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A variant of well-differentiated epidermoid carcinoma that is most common in the oral cavity, but also occurs in the larynx, nasal cavity, esophagus, penis, anorectal region, vulva, vagina, uterine cervix, and skin, especially on the sole of the foot. Most intraoral cases occur in elderly male abusers of smokeless tobacco. The treatment is surgical resection. Radiotherapy is not indicated, as up to 30% treated with radiation become highly aggressive within six months. (Segen, Dictionary of Modern Medicine, 1992)