Spindle cell carcinoma (SpCC) is a biphasic tumor consisting of a squamous cell carcinoma component and a sarcomatoid component of spindle cells. Without immunohistochemical or ultrastructural study, it is difficult to differentiate the sarcomatoid component of SpCC from sarcoma.
We describe a case of spindle cell carcinoma arising as a polypoid mass in the tongue of a 74-year-old woman. The mass was successfully differentially diagnosed on immunohistochemical analysis. Pathological analysis of the tumor revealed three components of squamous cells, histiocyte-like cells, and spindle cells. Immunohistochemical characterization of tumor cells was done with antibodies to keratin, vimentin, smooth muscle actin, desmin, and 5-100 protein to differentiate SpCC from melanoma and leiomyosarcoma. The histiocyte-like cells and spindle cells were positive for keratin and vimentin, and negative for smooth muscle actin, desmin, and 5-100 protein. Given these findings, we diagnosed SpCC. In the 7 months following surgery, there has been no local recurrence or metastasis.
