Squamous Epithelial Cells: What to Know

Squamous epithelial cells are a type of flat cell found throughout the body, including in the mouth, on the lips, and the cervix. They are also seen in the middle layers of the skin.

Squamous cell carcinoma is a form of cancer affecting the epithelium's squamous layers. It's the most common cancer of the oral cavity and also is common in the cervix and the skin.

This article discusses squamous epithelial cells and conditions that may affect them. It also explains what it means to have abnormal or atypical squamous cells found on a Pap smear or other tests.

What Does It Mean if You Have Abnormal Squamous Epithelial Cells?

Squamous cells often are involved in abnormal Pap smears. A diagnosis of atypical squamous cells of undetermined significance (ASC-US) indicates the presence of unusual cells that are not clearly benign or bad.

Abnormal Pap smear results are sometimes diagnosed as squamous intraepithelial lesions. This is a very specific diagnosis of an abnormal Pap smear considered precancerous.

When you receive this diagnosis, it means that the squamous epithelial cells found in the cervix have taken on an abnormal morphology, or shape but aren't necessarily cancerous. In fact, low-grade squamous intraepithelial lesions (LSIL) often heal themselves without intervention.

These lesions are also sometimes known as cervical dysplasias or cervical intraepithelial neoplasia (CIN), High-grade squamous epithelial lesions (HSIL) are more likely to become cervical cancer than LSIL. However, they can also regress.

There are several other Pap smear diagnoses. These include ASC-H, atypical squamous cells, cannot exclude HSIL. As with ASCUS, the meaning of ASC-H is unclear. However, cells diagnosed as ASC-H are more likely to be problematic than those diagnosed as ASCUS.

There is also a Pap smear diagnosis of atypical glandular cells (AGC). This diagnosis refers to changes in the glandular cells in the cervix, which are not part of the squamous epithelium. Changes in the glandular cells generally require more intensive treatment than changes in squamous cells.

Squamous Cells, Cervical Cancer, and HPV

Most cervical cancers and pre-cancers are caused by infections with human papillomavirus (HPV). HPV infects and transforms the squamous cells of the cervix. It can also infect and transform the cells of other tissues in the body.

HPV is transmitted through skin-to-skin contact, including oral, anal, and vaginal sex.

Depending on circumstances, over time, healthy cells may replace these transformed cells or they may continue growing abnormally and become cancerous.

Most cervical HPV infections do not lead to cervical cancer as the body is often capable of eliminating these infections on its own.

Other Squamous Cell Cancers and HPV

HPV infection is also associated with squamous cell cancers in other locations. They include cancers of the head and neck, the vulva, the penis, and the anus. In fact, some scientists estimate that four out of every five cancers are caused by HPV.

Fortunately, HPV-associated cancers have been found to be more treatable than other squamous cell cancers—at least in the head and neck.

The risk of HPV infection can also be reduced by vaccination. Cervarix and Gardasil are two vaccines that have been shown to reduce the risk of HPV infection. However, they are most effective when they are given before young people become sexually active.

If you are a young adult or the parent of a young adult, talk to your healthcare provider about whether the HPV vaccine is a good option. The HPV vaccine is currently recommended as a routine vaccination for young men and women between the ages of 11 and 12. It can be given up until age 26, depending on the circumstances.

How Are Abnormal Squamous Epithelial Cells Treated?

Treating abnormal squamous epithelial cells depends on the specific diagnosis. Low-grade squamous intraepithelial lesions (LSILs) found in a Pap smear may normalize on their own. However, a closer follow-up with more frequent testing may be necessary.

But when abnormal epithelial cells appear to have a risk of being concerning or cancerous, treatment involves exercising or removing the abnormal tissue.

A common excisional method is known as a loop electrosurgical excision procedure (LEEP), where abnormal cells are cut away by a wire loop that's heated with an electric current. A cone biopsy is another common way to diagnose or treat these abnormal cells.

Urine Test for Epithelial Cells

A urinalysis is a standard test that analyzes the substances in your urine. This includes the amount of epithelial cells your urine contains.

While it's normal to have small amounts of epithelial cells in your urine, large amounts may signify something is wrong, such as a contaminated specimen, an infection, or another medical condition.

What to Expect

A urine sample is needed for an epithelial cells in urine test. You will receive a container where the urine is collected and given instructions on how to take the sample to ensure it does not get contaminated.

Typically, you will not need to fast or do other preparations before taking the test unless instructed by your healthcare provider.

Results

Results of cell amounts are usually reported as approximates, such as "few," "moderate," or "many" cells. "Few" cells mean that your epithelial cell numbers are considered to be in the normal range, while "moderate" or "many" cells may be a sign of a medical condition like:

• Urinary tract infection (UTI)
• Liver disease
• Bladder or urethral cancer

Know that having results in the abnormal range doesn't always mean you have a medical condition. Your healthcare provider will typically order more tests to form a final diagnosis.

Summary

Squamous epithelial cells are found in the skin, mucous membranes, and tissues lining your organs. Abnormal squamous epithelial cells are often detected on Pap smears and are associated with HPV-related cancers.

Squamous epithelial cells found on a urine test can indicate a UTI, liver disease, or cancer of the urinary tract. They may also indicate, however, that the test was contaminated and needs to be repeated.

Receiving abnormal Pap smear results can be upsetting. However, oftentimes, these cervical cell changes diagnosed as ASC-US or pre-cancerous lesions clear up on their own within a year or two.

If you have an abnormal urine test or Pap smear, your healthcare provider will discuss your options for further testing and treatment. Often, a wait-and-see approach, along with more frequent monitoring, is the recommended course of action.