Slightly abnormal cells are found on the surface of the cervix. Low-grade squamous intraepithelial lesion is caused by certain types of human papillomavirus (HPV) and is a common abnormal finding on a Pap test. It usually goes away on its own without treatment but sometimes the abnormal cells become cancer and spread to nearby normal tissue. Low-grade squamous intraepithelial lesion is sometimes called mild dysplasia. Also called LSIL.