What is a low-grade squamous intraepithelial lesion?

Low-grade squamous intraepithelial lesions (LGSIL or LSIL) are abnormal growths in the superficial layer of the cervix, particularly in the transformation zone. They can be detected by the Pap test (Pap), which checks for changes in the cells of the cervix and increases early detection of malignancy changes. Since the introduction of the Pap test in the mid-20th century, cases of cervical cancer have been declining, although it remains a leading cause of death among women in developing countries.

Samples taken from a Pap smear are examined under a microscope. The examiner looks for a low-grade squamous intraepithelial lesion, which is characterized by dysplasia. Discovering precancerous lesions is important because they can be treated to prevent progression to full-blown cancer. The Bethesda system classifies precancerous cervical cells into low-grade squamous intraepithelial lesions and high-grade squamous intraepithelial lesions (HSIL). If not managed properly, approximately 20% of low-grade squamous intraepithelial lesions can progress to their high-grade counterparts, and 1% of these become invasive cancers.

Dysplasia is a term that refers to the lack of uniformity between cells of the same origin and the loss of their architectural orientation. In cervical dysplasia, cell nuclei appear hyperchromatic or denser than normal, and are distinctly large relative to cell size. Dysplastic cells look different from neighboring normal cells. They exhibit pleiomorphism, which simply means that they have variable shapes.

The appearance of a low-grade squamous intraepithelial lesion is associated with human papillomavirus (HPV) infection. According to studies, the risk of LSIL and HSIL depends on exposure to high-risk human papillomaviruses. The subtypes, which are considered low risk, are HPV 6 and 11, while those that are considered high risk are HPV 16 and 18. Like other HPV variants, these viruses are transferred through sexual contact. Having multiple sexual partners, being very young at first sexual contact, being in lower socioeconomic strata, and having persistent infection with high-risk HPV subtypes are considered the main risk factors for the formation of LSIL and HSIL.

To provide a definitive diagnosis of low-grade squamous intraepithelial lesion, the cervix is ​​visualized through a microscope using a method called colposcopy. A biopsy may be done to rule out the possibility of malignancy. The goal of LSIL treatment is to kill the abnormal cells on the cervical surface. Cryotherapy, or the application of very low temperatures to the cervical surface, is often performed. When abnormal cells are spread over a wide area, the entire area may be removed to lower the risk of cancer.

Go up