What is squamous cell carcinoma in situ?
Early forms of squamous cell carcinoma are classified as in situ, which means “in place” in Latin. Squamous cell carcinoma is one of the most common types of skin cancer. It forms when squamous cells begin to grow uncontrollably in the outer part of the epidermis, which is the top layer of our skin. In most instances, it is caused by repeated exposure to UV rays over time.