Squamous cell carcinoma is a relatively common type of skin malignancy, and its development is related to the following factors: 1, physical and chemical factors, such as exposure to some coal tar or arsenic-containing agents; 2, caused by radioactive dermatitis or repeated exposure to rays; 3, viral infections, such as HPV infections, which may cause huge condyloma acuminatum on the vulva or perianal area, and may also lead to squamous cell carcinoma; 4, the recurrence of chronic inflammatory diseases of the skin, such as chronic ulcers, burns, and discoid lupus erythematosus, which may be followed by squamous cell carcinoma; and 5, the sunburned keratosis subjected to long-term stimulation or ultraviolet irradiation, etc, which may also evolve into squamous cell carcinoma of the skin.