This is a precancerous growth that appears as a scaly, rough, or crusty spot on sun damaged skin such as the face, scalp, ears, and back of the hands. When left untreated, the growth has the potential to form a squamous cell skin cancer, which is the second most common type of skin cancer. Diagnosis and treatment of precancers are important, as 40% of squamous cell skin cancers begin as precancers. Many different treatment options are effective, including freezing spray (cryotherapy), FDA approved creams, and a newer specialized light therapy called photodynamic therapy (PDT). Avail Dermatology offers all of these treatments.