What Does an Intraepithelial Lesion Mean?

Pap tests are performed on a sample of cells from the vagina or the cervix. The test looks out for any change in the sample cells as they can be indications of cancer or a condition that can lead to cancer. It is the best method to identify conditions that are precancerous and hidden tumors that result to cervical cancer. The results are based in a Bethesda system, where the term "intraepithelial lesion" is always included. Then what is an intraepithelial lesion? How does it affect our health?

The Bethesda System and Intraepithelial Lesion

Bethesda system is the basis of Pap smear tests and results. It was developed in Bethesda, Maryland at the National Institutes of Health (NIH). The system was the result of the 1988 National Cancer Institute workshop that was aimed at standardizing the pap results.

The Bethesda system (TBS) reports virginal or cervical cytological diagnoses that are used to report results from a pap smear.

1. Negative for the Intraepithelial Lesion – A Normal Result

Intraepithelial means infection of the surface layer of cells, while lesion means presence of abnormal tissue. Therefore, intraepithelial lesion in a Pap smear means that the cervix has an abnormality affecting its surface. If the result is negative for the intraepithelial lesion, this means all the cells have healthy shapes and sizes and the entire cervix is healthy.

2. Positive for the Intraepithelial Lesion – A Abnormal Result

This simply means that the sample showed something unusual. The cells might have been of different shapes and sizes, but this abnormal result doesn't necessarily indicate cancer. If this happens, it important to go for further testing.

An abnormal result can be caused by an infection or organisms in the cervix. Gonorrheal, trichomonas, yeast, herpes or chlamydial can cause cells in the cervix to be inflamed. However, once the infection is treated, the Pap smear results will be normal. If the results are positive because of an infection, you should go back in 2-3 month for another pap smear after treatment because cervical cancer can at times hide in an infection.

An abnormal result can also be due to other non-neoplastic findings. This is when benign cellular changes are reported. In other words, it indicates presences or response of an injury.

3. Other Abnormal Results of Pap Smear Test

There are other cell abnormalities that can be identified from a Pap smear test. They include:

1) Atypical Squamous Cells (ASC)

Squamous cells form on the surface of the cervix, which are thin and flat. TBS divides them into 2 groups: 

  • Atypical squamous cells of undermined significance (ASC-US): It is considered a mild infection and they do not appear completely abnormal. However, doctors are unsure about what these changes mean and it is sometimes linked to HPV. 
  • Atypical squamous cells without a high grade squamous intraepithelial lesion (ASC-H): The cells appear abnormal but doctors do not know what the change really means. ASC-H have a greater risk of being precancerous.

2) Atypical Glandular Cells

Located in the uterus lining or entrance in the center of the cervix, glandular cells produce mucus. These cells do appear to be abnormal but doctors are not sure what that means.

3) Low-grade squamous intraepithelial lesion (LSIL)

The term low-grade means that the cells are just beginning to change in shape and size. LSIL is considered to be a mild abnormality as a result of a HPV infection.

4) High-grade squamous intraepithelial lesion (HSIL)

The term high-grade means that the cells have evident changes in shape and size, which are distinct from the normal cells. HSIL is considered to be a serious abnormality and has a greater chance of becoming invasive cancer.

5) Adenocarcinoma in-situ

This is a precancerous condition where by the cancerous cells located in the cervix have not gone deeper into the tissue or spread out. Normally, this is treated through cone biopsy and in some cases the doctor might recommend removal of the uterus (Hysterectomy).