A diagnosis of a low grade squamous intraepithelial lesion, or LSIL, can understandably cause concern. This finding indicates that mild changes have been observed in the cells on the surface of the cervix. While LSIL is an abnormal result, it does not mean cancer is present. Instead, it represents a common cellular change that often resolves on its own without intervention.
What Low Grade Squamous Intraepithelial Lesion Means
A low grade squamous intraepithelial lesion (LSIL) refers to mildly atypical cell growth on the surface of certain organs, most commonly the cervix. The term “squamous” describes the flat, thin cells that form the outer layer of the cervix. “Intraepithelial” means these abnormal cells are confined to the surface layer and have not invaded deeper tissues. “Low grade” indicates that the cellular changes are mild. This condition is also known as mild dysplasia or cervical intraepithelial neoplasia type 1 (CIN 1).
The primary cause of LSIL is infection with the human papillomavirus (HPV). HPV is a very common sexually transmitted infection, and most people will be infected with it at some point in their lives. While many HPV infections clear up naturally due to the body’s immune response, persistent infections with certain types of HPV can lead to cellular changes like LSIL. LSIL is a common finding, with one study estimating that around 1.9% of women received an LSIL diagnosis after a Pap test between 2013 and 2019. It is considered a precancerous condition, meaning it has the potential to become cancer, but this progression is not guaranteed and often takes many years.
How LSIL is Identified
LSIL is identified through routine cervical cancer screening tests. The primary screening method is the Pap test, also known as a Pap smear. During a Pap test, cells are collected from the cervix and examined under a microscope for any abnormal changes. An LSIL result on a Pap test indicates that these collected cells show mild abnormalities.
If a Pap test shows an abnormal result like LSIL, an HPV test may also be performed on the same sample. HPV testing helps determine if high-risk types of the virus, which are more commonly associated with cervical cancer, are present. If abnormal results persist or high-risk HPV is detected, the next step involves a procedure called a colposcopy. During a colposcopy, a healthcare provider uses a magnifying device to closely examine the cervix.
If suspicious areas are observed during the colposcopy, a small tissue sample, called a biopsy, is taken. This biopsy is then sent to a laboratory for further analysis to confirm the diagnosis and determine the extent of the cellular changes.
Next Steps After an LSIL Diagnosis
Following an LSIL diagnosis, the management approach involves watchful waiting, also known as active surveillance, rather than immediate treatment. This is because a significant majority of low-grade lesions resolve spontaneously within 24 months, particularly in younger individuals. The body’s immune system frequently clears the HPV infection, leading to the return of normal cervical cells.
Regular follow-up tests are part of this management strategy. These include repeat Pap tests and HPV tests, performed at 6-month or 12-month intervals. The goal of these follow-up appointments is to monitor the cellular changes and ensure that the lesion regresses or does not progress to a higher grade.
Further intervention, such as a colposcopy with directed biopsies, is considered if the LSIL persists, if high-risk HPV types are present, or if there are other concerning factors. For most individuals with LSIL, the prognosis is favorable.