Low-grade squamous intraepithelial lesion, cannot rule out high-grade lesion: Diagnosis, histological outcomes and human papillomavirus results

Background: The 2014 Bethesda System for Reporting Cervical Cytology classifies squamous intraepithelial lesions (SILs) of cervix into two main categories: low-grade SIL (LSIL) and high-grade SIL (HSIL). In some clinical practices, the LSIL cannot rule out high-grade lesion (LROH) interpretive category is used in cases with LSIL and findings that may raise the possibility of HSIL. Our purpose is to assess follow-up histopathology and high-risk human papillomavirus (hrHPV) results in patients with LROH, in comparison with LSIL, atypical squamous cells, cannot rule out HSIL (ASC-H), and HSIL in our institution. Design: Cervical Papanicolaou tests with LROH, LSIL, ASC-H and HSIL interpretation, surgical follow-up, and hrHPV status were retrieved from the computer database from May 2014 to December 2016. Results: Of 109 963 total Papanicolaou tests, LROH comprised 0.3%, LSIL 3.1%, ASC-H 0.2% and HSIL 0.4%. Only 3272 cases with surgical diagnoses were included in the study. The most common histological outcome for ASC-H was cervical intraepithelial neoplasia (CIN)2/3 (32.6%); LSIL was CIN 1 (45.7%); LROH was CIN 1 (46.7%) and HSIL was CIN 2/3 (64.4%). For LROH and LSIL, 31.1% and 7.5% respectively, had CIN 2/3. Approximately 79% of cases were hrHPV positive. Of LROH cases with surgical follow-up, 86.9% tested hrHPV positive, accounting for the second most common positive group after HSIL (92.6%). Conclusion: In our study cohort, LROH interpretation is associated with a higher number of CIN 2 or higher lesions on follow-up compared to patients with LSIL (P < 0.0001), and is associated with a significant percentage of positive other hrHPV, supporting LROH as a useful diagnostic category that triggers appropriate follow-up in affected women.