Low grade squamous intraepithelial lesion (LSIL) of the vagina

by Emily Goebel, MD FRCPC
June 6, 2022

What is low grade squamous intraepithelial lesion (LSIL) of the vagina?

Low grade squamous intraepithelial lesion (LSIL) of the vagina is a non-cancerous, sexually transmitted disease caused by infection with human papillomavirus (HPV). This condition may affect both women and men. In addition to the vagina, LSIL can also affect the cervix and vulva. In both women and men, LSIL may also involve the anal canal and peri-anal skin.

What causes low grade squamous intraepithelial lesion in the vagina?

LSIL in the vagina is caused by human papillomavirus (HPV). The virus infects the specialized squamous cells on the inside surface of the vagina which leads to an abnormal pattern of development called dysplasia.

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

LSIL is not a type of cancer but there is a very 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.