A 70-year-old male patient presented with an extensive verrucous, hyperkeratotic tumor on the central aspect of his lower lip (Fig. 1A). The tumor had been growing for 1 month. The patient was a smoker and a social alcohol drinker. However, his history of trauma to the lesion was unremarkable and he had no past medical history or family history of similar lesions or other skin diseases. Physical examination revealed an exophytic verrucous yellowish-to-whitish tumor measuring approximately 4 cm in diameter. The patient complained of mild tenderness on the lesion and the tumor was firm upon palpation. No lymphadenopathy was detected on the neck or sublingual area.

Microscopic examination of a punch biopsy specimen revealed an endophytic epidermal proliferation with bulbous and blunted projections composed of large well-differentiated squamous epithelial cells extending into the reticular dermis (Fig. 2A). Cellular pleomorphism was minimal and mitotic activity was confined to the basal layer (Fig. 2B). Based on these findings, the patient was diagnosed with verrucous carcinoma. Carbon dioxide laser treatment was then performed following tumescent local anesthesia using lidocaine 0.2%.

After 10 days, the wound was completely epithelialized. At this point, topical treatment with imiquimod was started, with application of cream to the washed and dried tumor surface and then washed off 12 hours after application 3 times per week. After 4 weeks of treatment, the verrucous plaques had decreased in size; however, formation of mild erythema and crust with oozing was observed on the tumor and the patient complained of local pain. Therefore, application of imiquimod was then stopped and the patient received oral administration of analgesics and topical application of antibiotics to the tumor. Over a 4-week period of treatment with analgesics and topical antibiotics, local pain, erythema, and crust slowly disappeared. At this point, administration of imiquimod was started again, with application of treatment 3 times per week over a period of 4 weeks. Treatment was well tolerated by the patient and no unwanted side effects occurred. After 3 months of treatment, the tumor was clinically resolved (Fig. 1B).

A 75-year-old male developed painful hyperkeratotic plaques on the right aspect of his lower lip, which had persisted for more than 6 months (Fig. 3A). Prior to his visit to our hospital, the patient had been diagnosed with verrucous carcinoma based on the results of a histologic examination conducted at another hospital. Because the lesions progressed in size after the biopsy, he visited our hospital without treatment. The patient was a heavy smoker, but had no previous history of trauma or exposure to radiation.

Physical examination revealed verrucous plaques with fissuring on the right aspect of the lower lip. Microscopically, the specimen showed marked parakeratosis, neoplastic proliferation, and downward invasion of epidermal keratinocytes with a blunt border and a pushed-down, bulldozing appearance. Inflammatory cell infiltrates surrounding the tumor were also observed (Fig. 4).

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).