What does low-grade squamous intraepithelial lesion (LSIL) mean?

Low-grade squamous intraepithelial lesion (LSIL) is a precancerous condition, but it is not yet cervical cancer. Most individuals with LSIL will experience spontaneous regression to normal epithelium—particularly those with low-grade lesions. Some patients may remain stable with no progression, while a small proportion may progress to carcinoma in situ or microinvasive carcinoma. So, what exactly does “low-grade squamous intraepithelial lesion” mean? Below is an overview.

What Does Low-Grade Squamous Intraepithelial Lesion Mean?

Low-grade squamous intraepithelial lesion is a pathological diagnosis established via cervical liquid-based cytology, abbreviated as LSIL. LSIL results from infection with either high-risk or low-risk human papillomavirus (HPV) types and encompasses two main histological patterns: (1) HPV-induced cytomorphologic changes—characterized by koilocytes (“halo cells”)—and (2) mild dysplasia without koilocytosis (non-koilocytic mild dysplasia). If high-risk HPV infection is detected and colposcopy reveals abnormal cervical findings—such as thick acetowhite epithelium and failure to stain with iodine (Schiller test)—a diagnosis of cervical precancer or invasive cancer should be considered. In such cases, cervical biopsy is mandatory. When indicated, endocervical curettage (ECC) may also be performed to obtain tissue samples from both the ectocervix and endocervical canal for histopathological examination. Final management decisions are based on the pathology report.

Knowledge Extension: Treatment Options for Low-Grade Squamous Intraepithelial Lesion include biopsy, physical ablation therapies, and total hysterectomy. Details follow:

1. Biopsy

Upon detection of LSIL, colposcopic examination of the cervix is required. Targeted biopsies are taken from suspicious areas under colposcopic guidance to determine whether high-grade intraepithelial neoplasia (HSIL) or invasive cervical cancer is present.

2. Physical Ablation Therapies

If colposcopy is satisfactory (i.e., the entire transformation zone is fully visualized), cryotherapy or laser ablation may be employed. However, if colposcopy is unsatisfactory (i.e., the transformation zone cannot be fully assessed), cervical conization is recommended.

3. Total Hysterectomy

When histopathology confirms cervical intraepithelial neoplasia grade 2 (CIN 2) or grade 3 (CIN 3), further management depends on post-loop electrosurgical excision procedure (LEEP) pathology results. CIN 3 involving glandular epithelium raises suspicion for carcinoma in situ. For women who have completed childbearing, total hysterectomy may be considered. Thus, initial colposcopically directed biopsy remains essential to guide subsequent therapeutic decisions.

The above provides an explanation of what low-grade squamous intraepithelial lesion means. We hope this information is helpful to you.