The Bethesda System (TBS) for Reporting CervicaVVaginal Cytologic Diagnoses was developed at a National Cancer Institute (NCI)-sponsored workshop in December 1988 to provide uniform diagnostic terminology that would facilitate communication between the laboratory and the clinician. The format ofTBS report includes a descriptive diagnosis and an evaluation of specimen adequacy. TBS was designed to be flexible so that it could evolve in response to changing needs in cervical cancer screening as well as to advances in the field of cervical pathology. Subsequently, a second workshop was held in April 1991 to evaluate the impact of TBS in actual practice and to amend and modify it where needed. One of the major recommendations of this second meeting was that precise criteria should be formulated for both the diagnostic terms and for the descriptors of specimen adequacy. That is the intended purpose of this monograph. The classification used in TBS is not a histogenetic one, but rather a nomenclature designed to facilitate categorization and reporting of cyto logic diagnoses. The overall diagnosis, as in the World Health Organiza tion (WHO) system, is based on the most abnormal cells present regardless of their number. In addition, it should be noted that the site of origin of an abnormality detected in a cervicaVvaginal cytologic sample cannot always be specified because morphologically identical tumors may arise in the vagina, cervix, endometrium, or ovary.
