De novo melanoma and melanoma arising from pre-existing nevus: in vivo morphologic differences as evaluated by confocal microscopy.

BACKGROUND: Although in the majority of melanomas there is no evidence of pre-existing melanocytic nevus, it is believed that malignant transformation may sometimes occur within a benign precursor. OBJECTIVES: We sought to describe the morphologic features of de novo melanoma and melanoma arising from nevi by means of in vivo confocal microscopy, and to correlate them with their corresponding histopathologic features. METHODS: A total of 113 consecutive, histopathologically proven melanoma cases, 33 arising from a nevus and 80 occurring de novo, were imaged by confocal microscopy and retrospectively evaluated. Cyto-architectural features preferentially expressed in melanomas arising from nevi and in de novo melanomas were defined. RESULTS: By confocal microscopy, abrupt transition, localized distribution of junctional atypical cells, and the presence of dense dermal nests were the most helpful criteria for categorizing a melanoma as arising from a nevus. Melanomas arising from common and congenital nevi were predominantly composed of roundish, monomorphous cells, whereas melanomas arising either de novo or from dysplastic nevi were characterized by markedly pleomorphic cells. LIMITATIONS: The study is retrospective. CONCLUSION: Confocal microscopy is effective in identifying melanoma even when a nevus is simultaneously present, confirming the clinical usefulness of this methodology. Moreover, distinctive features were observed in de novo melanomas and melanomas arising from nevi, permitting accurate distinction between the two groups. Finally, differences in cell morphology, easily detectable by confocal microscopy, seemed to characterize different melanoma types.

Microscopia confocal reflectante aplicada ao diagnóstico do melanoma cutâneo: [revisão] / Reflectance confocal microscopy in the diagnosis of cutaneous melanoma: [review]

O melanoma cutâneo é um problema de saúde pública a nível mundial. Sua incidência tem aumentado, de forma marcante, nos últimos anos, e o diagnóstico e excisão precoces são essenciais para o bom prognóstico dos pacientes. Neste contexto, a dermatoscopia ganhou grande importância, nas últimas duas décadas, melhorando, de forma significativa, a acurácia do diagnóstico do melanoma, em estágios iniciais. Porém, existem algumas lesões benignas que apresentam dermatoscopia duvidosa, levando à realização de cirurgias desnecessárias. Mais recentemente, a microscopia confocal reflectante vem sendo introduzida como método diagnóstico auxiliar promissor, por ser um exame não-invasivo, realizado in vivo, de forma simples, indolor e de rápida execução. É a única técnica capaz de identificar estruturas celulares e examinar a epiderme e a derme papilar, com resolução semelhante à da histopatologia, com uma sensibilidade de 97,3 por cento, e especificidade de 72,3 por cento para o diagnóstico do melanoma cutâneo. É uma importante ferramenta diagnóstica, visto que não substitui o exame histopatológico realizado no pós-operatório, mas permite a abordagem racional das lesões com dermatoscopia duvidosa, evitando procedimentos cirúrgicos desnecessários.

Skin melanoma is an international public health issue, with a considerable increase in frequency over the past few years. Early diagnosis and excision are essential for good patient prognosis. Over the past two decades dermoscopy has gained significance due to a major improvement in the accuracy of skin melanoma diagnosis in its early stage. However, there are some benign lesions of questionable dermoscopy, which may lead to the performance of unnecessary surgery. Recently, reflectance confocal microscopy has been introduced as a promising supplementary diagnostic method. It is a noninvasive, in vivo, simple, painless and quick exam. It is the only technique capable of identifying cellular structures and to examine the epidermis and papillary dermis with a resolution similar to that of histopathology, with a sensitivity of 97.3 percent and specificity of 72.3 percent in the diagnosis of cutaneous melanoma. This is an important diagnostic tool, because it does not substitute post-surgical histopathological examination and allows for the rational assessment of lesions of questionable dermoscopy, thus avoiding unnecessary surgical procedures.

[Reflectance confocal microscopy in the diagnosis of cutaneous melanoma]. / Microscopia confocal reflectante aplicada ao diagnóstico do melanoma cutâneo.

Skin melanoma is an international public health issue, with a considerable increase in frequency over the past few years. Early diagnosis and excision are essential for good patient prognosis. Over the past two decades dermoscopy has gained significance due to a major improvement in the accuracy of skin melanoma diagnosis in its early stage. However, there are some benign lesions of questionable dermoscopy, which may lead to the performance of unnecessary surgery. Recently, reflectance confocal microscopy has been introduced as a promising supplementary diagnostic method. It is a noninvasive, in vivo, simple, painless and quick exam. It is the only technique capable of identifying cellular structures and to examine the epidermis and papillary dermis with a resolution similar to that of histopathology, with a sensitivity of 97.3% and specificity of 72.3 % in the diagnosis of cutaneous melanoma. This is an important diagnostic tool, because it does not substitute post-surgical histopathological examination and allows for the rational assessment of lesions of questionable dermoscopy, thus avoiding unnecessary surgical procedures.