Spindle-cell carcinoma of the oral cavity.

Two autopsy cases are presented of spindle-cell carcinoma of the oral cavity, which were transformations from the pre-existing well differentiated squamous cell carcinoma in Case 1 and verrucous carcinoma in Case 2, after large doses of irradiation. In Case 2, the conventional squamous cell carcinoma existed at the time of biopsy. Our case study suggests that the spindle-cell carcinoma may develop from the verrucous carcinoma by dedifferentiation through the intermediate stage of conventional squamous cell carcinoma.