Atypical squamous cells of undetermined significance and low-grade squamous intraepithelial lesion: Diagnostic criteria and management

Since institution of the Bethesda system for reporting cervical and vaginal smears, there has been an increase in the number of smears reported to demonstrate atypical squamous cells of undetermined significance and low-grade squamous intraepithelial lesions. The cytologic changes associated with a smear reported to have these cells are discussed. It is apparent that the interpretation of the cellular changes defined as atypical squamous cells of undetermined significance are not clear and that there is a significant variation among cytopathologists as to the cytologic changes that should be incorporated under this classification. Data are presented on the frequency of this diagnosis in our laboratory and of the follow-up findings observed in a subgroup of patients whose smears were reported to demonstrated atypical squamous cells of undetermined significance. The cytologic and histopathologic changes observed with smears reported as demonstrating findings compatible with a low-grade squamous intraepithelial lesion are also discussed. A follow-up algorithm for the management of such patients is presented.