Recent trend in the incidence of premalignant and malignant skin lesions in Korea between 1991 and 2006.

We evaluated the recent trend in the incidence of premalignant and malignant skin lesions between 1991 and 2006. Among 571,057 newly registered dermatology out-patients from our 8 affiliated university hospitals, 2,598 were diagnosed with a premalignant (899, 0.16%) or malignant skin lesions (1,699, 0.30%). Of 899 premalignant cases, 71.2% were actinic keratosis (AK), and 24.6% were Bowen's disease. Of 1,699 malignant cases, 46.2% were basal cell carcinoma, followed by squamous cell carcinoma (19.1%) and melanoma (7.1%). This 16-yr survey was divided equally into two time periods to compare the incidence of premalignant and malignant skin lesions at different time settings. Between 1991 and 1998, the incidence of cutaneous premalignancy was 0.10% which doubled during 1999-2006. For cutaneous malignancy, the incidence was 0.25% during 1991-1998 and 0.34% in 1999-2006. Incidence of AK among the new outpatients was 0.07% in 1991-1998 which staggered up to 0.15% in 1999-2006. These findings show an increase of both premalignant and malignant skin lesions, AK in particular in the dermatology outpatient-based incidence.