Lentigo maligno microinvasivo
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Data
2016-07-29
Autores
Camboim, Denise Cruz [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O uso da imuno-histoquímica pode aumentar a acurácia na detecção de melanócitos neoplásicos na derme. Com o objetivo de pesquisar microinvasão, cento e nove casos previamente diagnosticados como lentigo maligno (LM) foram resgatados dos arquivos do Departamento de Patologia da Faculdade de Medicina de Botucatu, da Universidade Estadual Paulista (FMB/UNESP) no período de 01/01/2002 a 01/01/2014. As lâminas histológicas de todos os casos foram revisadas pelos autores para confirmação do diagnóstico e seleção do bloco mais representativo para realização de estudo imuno-histoquímico com Melan-A e MITF. Em 25 casos (22,9%) foi observada invasão focal da derme por melanócitos neoplásicos claramente imunomarcados pelo Melan-A. Nos locais onde se evidenciou invasão foi realizada a medida da espessura de Breslow que variou de 0,1 a 0,45 mm. A coloração imuno-histoquímica com MITF evidenciou positividade focal na derme, porém a identificação das células coradas não permitiu a mesma segurança da coloração pelo Melan-A. Todas as lâminas de imuno-histoquímica foram contracoradas pelo Giemsa para diferenciar positividade para o anticorpo testado e melanina. O presente estudo permitiu identificar microinvasão dérmica em 22,9% dos casos de lentigo maligno, mostrando a possibilidade de estadiamento e tratamento inadequado quando utilizada a técnica de rotina. Os achados são um alerta para os patologistas e clínicos, especialmente em lesões de grandes dimensões e associadas com infiltrado linfocitário que obscurece os limites da mesma.
The use of immunohistochemistry can enhance the accuracy in detecting neoplastic melanocytes in the dermis. In order to search for microinvasion, one hundred and nine cases previously diagnosed as lentigo maligna (LM) were retrieved from the archives of the Department of Pathology, Faculty of Medicine of Botucatu, Universidade Estadual Paulista (FMB / UNESP) in the period of 01/01 / 2002 to 01/01/2014. The histological slides of all cases were reviewed by the authors to confirm the diagnosis and selection of the most representative block for performing immunohistochemical study with Melan-A, and MITF. In 25 cases (22.9%) was observed focal dermal invasion by neoplastic melanocytes clearly immunostained for Melan-A. In these cases the Breslow thickness ranged between 0.1 and 0.45mm. Immunohistochemical staining showed MITF focal positivity in the dermis, but did not allow the same certainty of Melan-A staining. In order to distinguish melanin in macrophage cytoplasm from brown-staining melanocytes, the slides were counterstained by Giemsa. This study identified dermal microinvasion in 22.9% cases of lentigo maligna, showing the possibility of inadequate staging and treatment when using the routine technique. The findings are a warning for pathologists and clinicians, especially in large lesions and associated with lymphocytic infiltrate that obscures their limits.
The use of immunohistochemistry can enhance the accuracy in detecting neoplastic melanocytes in the dermis. In order to search for microinvasion, one hundred and nine cases previously diagnosed as lentigo maligna (LM) were retrieved from the archives of the Department of Pathology, Faculty of Medicine of Botucatu, Universidade Estadual Paulista (FMB / UNESP) in the period of 01/01 / 2002 to 01/01/2014. The histological slides of all cases were reviewed by the authors to confirm the diagnosis and selection of the most representative block for performing immunohistochemical study with Melan-A, and MITF. In 25 cases (22.9%) was observed focal dermal invasion by neoplastic melanocytes clearly immunostained for Melan-A. In these cases the Breslow thickness ranged between 0.1 and 0.45mm. Immunohistochemical staining showed MITF focal positivity in the dermis, but did not allow the same certainty of Melan-A staining. In order to distinguish melanin in macrophage cytoplasm from brown-staining melanocytes, the slides were counterstained by Giemsa. This study identified dermal microinvasion in 22.9% cases of lentigo maligna, showing the possibility of inadequate staging and treatment when using the routine technique. The findings are a warning for pathologists and clinicians, especially in large lesions and associated with lymphocytic infiltrate that obscures their limits.
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Palavras-chave
Melan-A, MITF, Lentigo maligno, Microinvasão, Imuno-histoquímica