MyPathologyReport
December 18, 2023
Low grade squamous intraepithelial lesion (LSIL) is an abnormal growth caused by infection with human papillomavirus (HPV). The abnormal growth seen in LSIL is an example of dysplasia. It commonly involves the cervix, vagina, vulva, penis, or anal canal. This condition may affect both women and men.
The virus infects squamous cells found on the surface of the tissue 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.
Can low grade squamous intraepithelial lesion turn into cancer over time?
LSIL is considered a precancerous condition because it can turn into a type of cancer called squamous cell carcinoma over time. LSIL can also change into a more advanced precancerous condition called high grade squamous intraepithelial lesion (HSIL). However, it is important to know that the risk of LSIL turning into cancer is low, and for most people with LSIL, the immune system will remove the infected cells and the tissue will return to normal over time.
How is this diagnosis made?
Doctors often perform a test called a Pap test to look for LSIL in the cervix and the anal canal. The diagnosis can also be made when a larger tissue sample is removed during a procedure called a biopsy or an excision. The samples are then sent to a pathologist for examination under a microscope.
What does low grade squamous intraepithelial lesion look like under the microscope?
Compared to normal, healthy squamous cells, the abnormal squamous cells in LSIL are larger and darker and the nucleus (the part of the cell that holds the genetic material) often has an irregular shape. Pathologists sometimes call these cells koilocytes or use the term koilocytic change to describe these microscopic features. If immunohistochemistry is performed, the cells in LSIL are typically negative for p16.
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.
Related articles on MyPathologyReport
High grade squamous intraepithelial lesion (HSIL)
Human papillomavirus (HPV)
Koilocytes
Other helpful resources
Atlas of pathology
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