[Immunohistological demonstration of the intermediate filaments in a laryngeal carcinosarcoma: considerations on its...

A carcinosarcoma of the larynx was analysed by means of a light microscope and by immunohistological staining technique using antibodies against various intermediate filament proteins. Whereas tumour areas of an epithelial character reacted with antibodies against keratin, the spindle cells demonstrated a positive immunofluorescence with vimentin antibodies. Inside some tumour cells a coexpression of keratin and vimentin (intermediate filaments of mesenchymal cells) could be demonstrated. It is likely that these double stained cells represent the primitive stem cell of the carcinosarcoma, differentiating during further development either into epithelial or mesenchymal tumour cells.