunohistochemical markers (estrogen receptor, ER α and β, progesterone and androgen receptors, somatostatin, Ki-67, c-kit, platelet-derived growth factor receptors, PDGFRs, α and β, β-catenin) were evaluated. The mean age at diagnosis was 6.6 years, with a mean follow-up of 114 months. Recurrences were detected in four out of nineteen patients. Surprisingly, the recurrence rate was not influenced by type of resection used (R0, R1/2). All samples were tested negative for ER α, somatostatin, and progesterone receptor. In contrast, a majority of tumors showed positive results for PDGFR α and β and β-catenin. No correlation between positive immunohistochemical markers and tumor recurrences was detectable. In conclusion, recurrence rates are not depending on resection type and immunohistochemical markers seem to behave differently in children and adolescents in contrast to adult patients.

Today dermoscopy is standard-of-care in the diagnosis and management of patients with benign and malignant skin tumors because it increases the diagnostic accuracy of skin lesions compared to the naked-eye examination up to 25%. Despite its role in the routine dermato-oncology, it increasingly gained interest as a bridge connecting clinical with basic molecular research in dermato-oncology. Here, we correlate dermoscopy patterns of nevi and melanomas with high and low susceptibility genes and somatic mutations, provide an overview on the clinical and dermoscopic patterns of cutaneous melanoma subtypes, and highlight the role of dermoscopy in the diagnosis of skin eruptions during systemic treatments of advanced melanoma including targeted therapies and immunotherapies.