[Skin cancer and precancerosis].

Both basal cell carcinoma (bcc) and squamous cell carcinoma (SCC) are very common in Japan, followed by Bowen's disease, actinic keratosis and Paget's disease. Bcc has a strong tendency to invade deeply, although distant metastasis is extremely rare. Differentiation from malignant melanoma is sometimes necessary in the case of pigmented bcc. As for scc, the most common predisposing factors in Japan are various kinds of scars. Recently, however, incidence of actinic keratosis-scc is has been increasing. Verrucous carcinoma is a variant with low-grade malignancy, and is considered to be induced by human papilloma virus. In genital Paget's-and Bowen's disease dermal invasion is seen in about 20% of cases various types of internal malignancy occurring in about 15%. Although surgery is the first choice of treatment for skin cancer and precancerous disease, peplomycin is very effective for scc. The latter has generally been used mainly in the preoperative stage.