HB Kwon, et al Fig. 4. A biopsy specimen revealed marked parakeratosis, neo- plastic proliferation, and downward invasion of epidermal kera- tinocytes with a blunt border and a pushed-down, bulldozing appearance (H&E, ×20). Cryotherapy was performed. Specifically, a cotton stick containing liquid nitrogen was applied to the skin lesion for 2 seconds three times with an interval of five seconds in between each application. Within a few hours of treatment, hyperemia and swelling were obvious and edema and hyperemia increased slowly over a period of 48 hours. The treated mucosa then became covered with a yellowish slough that separated after 7 days. The treated lesion healed completely within 14 days, at which point topical treatment with imiquimod was started, with application of cream 3 times per week. After 3 weeks of treatment, the verrucous plaques almost completely disappeared; however, formation of mild erythema and crust was observed on the tumor, without pain. Topical treatment with imiquimod was continued, with no additional side effects, and, after 7 weeks of treatment, this area was clinically resolved (Fig. 3B). S70 Ann Dermatol Fig. 3. (A) Verrucous plaques with fissuring on the right aspect of the lower lip. (B) After treatment, all skin lesions disappeared. DISCUSSION The natural history of verrucous carcinoma of the skin is marked by slow growth of a well-circumscribed tumor, which often shows a papillomatous surface. The tumor is typically located on the sole of the foot or elsewhere on the lower extremities; however, other locations, including the buttocks or the palm of the hand, have been reported4. In 1981, Diaz-Pérez et al.5 first reported lip verrucous carcinoma similar to the cases described. In addition, Krutchkoff et al.6 reported that verrucous carcinoma on the lip constituted only 2.8% of all oral neoplasms. Although the cause of verrucous carcinoma is still unclear, it has been reported to have an association with earlier injuries and scars, as well as with chronic inflammation3,7. Chewing tobacco, betel nuts, and dipped snuffs are also associated with development of verrucous carcinoma of the lip2. Although the role of human papillomaviruses in development of verrucous carcinoma of the skin is still unclear, DNA of human papillomaviruses has been identified in such carcinomas8,9. However, in a clinicopathologic study, Kao et al.4 were unable to demonstrate the presence of virus particles in specimens. Treatment modalities for verrucous carcinoma include surgical excision, chemotherapy, cryosurgery, intralesional or iontophoretic methods, systemic retinoid therapy, and radiotherapy. Surgical excision is the treatment of choice for verrucous carcinoma. However, incomplete resection can result in accelerated tumor growth; therefore, care must be taken to fully remove all parts of the tumor. In addition, when surgical excision is considered, the size of the defect is often the most important factor because it is usually a strong indicator of the optimal method of reconstruction10. A defect of approximately 30% of the upper or lower lip can be reconstructed by the primary closure due to the great elasticity of the lip11. In our case, total excision was not performed because the tumor encompassed greater than 30% of the lower lip. If a wide excision had been performed in these cases, the defect would have required more complicated reconstructive