Congenital melanocytic nevi: Where are we now? Part I. Clinical presentation, epidemiology, pathogenesis, histology, malignant transformation, and neurocutaneous melanosis
ABSTRACT Congenital melanocytic nevi (CMN) are present at birth or arise during the first few weeks of life. They are quite common, may have a heritable component, and can present with marked differences in size, shape, color, and location. Histologic and dermatoscopic findings may help suggest the diagnosis, but they are not entirely specific. CMN are categorized based on size, and larger lesions can have a significant psychosocial impact and other complications. They are associated with a variety of dermatologic lesions, ranging from benign to malignant. The risk of malignant transformation varies, with larger CMN carrying a significantly higher risk of malignant melanoma (MM), although with an absolute risk that is lower than is commonly believed. They may also be associated with neuromelanosis, which may be of greater concern than cutaneous MM. The information presented herein aims to help dermatologists determine when it is prudent to obtain a biopsy specimen or excise these lesions, to obtain radiographic imaging, and to involve other specialists (eg, psychiatrists and neurologists) in the patient's care.
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ABSTRACT: Although rare, malignant melanoma may occur in children. Childhood melanomas account for only 0.3-3% of all melanomas. In particular the presence of congenital melanocytic nevi is associated with an increased risk of development of melanoma. We herein report a case of malignant melanoma that developed on a giant congenital melanocytic nevus and made a metastasis to the subcutaneous tissue of neck in a two-year-old girl. The patient was hospitalized for differential diagnosis and treatment of cervical mass with a suspicion of hematological malignancy, because the malignant transformation of congenital nevus was not noticed before. In this case, we found out a nonpigmented malignant tumor of pleomorphic cells after the microscopic examination of subcutaneous lesion. Nonpigmented metastatic melanoma was diagnosed by several immunohistochemical and flow cytometric studies. She was offered palliative chemotherapy; however, her parents did not accept treatment. The patient died within 9 months of diagnosis. We emphasized here that the possibility of malignant melanoma in the differential diagnosis of childhood tumors should be kept in mind.01/2015; 2015:298273. DOI:10.1155/2015/298273
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ABSTRACT: Tyr::NRas(Q61K) ; Cdkn2a(-/-) mice were generated to spontaneously develop metastasizing cutaneous melanoma. Despite wide popularity in the melanoma community, histopathological descriptions of melanocytic lesions in this model remain scarce. To fully characterize the variety of melanocytic lesions in this model, thorough necropsies were performed followed by histopathological examination. We show that melanoma development in Tyr::NRas(Q61K) ; Cdkn2a(-/-) transgenic mice is a multistep process that involves at least four types of cutaneous melanocytic lesions with distinctive morphological features. For each type, detailed histopathological description, illustrations and comparison with human melanocytic lesions are given. Primary melanocytic lesions, including melanoma, were also identified in non-cutaneous sites, mainly the brain and the eyes. Interestingly, some features in lymph nodes lesions suggest that primary melanocytic lesions may develop in addition to metastases. The classification herein proposed should set up the basis for a common language in the melanoma community working with Tyr::NRas(Q61K) ; Cdkn2a(-/-) transgenic mice. This article is protected by copyright. All rights reserved.Pigment Cell & Melanoma Research 05/2013; 26(5). DOI:10.1111/pcmr.12115 · 5.64 Impact Factor
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ABSTRACT: The elliptical excision is the standard method of removing benign skin lesions, such as congenital melanocytic nevi. This technique allows for primary closure, with little to no dog-ear deformity, but may sacrifice normal tissue adjacent to the lesion, resulting in scars which are unnecessarily long. This study was designed to compare the predicted results of elliptical excision with those resulting from our excision technique. Eighty-two patients with congenital melanocytic nevus on the face were prospectively studied. Each lesion was examined and an optimal ellipse was designed and marked on the skin. After an incision on one side of the nevus margin, subcutaneous undermining was performed in the appropriate direction. The skin flap was pulled up and approximated along several vectors to minimize the occurrence of dog-ear deformity. Overall, the final wound length was 21.1% shorter than that achieved by elliptical excision. Only 8.5% of the patients required dog-ear repair. There was no significant distortion of critical facial structures. All of the scars were deemed aesthetically acceptable based on their Patient and Observer Scar Assessment Scale scores. When compared to elliptical excision, our technique appears to minimize dogear deformity and decrease the final wound length. This technique should be considered an alternative method for excision of facial nevi.09/2013; 40(5):570-574. DOI:10.5999/aps.2013.40.5.570