Melanoma desmoplástico / Desmoplastic melanoma

Descrito pela primeira vez em 1971 por Conley et al., o melanoma desmoplásico (MD) representa menos de 4% dos melanomas cutâneos. Trata-se de variante distinta e incomum,que se caracteriza por tumor fibroso de células fusiformes liberadoras de colágeno em matriz fibrosa. Seu diagnóstico é propenso a erro, principalmente por sua semelhança com outras neoplasias fibrosas. Em cerca de 600 casos descritos na literatura, observou-se apresentação clínica não pigmentada, profunda e de aspecto fibroso, associada à lesão precursora. Seu reconhecimento é de grande importância devido ao comportamento de caráter recidivante e à consequente necessidade de abordagem cirúrgica distinta.

First described in 1971 by Conley and colleagues, desmoplastic melanomas represent less than 4% of cutaneous melanomas. It is a distinctive and uncommon variant characterized by a spindle cell fibrous tumor of collagen forming cells, isolated by dense fibrous matrix.Desmoplastic melanomas are frequently misdiagnosed, mainly due to their similarity to other fibrous neoplasms. A review of about 600 reported cases unexpectedly revealed the pigmented clinical presentation of a deep and fibrous nodule that is classically associated with a precursor lesion. The ability to recognise this lesion?s characteristics is very important, due to its recurrent behaviour and subsequent need for a specialized surgical approach.

A Case of Dermal Melanocyte Hamartoma / 대한피부과학회지

Dermal melanocytosis is characterized by the presence of ectopic melanocytes in the dermis. Dermal melanocytosis assumes several morphologic forms, including the Mongolian spot, the blue nevus, the nevus of Ota, the nevus of Ito and dermal melanocytic hamartoma. Differential diagnostic features of these dermal melanocytic lesions depend on onset, course, distribution, histologic features, uniformity of pigmentation, etc. In our case, an 18-year-old girl had asymptomatic 5x3cm sized ill-defined bluish patch on left forearm since birth. Histologic examinations revealed marked increased infiltrate of pigment cells mainly in the upper dermis in Hematoxylin & eosin stain . Fontana-Masson stain and Gp 100 stain revealed marked infiltrate of melanin-containing cells in upper dermis. We report a rare case of dermal melanocyte hamartoma.

A Pre-embedding Technique of Nanogold-Silver Staining for Immunocytochemical Localization of Gp100 in Cultured Melanocytes / 대한해부학회지

Nanogold-silver staining is a pre-embedding immunocytochemical technique, making it possible to label antigens with particulate markers at the electron microscopic level. This technique is based on the advancement of gold technology and on the development of silver staining or enhancement. In the present study, the method of Nanogoldsilver staining that includes the use of high concentration of glutaraldehyde and gold toning as well, was used to localize gp100 or a membrane bound antigen in melanosome of the cultured melanocytes. With the HMB45 antibody against gp100, biotinylated secondary antibody and streptavidin-nanogold followed by silver enhancement and gold toning led to highly specific labeling of gold particle over the melanosome compartments. The specificity of labelings obtained with this protocol was confirmed by the control experiment. Omission of the primary antibody led to very low background of labeling. The specific signal that appeared as a collection of gold particles was localized mainly to the peripheral part of melanosome. This finding provides the more detailed nature of gp100 localization in melanosome, which has not yet been shown by the previous immunocytochemical study such as the post-embedding immunoelectron microscopy.