Low-grade squamous intraepithelial lesion (LSIL) is a non-cancerous, sexually transmitted disease caused by infection with a virus called the human papillomavirus (HPV). This condition may affect both women and men. In women, LSIL commonly involves the cervix, vulva, or vagina. In both women and men, LSIL may also involve the anal canal and peri-anal skin. Your doctor may perform a test called a Pap smear or biopsy to look for LSIL, and the diagnosis is made after the tissue sample is examined under the microscope by a pathologist.
LSIL develops after the specialized squamous cells on the surface of tissue in these regions become infected by the virus. Infected cells show an abnormal pattern of development called dysplasia. Although LSIL is considered a non-cancerous disease, there is a very small risk that it will turn into 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.