Atypical squamous cells of undetermined significance (ASCUS), low-grade squamous intraepithelial lesion (LSIL), high-grade squamous intraepithelial lesion (HSIL) and histology.

Objective: A new terminology for cytologic diagnosis of cervical lesions has been introduced by Bethesda System. This includes: 1) Atypical squamous cells of undetermined significance (ASCUS), 2) Low-grade squamous intraepithelial lesion (LSIL), 3) High-grade squamous intraepithelial lesion (HSIL), 4) squamo-cellular carcinoma. The aim of this study was to assess the correlation between the colpocytologic test (Pap psmear), the histologic response and colposcopy.
Methods: We re-examined the cytologic results of 447 patients who underwent routine cytologic tests, with a diagnosis of various grades of atypia, from ASCUS to HSIL. A histologic test was carried out on a colposcopic basis in 210 cases and cytologic results were correlated with the histologic and colposcopic pictures.
Results: For ASCUS the histology was positive in 19.1% (31/163) of cases and negative in 10.4% of the colposcopically positive cases (17/163), while in the remaining 70.5% (115/163) the colposcopy resulted negative. In LSIL with the presence of human papillomavirus (HPV) the histologic findings, confirmed the cytologic result in 35.8% (48/134) while in the group of cervical intraepithelial neoplasia (CIN I) results corresponded in 40.6% (41/101). In high squamous intraepithelial lesions there was an histologic confirmation in 59.2% (29/49).
Conclusions: The data obtained indicate an increase in positive histology results from the types of low grade (ASCUS-LSIL) to those of a high grade (HSIL). Our results indicate that the presence of ASCUS should be assessed colposcopically and histologically, where indicated.