Verrucous carcinoma is a relatively uncommon, locally aggressive, clinically exophytic, low-grade, slow-growing, well-differentiated squamous cell carcinoma with minimal metastatic potential.
Verrucous carcinoma may involve the oral cavity, larynx, anogenital region, plantar surface of the foot, and, less commonly, other cutaneous sites. See the image below.
In 1948, Ackerman first described verrucous carcinoma in the oral cavity as a low-grade tumor that generally is considered a clinicopathologic variant of squamous cell carcinoma.  Aird et al first described cutaneous verrucous carcinoma (carcinoma cuniculatum) in 1954, and it was named as such because of its characteristic cryptlike spaces on histology. 
The pathogenesis of verrucous carcinoma is not yet fully elucidated.  Leading theories include human papillomavirus (HPV) infection (oral cavity, anogenital region, plantar foot, and a small subset of cutaneous verrucous carcinoma),  chemical carcinogenesis induced by smoking and chewing tobacco,  alcohol consumption and betel nut chewing (oral lesions), and chronic inflammation. Schistosomiasis is associated with verrucous carcinoma of the bladder. 
The incidence of verrucous carcinoma in the United States and worldwide is unknown. 
Verrucous carcinoma is reported predominantly in whites.
Verrucous carcinoma primarily affects men.
Overall, patients with verrucous carcinoma have a favorable prognosis, although the course of verrucous carcinoma lesions is characterized by slow, continuous, local growth. Morbidity results from local skin and soft-tissue destruction and, occasionally, from perineural, muscle, and even bone invasion. The development of distant metastases is rare. Verrucous carcinoma mortality usually is due to local invasion rather than metastatic spread.
In most cases of verrucous carcinomas, regardless of the variant, the clinical outcome is rarely an aggressive course. Local verrucous carcinoma recurrence following definitive treatment is not uncommon. Regarding oral verrucous carcinoma, the reported recurrence rate ranges from 6-40%. If metastasis does occur, it is mainly at the regional lymph nodes.  There have been reports of metastases in distant sites, but this is considered rare. In long-standing lesions, occasional destruction of adjustment structures such as cartilage, tendons, and bones can occur. Patients with oral verrucous carcinoma may be at an increased risk of a second primary oral squamous cell carcinoma, which carries a poor prognosis.
Advise patients about the importance of receiving effective treatment for areas of chronic skin inflammation or trauma (eg, leg or decubitus ulcers) to prevent these problems from developing malignancies within them. Improved oral, genital, and perianal hygiene may help to prevent inflammatory conditions that predispose patients to verrucous carcinoma. Cessation of chewing tobacco use may help to prevent oral verrucous carcinoma.