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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.
Melanoma-associated emergencies
Published in Biju Vasudevan, Rajesh Verma, Dermatological Emergencies, 2019
Vidya Kharkar, M. R. L. Sujata
The risk of malignant transformation in congenital melanocytic nevi (CMN) depends on the size of the lesion. For large CMN (largest diameter >20 cm), lifetime risk of melanoma transformation is between 5% and 15% [10,11]. Malignant transformation most often occurs during childhood [10,12,13]. The risk of transformation of small CMN is between 2.6% and 4.9% in CMN <4.5 cm in diameter [14].
Skin and soft tissue
Published in Tor Wo Chiu, Stone’s Plastic Surgery Facts, 2018
Congenital melanocytic nevi – When to worry and how to treat. (Price HN, Clin Dermatol, 2010)Risk of melanoma in small- and medium-size CMN is low and is nearly zero before puberty.Risk of melanoma in giant CMN is ~5%, with half in the first few years of life.Melanoma and neurocutaneous melanosis (NCM) are most likely when size or predicted size >40 cm, numerous satellites (>20) and truncal/midline lesions.NCM is found in ~1/3 of GCMN, with 1/3 of these being symptomatic, e.g. raised ICP, hydrocephalus, development delay or space-occupying lesion; most die within 2–3 years of the development of symptomatic disease.The management of asymptomatic NCM remains controversial, and the role of MRI screening is also debatable, except perhaps before major surgery.Some suggest a baseline MRI at the age of 4–6 months before normal brain myelination obscures small lesions.
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).
Genomic analysis of adult case of ocular surface giant congenital melanocytic nevus and associated clinicopathological findings
Published in Ophthalmic Genetics, 2020
Lindsay A McGrath, Jane M Palmer, Andrew Stark, William Glasson, Sunil K Warrier, Kevin Whitehead, Hayley Hamilton, Kelly Brooks, Peter A Johansson, Nicholas K Hayward
On presentation, best-corrected visual acuity was 6/5 bilaterally. Slit-lamp examination revealed an unstable tear film with punctate corneal erosions. There was gross melanosis of the left upper and lower lids, medial caruncle, canthus, plica, and conjunctiva with medial involvement more marked than lateral involvement (Figure 1a-d). The medial canthus area appeared somewhat suspicious for malignant transformation. Cystic features typical of nevi were also present throughout the conjunctival component of the lesion. Together these findings upheld the provisional diagnosis of a medium congenital melanocytic nevus of the left periocular region with associated GCN.