"Low-grade squamous intraepithelial lesion, cannot exclude high-grade squamous intraepithelial lesion" is a distinct cytologic category: histologic outcomes and HPV prevalence.

We examined the histologic outcomes and prevalence of high-risk human papillomavirus (HR-HPV) in women with liquid-based Papanicolaou (Pap) tests interpreted as "low-grade squamous intraepithelial lesion, cannot exclude high-grade squamous intraepithelial lesion" (LSIL-H) compared with the 2001 Bethesda System (TBS 2001) cytologic categories of LSIL, high-grade SIL (HSIL), and atypical squamous cells, cannot exclude HSIL (ASC-H). A computer search identified 426 LSIL, 86 ASC-H, 81 LSIL-H, and 110 HSIL cytologic interpretations during a 1-year period, each with up to 2 years of histologic follow-up. The risk of histologic cervical intraepithelial neoplasia (CIN) 2 or worse (CIN 2+) associated with LSIL-H (32/81 [40%]) was intermediate between LSIL (46/426 [10.8%]) and HSIL (72/110 [65.5%]), but not significantly different from ASC-H (23/86 [27%]). However, LSIL-H was more frequently associated with a definitive histologic diagnosis of any CIN (CIN 1+) than ASC-H (53/81 [65%] vs 35/86 [41%]). Moreover, the prevalence of HR-HPV was significantly greater in patients with LSIL-H than in patients with ASC-H (15/15 [100%] vs 43/73 [59%]). The histologic outcomes and HR-HPV prevalence associated with LSIL-H differ significantly from the established categories of TBS 2001 and provide evidence to support the recognition of LSIL-H as a distinct cytologic category.