The Utility of ‘Low-Grade Intraepithelial Lesion, Cannot Exclude High Grade’ Diagnosis: A Single Institution’s Experience

Abstract

Objective: Squamous intraepithelial lesions (SILs) are classified as low-grade SIL (LGSIL) and high-grade SIL (HGSIL). ‘LGSIL cannot exclude high grade’ (LGSIL-H) interpretive category has been used in cases where findings exceed criteria for LGSIL, but do not fulfill the criteria for HGSIL. This study analyzed follow-up histology of LGSIL-H cases and compared the follow-up results of LGSIL-H with LGSIL to determine the utility of LGSIL-H category using a single institution’s experience. Study Design: Pap smears with LGSIL-H interpretation from 2005 to 2008 were retrieved. Histological follow-up results for LGSIL-H cases were analyzed and compared to the follow-up results of LGSIL cases. Results: Cases with LGSIL-H interpretation (311) comprised 0.18% of all cases (170,307). Follow-up was available for 144 patients and 13.2% had benign findings, 51.4% had cervical intraepithelial neoplasia (CIN) 1, and 35.4% had CIN 2 or higher. In comparison, of 425 patients with LGSIL, 22.6% had benign findings, 71% had CIN 1 and 6.4% had CIN 2 or higher. Conclusion: A significantly greater number of patients with LGSIL-H interpretation had a CIN 2 or higher lesion on follow-up compared to patients with LGSIL. This suggests LGSIL-H may be a useful diagnostic category.

Is the Low-Grade Squamous Intraepithelial Lesion/Atypical Squamous Cells Cannot Exclude High-Grade Squamous Intraepithelial Lesion Category Associated with Cervical Intraepithelial Neoplasia 2?

“…Such cases are referred to as SILs of indeterminate grade in the TBS 2001 manual, but there was not a specific diagnostic category including the cervical smears which exhibit LSIL and ASC-H cytomorphology in the abbreviated versions of TBS 2001 [10,11]. There have been a number of studies focusing on this subset of cases, and many authors believe LSIL/ASC-H should be considered as a distinct diagnostic category [2,3,4,5,6,7,8] in TBS.…”

“…from 29 to 40.7% [1,5,6,7,8,9,12,13], and a small number of studies showed higher rates of CIN2/CIN3 for LSIL/ASC-H, i.e. from 45 to 61% [2,3,4].…”

“…These cases typically contain numerous cells of LSIL and only a few cells with features suggesting HSIL. There is a great deal of published literature on how well a finding of LSIL/ASC-H cytology predicts HSIL on subsequent histological examination [1,2,3,4,5,6,7,8]. Nearly all of the articles recommend that LSIL/ASC-H be a separate category in TBS and that a follow-up colposcopy should be performed clinically for all of these patients.…”

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

“…It has been proposed that these intermediate morphological patterns might be better designated with a diagnostic term that better conveys these findings. Many terminologies have been used, such as LSIL, cannot exclude HSIL (LSIL‐H), LSIL cannot rule out high‐grade lesion (LROH), LSIL with ASC‐H , LSIL with rare atypical cells suggestive but not diagnostic of HSIL , LSIL with an additional note alerting the provider to the presence of cells suggestive of HSIL , among others . However, this intermediate category is not part of the TBS 2014 reporting system and its use is discouraged.…”

“…Several reported studies have indicated that patients with LROH/LSIL‐H appeared to have an intermediate risk of harbouring or developing high‐grade squamous lesions on biopsy and a different HPV prevalence compared with LSIL and ASC‐H, ranging from 22.8% to 59% of cases . Because of the increased incidence of high‐grade lesions found on histology, comparable to patients with HSIL, it has been proposed that these patients may require a clinical management similar to HSIL diagnosis …”