Bowenoid keratosis on the shin of an 89 year old female patient. Bowenoid keratosis is a form of solar, or actinic, keratosis. This is a pre-cancerous skin growth caused by sun damage. The damage occurs years before the lesion appears. It is important to remove the lesions as they can develop into skin cancer. They may be removed by scraping, freezing with liquid nitrogen, or surgery. New keratosis often appear at or near the site of a previous keratosis, therefore regular check-ups are needed.