Low grade squamous intraepithelial lesion of the vagina

by Emily Goebel, MD FRCPC
December 18, 2023

Low grade squamous intraepithelial lesion (LSIL) in the vagina is an abnormal growth caused by infection with human papillomavirus (HPV). The abnormal growth seen in LSIL is an example of dysplasia. In addition to the vagina, LSIL can also affect the anal canal, vulva, and cervix. In men, LSIL can affect the penis and scrotum.

The virus infects squamous cells found on the inside surface of the vagina which over time develop genetic changes that lead to LSIL.  The squamous cells form a thin layer of tissue called the epithelium. The term “intraepithelial” means that the abnormal cells in LSIL are still located entirely within the epithelium.

Is low grade squamous intraepithelial lesion of the vagina a type of cancer?

LSIL is not a type of cancer but there is a small risk that it will turn into a type of vaginal cancer called squamous cell carcinoma over time. However, for most patients with LSIL, the immune system will remove the infected cells and the tissue will return to normal. High grade squamous intraepithelial lesion (HSIL) is a related condition that is also caused by HPV. However, compared to LSIL, the risk of developing cancer from HSIL is much higher.

How is the diagnosis of low grade squamous epithelial lesion in the vagina made?

The diagnosis of LSIL in the vagina is usually made after a small sample of tissue is removed in a procedure called a biopsy. When examined under the microscope, squamous cells infected with HPV are much larger than normal squamous cells and are called koilocytes. Biopsies from the vulva and cervix may also be taken to look for a similar condition in those areas. Additional treatment is not always required.

About this article

This article was written by doctors to help you read and understand your pathology report. Contact us if you have questions about this article or your pathology report. For a complete introduction to your pathology report, read this article.

Other helpful resources

Atlas of pathology
US Centers for Disease Control and Prevention
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