historically, abnormal changes of cervical epithelial cells were described as mild, moderate, or severe epithelial dysplasia. in 1988 the national cancer institute developed "the bethesda system for reporting cervical/vaginal cytologic diagnoses." this system provides a uniform way to describe abnormal epithelial cells and determine specimen quality, thus providing clear guidance for clinical management. these abnormalities were classified as squamous or glandular and then further classified by the stage of dysplasia: atypical cells, mild, moderate, severe, and carcinoma.