September 25, 2023
The transformation zone is a part of the cervix where the squamous cells that make up the ectocervix meet the glandular cells that make up the endocervix. In this area of the cervix, the glandular cells that make up the endocervix are slowly replaced by squamous cells. This process is called squamous metaplasia. As a result, the ectocervix becomes larger and the endocervix becomes smaller over time. The transformation zone is a normal part of the cervix.
The transformation zone is important because most pre-cancerous conditions, such as low grade squamous intraepithelial lesion (LSIL) and high grade squamous intraepithelial lesion (HSIL) as well as cancers such as squamous cell carcinoma, start in this area of the cervix. These conditions are almost always caused by the human papillomavirus (HPV), which infects cells in this area.
This article was written by doctors to help you read and understand your pathology report. Contact us if you have a question about this article or your pathology report.