What is the Difference Between ASCUS and LSIL

The key difference between ASCUS and LSIL is that ASCUS indicates the presence of slightly abnormal squamous cells in the cervix during a pap smear test that does not meet the criteria for a cancerous lesion, while LSIL indicates the presence of cervix squamous cells that exhibit early size and shape changes in the pap smear test, meeting the criteria for a potential cancerous lesion.

 A Pap test is done to look for precancerous cell changes or lesions on the cervix that might become cervical cancer later. A pap test result can be normal, unclear, abnormal, or unsatisfactory. A normal pap smear test shows healthy squamous cells on the surface of the cervix. An unclear pap smear test results may include ASCUS (atypical squamous cells of undetermined significance). An abnormal pap smear test result may include LSIL (low-grade squamous intraepithelial lesion) and HSIL (high-grade squamous intraepithelial lesion).

CONTENTS

1. Overview and Key Difference
2. What is ASCUS (Atypical Squamous Cells of Undetermined Significance)
3. What is LSIL (Low-grade Squamous Intraepithelial Lesion)
4. Similarities – ASCUS and LSIL
5. ASCUS vs. LSIL in Tabular Form
6. Summary – ASCUS vs. LSIL

What is ASCUS or Atypical Squamous Cells of Undetermined Significance?

Atypical squamous cells of undetermined significance or ASCUS is an unclear pap smear test result of the squamous cells of the cervix. In pap smear tests, it is common for test results to become unclear. The doctors sometimes may use other words like equivocal or inconclusive to describe this unclear result. All these names indicate the same test result. In the ASCUS test result, cervical cells (squamous cells) look like they could be abnormal. However, it is not clear if this is related to HPV (human papillomavirus). Moreover, the ASCUS test result also does not meet the diagnostic criteria for a cancer lesion.

Scientists predict ASCUS results could be related to life changes like pregnancy, menopause, or an infection. Furthermore, doctors can perform an HPV test that can help them find out if the cell changes in the cervix are related to HPV.

What is LSIL or Low-grade Squamous Intraepithelial Lesion?

An abnormal pap smear test result indicates that squamous cell changes were found on the cervix of women. This usually indicates that there is a likelihood of developing these changed cells into cervical cancer. Moreover, abnormal changes in the cervix are likely caused by HPV. These changes can be minor (lower grade) or serious (higher grade). Minor changes are known as LSIL (low-grade squamous intraepithelial lesion), and serious changes are known as HSIL (high-grade squamous intraepithelial lesion).

Most of the time, LSILs go back to normal on their own (after 18 to 24 months). But HSIL can turn into cancer if they are not removed. Furthermore, LSIL results are often associated with HPV. It is also called mild dysplasia or CIN1. Doctors might recommend colonoscopy after the first LSIL result in women.

What are the Similarities Between ASCUS and LSIL?

• ASCUS and LSIL are two different test results of a pap smear test of the cervix.
• Both these test results are obtained for women.
• After both these test results, doctors usually recommend performing an HPV test.
• Doctors normally do not recommend treatment regimes for women after getting the above types of pap smear test results and just continue observation.

What is the Difference Between ASCUS and LSIL?

ASCUS indicates the presence of slightly abnormal squamous cells in the cervix during a pap smear test that does not meet the criteria for a cancerous lesion, while LSIL indicates the presence of cervix squamous cells that exhibit early size and shape changes in the pap smear test, meeting the criteria for a potential cancerous lesion. Thus, this is the key difference between ASCUS and LSIL. Furthermore, ASCUS is often associated with life changes like pregnancy, menopause, or an infection. On the other hand, LSIL is often associated with HPV.

The infographic below presents the differences between ASCUS and LSIL in tabular form for side by side comparison.

Summary – ASCUS vs LSIL

Pap smear tests and HPV tests are screening tests that can help diagnose and prevent cervical cancer early. A pap smear test looks for precancer cell changes on the cervix. On the other hand, an HPV test looks for a virus called HPV, which can cause cell changes in the cervix. Normally, pap test results can be normal, unclear, abnormal, or unsatisfactory. ASCUS is an unclear pap smear test result, while LSIL is an abnormal pap smear test result. Furthermore, ASCUS indicates the presence of slightly abnormal squamous cells in the cervix during a pap smear test that does not meet the criteria for a cancerous lesion, while LSIL indicates the presence of cervix squamous cells that exhibit early size and shape changes in the pap smear test, meeting the criteria for a potential cancerous lesion. So, this summarizes the difference between ASCUS and LSIL.

Reference:

1. “Abnormal Cervical Cancer Screening Test Results.” ACOG.
2. Pietrangelo, Ann. “Low-Grade Squamous Intraepithelial Lesion (LSIL): What It Means.” Healthline.

Image Courtesy:

1. “Atypical squamous cell of undetermined significance – 1a — high mag” By Nephron – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Cytopathology of low-grade squamous intraepithelial lesion (LSIL)” By Mikael Häggström, M.D. – Own work (CC0) via Commons Wikimedia