Comparison of the clinical significance of the Papanicolaou test interpretations LSIL cannot rule out HSIL and ASC-H.

Despite the two-tiered classification of dysplasia in The Bethesda System (TBS), rare cases fall into the category squamous intraepithelial lesion (SIL) of indeterminate grade. These Pap tests are often interpreted as "LSIL/ASC-H" or "LSIL" with a comment indicating the presence of cells with features approaching HSIL. Patients with LSIL/ASC-H have a significant risk of CIN 2 or worse (29-61.5%) on follow-up cervical biopsies, similar to the risk of CIN 2 or worse in patients with ASC-H Pap tests (24-68%). The purpose of this study was to compare patients with ASC-H and LSIL/ASC-H Pap tests. Women with LSIL/ASC-H had a slightly lower incidence of CIN 2 or worse (PPV = 35.6%, 95% CI: 29.8-41.4%) on follow-up cervical biopsy than the control ASC-H group (PPV = 40.2%, 95% CI: 31.9-56.3%); this difference was not statistically significant. The difference in the distribution of the biopsy results between the two groups was statistically significant (P < 0.001). The current guidelines for the management of cervical cytologic abnormalities from the American Society for Colposcopy and Cervical Pathology (ASCCP) advocate similar treatment algorithms for both LSIL and ASC-H. The main difference is the option of cytologic follow-up or HPV testing for certain "special populations," as an alternative to colposcopy, for LSIL Pap test results. Based on our results, we recommend (1)LSIL/ASC-H to be added to TBS classification and (2) Pap test cases of LSIL/ASC-H may need to be clinically followed in a manner similar to ASC-H, i.e., colposcopy for all patients.