Esophageal carcinoma with prominent spindle cells.

Eight cases of esophageal carcinoma with prominent spindle cells (carcinosarcoma or pseudosarcoma) were studied using the avidin-biotin immunoperoxidase method and monoclonal antibodies to various keratins and vimentin. In all eight cases positive immunoreactivity for keratin was found in carcinomatous areas and for vimentin, in the spindle cells. It is interesting that five cases demonstrated focal immunoreactivity to keratin in the spindle cell component. Trace positivity to vimentin was seen in the carcinomatous areas in one case. These findings are consistent with the hypothesis that esophageal carcinoma with prominent spindle cells is of epithelial origin and may represent a morphologic variant of squamous cell carcinoma.