21. Carcinoma in Situ
The most severe cases of dysplasia are sometimes referred to as "carcinoma in situ." In Latin, the term "in situ" means "in place," so carcinoma in situ refers to an uncontrolled growth of cells that remains in the original location. However, carcinoma in situ may develop into an invasive, metastatic malignancy and, therefore, is usually removed surgically, if possible.