An epithelioid cell type of amelanotic melanoma of the pinna in a Fischer-344 rat: a case report.
Toxicol Pathol
; 24(2): 258-61, 1996.
Article
em En
| MEDLINE
| ID: mdl-8992617
ABSTRACT
An epithelioid cell type of spontaneous amelanotic melanoma in the pinna of an aged albino Fischer-344 (F-344) rat is described. When the rat was necropsied at 109 wk of age, the pinnal tumor was recognized as a white spherical mass of 4 mm in diameter. Histologically, the tumor was observed in the dermis and composed of large round or polyhedral epithelioid eosinophilic cells that were arranged in various-sized cell nests. Immunohistochemistry demonstrated that the tumor cells were positive for S-100 protein and vimentin but negative for keratin and a rat macrophage antigen. Ultrastructurally, a few single membrane-bound premelanosomes that were accompanied by many primary lysosome-like bodies containing very fine granules were present in the cytoplasm of the tumor cells. This study has disclosed that, in addition to spindle cell variants of amelanotic melanomas, an epithelioid cell type of amelanotic melanoma may occur spontaneously in the skin of F-344 rats.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Neoplasias Cutâneas
/
Melanoma Amelanótico
/
Orelha Externa
Limite:
Animals
Idioma:
En
Revista:
Toxicol Pathol
Ano de publicação:
1996
Tipo de documento:
Article