S-100 protein-negative malignant melanoma: fact or fiction? A light-microscopic and immunohistochemical study.
Am J Dermatopathol
; 16(3): 233-40, 1994 Jun.
Article
em En
| MEDLINE
| ID: mdl-7943629
ABSTRACT
S-100 protein is considered a characteristic immunohistochemical marker for all nevomelanocytic lesions, in which it is expected to be present consistently. We reviewed 17 cases of malignant melanomas that previously tested negative for S-100 protein. They were reevaluated by light microscopy, a broad panel of immunohistochemical reagents including monoclonal and polyclonal antibodies to S-100 protein, and electron microscopy. On reexamination, five of the 17 cases were reclassified as non-melanoma tumors, and eight of the 17 cases were found to be positive for S-100 protein (six with monoclonal and eight with polyclonal antibodies) and HMB-45 antigen, consistent with melanoma. The remaining four cases repeatedly tested negative for S-100 protein despite various antigen enhancement methods, but they were positive for HMB-45 antigen and contained premelanosomes or melanosome-like structures by electron microscopy. Two of these repeatedly S-100 negative melanomas were acrally located; although the numbers are small, a possible relationship to a specific anatomic location cannot be excluded. These findings suggest that in a small subset of melanomas S-100 protein is either not fully expressed or is below the level that can be detected by routine immunohistochemistry. We also conclude that in the majority of the initially S-100-negative cases of melanomas, the misdiagnosis may occur due to the use of an incomplete immunohistochemical panel, technical reasons, or the inherent variability of tissue expression of S-100 protein.
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Coleções:
01-internacional
Temas:
Geral
/
Tipos_de_cancer
/
Pele
Base de dados:
MEDLINE
Assunto principal:
Neoplasias Cutâneas
/
Proteínas S100
/
Melanoma
Tipo de estudo:
Diagnostic_studies
Limite:
Humans
Idioma:
En
Revista:
Am J Dermatopathol
Ano de publicação:
1994
Tipo de documento:
Article