Imiquimod 5% cream: a new treatment for Bowen's disease.

Bowen's disease (BD) is a squamous cell carcinoma in situ. Recent studies suggest that human papilloma virus plays an important role in the development of BD. We investigated whether imiquimod 5%, a topical immune response modifier, is an effective treatment for BD in five immunocompetent patients. The lesions were one genital and four extragenital. The frequency of application varied from three times weekly up to twice daily, and treatment duration ranged from 8-24 weeks. Four patients achieved clinical and histological cure. The patient with the genital lesion gained an important reduction in size and infiltration, which enabled surgical removal of the remaining lesion with good functional and cosmetic result. Our results suggest that topical imiquimod 5% is an effective treatment for BD through its viral and antitumor effects.