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Benign Melanocytic Lesions
Published in Ashfaq A Marghoob, Ralph Braun, Natalia Jaimes, Atlas of Dermoscopy, 2023
Konstantinos Liopyris, Cristian Navarrete-Dechent, Silvia E. Mancebo, Michael A. Marchetti
Melanocytic nevi are common skin lesions and the primary differential diagnosis of early presentations of cutaneous melanoma. Their accurate recognition is critical for efficient skin cancer detection. Fortunately, the majority of melanocytic nevi can be correctly identified after careful clinical and dermatoscopic inspection as well as integration of patient- and lesion-related factors such as age, anatomic location, skin color, and clinical history. In this chapter, we review the common dermatoscopic patterns of melanocytic nevi, including reticular, globular, homogeneous, starburst, peripheral globules, multicomponent patterns, and their variants. We also discuss banal/common nevi, atypical/dysplastic nevi, growing nevi, and congenital nevi. Finally, we point out dermatoscopic features relevant to less common nevus subtypes, including halo nevi, balloon cell nevi, traumatized nevi, combined nevi, and nevi subjected to ultraviolet irradiation.
Benign Neoplasms
Published in Ayşe Serap Karadağ, Lawrence Charles Parish, Jordan V. Wang, Roxburgh's Common Skin Diseases, 2022
Abdullah Demirbaş, Ömer Faruk Elmas, Necmettin Akdeniz
Management: Two factors are primarily associated with the treatment of congenital melanocytic nevi: their increased risk of progression to melanoma and their cosmetically disfiguring appearance. The decision to remove a congenital nevus is individually tailored and based on melanoma risk, age, anatomy, location, nevus quality, cosmetic outcome, and complication rates. Routine excision of small and medium-sized congenital nevi is not performed due to low risk for melanoma. Baseline photography and annual observation is an acceptable alternative. Giant congenital nevi can be observed closely, or removal can be considered. Apart from surgery, laser treatments can be used as an alternative.
Melanomas
Published in E. George Elias, CRC Handbook of Surgical Oncology, 2020
The congenital melanocytic nevus is a skin lesion that contains nevus cells and is present at birth. They can be divided into three groups: small, i.e., less than 1.5 cm in diameter; medium, 1.5 to 2.0 cm; and large, over 2.0 cm. These congenital nevi occur in about 1 % of newborns, have an irregular surface with different shades of brown with hypertrichosis. The lifetime risk of developing cutaneous melanoma in patients with large congenital melanocytic nevi is about 6 to 20%. The incidence of melanoma in small and medium size congenital nevi is rising, but the magnitude is not well determined.16 Therefore, these lesions can be managed by planned consecutive excisions and skin grafts.
Novel insights into the pathogenesis and treatment of NRAS mutant melanoma
Published in Expert Review of Precision Medicine and Drug Development, 2021
Jeffrey Zhao, Carlos Galvez, Kathryn Eby Beckermann, Douglas B. Johnson, Jeffrey A Sosman
We now have evidence at the genomic resolution of single human melanocytes that support the involvement of NRAS at the most proximal steps of the original Clark model of melanoma formation [53,54]. Melanocytes isolated from normal skin obtained from human cadavers and freshly discarded from surgery carry mutations in NRASQ61 [55]. In studies of the progressive evolution of precursor lesions to cutaneous melanoma using microdissection and DNA sequencing of formalin-fixed paraffin-embedded biopsy specimens, mutations in NRAS are early and intermediate steps that occur in parallel to BRAF prior to later genomic events such as alterations in the TERT promoter [56]. Tertiary genomic alterations including copy number changes subsequently develop and push nevi further along the path of melanoma after awakening melanocytes from states of oncogene-induced senescence [57–59]. There is strong evidence that premalignant melanocytic nevi – including those carrying NRAS mutations – progress to form melanoma though there are also isolated reports of melanomas arising from nevi with discordant mutational profiles [59–61]. Benign and premalignant melanocytic lesions including congenital nevi carry mutations in NRAS but not BRAF, whereas histologically similar acquired nevi harbor BRAFV600E mutations more frequently than alterations in NRAS [62–64].
Telmisartan/hydrochlorothiazide-induced nevus-associated cutaneous melanoma: first report in the medical literature
Published in Expert Review of Clinical Pharmacology, 2021
Georgi Tchernev, James W Patterson
The surgery planned for January was postponed to September due to the problem with COVID-19 and the restrictive measures imposed on hospitalization and surgery of all patients. After clinical and dermatoscopic examination and the resulting suspicion of cutaneous melanoma (Figure 1(a,b)), the patient was hospitalized and treated surgically. The suspected lesion was removed in one session by a deep elliptical excision with 2 cm surgical margins in all directions. The resulting defect was closed by a plastic surgery procedure (Figure 1(c,d)). Histopathological examination revealed a nevus-associated cutaneous melanoma with clear resection margins, a Breslow thickness of 0.6 mm, penetration of tumor cells into the reticular dermis (Clark IV), some desmoplasia, a lymphocytic stromal reaction, and one mitosis per mm2. There were no reports of satellite lesions or vascular or perineural infiltration. There was also an associated compound melanocytic nevus with a diameter of 3 mm. Initial screening failed to reveal evidence for the presence of metastases (pT1aN0M0), and computed tomography of the head and body performed 14 days after surgery showed no evidence of metastatic lesions. The patient was referred for follow-up to the regional oncology dispensary.
Biology of Cancer; From Cellular Cancerogenesis to Supracellular Evolution of Malignant Phenotype
Published in Cancer Investigation, 2018
Malignant melanoma typically occurs in the skin starting from melanocytes, which originate from the neural crest, the progenitor cells migrating to and colonizing the basal layer within the skin (27). In support of this affiliation, congenital melanocytic nevi seems to be associated with both neurological abnormalities and melanoma (28). In turn, malignant melanoma presents some similarities with neuroblastoma, like spontaneous remissions (29). However, biology of melanoma seems to be deviated in great extent towards external developmental lineage of blastocyst/trophoblast. Thus, manifestations like proliferative and invasive capacity, the micro-environment, angiogenesis, or systemic immunosuppression (commonly encountered in malignant melanoma) are characteristic rather for trophoblast/placenta than for embryoblast/neural crest (30).