Polypoid spindle-cell carcinoma (pleomorphic carcinoma). Report of a case occurring on tongue and review of the literature.

A case of spindle-cell carcinoma (pleomorphic carcinoma), a rare polypoid tumor of the tongue, is reported. The characteristic clinical, gross, and microscopic features of this peculiar lesion and its common sites of location are presented. Origin and pathogenesis of the sarcoma-like elements of the lesion are discussed and the literature on the subject is reviewed. Sites of apparent transition between the spindle cell elements of the tumor and the overlying epithelium were observed in light microscopic sections, and the electron micrographs of the spindle-cell portion of the lesion demonstrated the presence of tonofilaments and desmosomes in many tumor cells. These findings support the concept that this group of lesions are pleomorphic variants of squamous-cell carcinoma with predominantly spindle-cell pattern. Current evidence in the literature also suggests that metaplastic transformation of the tumor cells into mesenchymal elements may take place in some of these lesions, and that "metaplastic carcinoma" may probably be a more proper designation for them.