Living with uncertainty: equivocal Pap test results and the evolution of ASC terminology.

Communication of equivocal findings and their significance has been a significant challenge related to Pap testing throughout its history. Terminology to report these findings has changed considerably to accommodate the changes in understanding of cervical neoplasia, and to accommodate new management strategies, tests, and technologies. This article reviews the evolution of terminology for equivocal Pap test findings from the original Papanicolaou classification to the current the Bethesda System 2001 atypical squamous cells terminology, the implication and use of these terms, and the changing landscape of cervical neoplasia screening, which prompted these terminology changes. Emerging issues related to improving risk stratification through the introduction of additional terms and the impact of human papillomavirus testing may alter terminology of equivocal findings in the future.