Immunohistochemical study of malignant melanoma

ABSTRACT

Formalin fixed paraffin embedded sections of 15 cases of malignant melanoma of the skin were studied immunohistochemically for the presence of vimentin, cytokeratin and neurofilament proteins. The original diagnosis of malignant melanoma was confirmed in each case based on a histologic examination. It was found that vimentin was present in the cytoplasm of the majority of all cases. However, cytokeratin immunostaining was found in three out of 15 melanoma cases. In contrast, two melanoma cases contained neurofilament positive tumor cells. It was concluded that melanomas containing exclusively vimentin intermediate filaments prove to be useful in the differential diagnosis of melanomas from other tumor types. Also, melanoma cells are considered as interconverted cells as they display both mesenchymal and epithelial phenotypes