Reporting of "LSIL with ASC-H" on cervicovaginal smears: is it a valid category to predict cases with HSIL follow-up?

Recently it has been shown that there is a 15-30% risk of associated cervical intraepithelial neoplasia (CIN 2-3 or greater) for a low-grade squamous intraepithelial lesion (LSIL) diagnosis. We tried to define a subgroup of "LSIL with atypical squamous cells of undetermined significance. High-grade squamous intraepithelial lesion (LASC-H)" in cervicovaginal screening which may aid in predicting the cases associated with high risk cannot be ruled out. In the years between 2001 and 2003 a total of 21,342 cervicovaginal smears were evaluated. The smears with pure LSIL and LASC-H diagnosis which had histologic follow-up were selected. The cases with diagnosis of LASC-H contained numerous typical cells of LSIL and only a few cells with features suggesting high-grade squamous intraepithelial lesion (HSIL). Eight (61%) of 13 cases with a diagnosis of LASC-H but three (11%) of 27 cases with a diagnosis of pure LSIL resulted in CIN 2-3 histology (p < 0.05). Diagnosis of LASC-H may be a valid diagnostic category in distinguishing patients with LSIL that would have HSIL in follow-up.