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.