Squamous epithelial cells are thin, flat cells that form part of the epithelium, which is the tissue that covers the outside of the body and lines many internal surfaces. These cells are found in several areas, including the skin, mouth, throat, esophagus, anus, cervix, vagina, blood vessels and body cavities.
Squamous epithelial cells may be found in different types of medical samples, such as urine samples, Pap tests and tissue samples from areas lined by squamous epithelium. Their meaning depends on where the sample came from, how the cells look and whether other abnormal findings are present.
In many cases, squamous epithelial cells are normal and do not mean there is a disease. However, high numbers in urine, abnormal findings in a Pap test or atypical-looking squamous cells may need repeat testing, follow-up exams or treatment depending on the cause.
Normal ranges
The normal amount of squamous epithelial cells depends on the type of test and the specimen being analyzed. These cells may be expected in samples taken from areas that naturally contain squamous epithelium, such as the cervix, vagina, mouth, skin or lower urinary tract.
In urine tests, a small number of squamous epithelial cells is usually considered normal. Some reports describe the amount as “few,” “some,” “moderate” or “many,” while others give a number per high-power field.
A general reference used in some urine reports is:
- Few: up to 3 epithelial cells per high-power field
- Some or moderate: 4 to 10 epithelial cells per high-power field
- Many: 10 or more epithelial cells per high-power field
These ranges can vary by laboratory. For this reason, results should be interpreted together with the lab’s reference range and other findings in the same test.
In Pap tests, squamous epithelial cells are expected because the cervix contains these cells. In this type of specimen, the result depends less on the number of cells alone and more on whether the cells look normal, atypical or abnormal.
What do results mean?
The meaning of squamous epithelial cells depends on the specimen type. In some samples, they are a normal finding because the sample was taken from an area where these cells naturally exist.
In a urine test, squamous epithelial cells often come from the lower urinary tract, genital area or skin around the urethra. A high number may suggest that the urine sample was contaminated during collection, especially if the sample also has mixed bacteria or unclear signs of infection.
In a Pap test, squamous epithelial cells are part of the normal cervical sample. The report becomes more important when these cells show abnormal changes, such as atypical squamous cells or squamous intraepithelial lesions.
In specimens from other areas, such as the mouth, throat, esophagus, anus, vagina or skin, squamous epithelial cells may simply reflect the type of tissue being sampled. Abnormal-looking squamous cells may need further evaluation, depending on the location and test result.
Causes of high squamous epithelial cells
High squamous epithelial cells can happen when many of these cells are present in the specimen. The cause depends on the type of sample and the part of the body being tested.
1. Sample contamination
In urine tests, high squamous epithelial cells commonly happen because cells from the skin, genital area, vagina or foreskin enter the sample. This can occur if the genital area is not cleaned before collection, if the inside of the cup is touched or if the first part of the urine stream is collected.
A contaminated urine sample may be harder to interpret. In some cases, the test may need to be repeated with a clean-catch midstream sample.
2. Normal shedding of cells
Squamous epithelial cells naturally shed from surfaces that contain this type of tissue. Because of this, they may appear in samples from the skin, mouth, throat, cervix, vagina, anus and other lined surfaces.
Finding these cells is not always abnormal. The result should be interpreted based on the sample site and whether the cells look normal under the microscope.
3. Urinary tract infection or inflammation
In urine samples, squamous epithelial cells may appear with other signs of a urinary tract infection, such as bacteria, white blood cells, nitrites or leukocyte esterase. However, squamous epithelial cells alone do not confirm a urinary tract infection.
Inflammation or irritation in the urinary or genital area may also increase the number of cells shed into a sample.
4. Menopause-related changes
Menopause may be linked to changes in genital and urinary tissues. These changes can affect urine findings and may contribute to epithelial cells appearing in the sample.
5. Cervical cell changes
In Pap tests, abnormal squamous epithelial cells may be related to HPV infection, inflammation or cervical cell changes. These results are classified using reporting systems such as the Bethesda system.
Some abnormal results are mild and may only need repeat testing. Others may need HPV testing, colposcopy, biopsy or treatment, depending on the type and severity of the cell changes.
Possible symptoms
Squamous epithelial cells do not usually cause symptoms. Symptoms, when present, are usually related to the condition or body area being tested.
If a urinary tract infection is present, symptoms may include pain or burning when urinating, frequent urination, urgent urination, cloudy urine, strong-smelling urine or lower abdominal discomfort.
If there is irritation or inflammation in the genital area, symptoms may include itching, burning, discomfort or unusual discharge. These symptoms should be assessed together with the test result and medical history.
Abnormal squamous cells on a Pap test often do not cause symptoms. This is one reason routine cervical cancer screening is important, as it can find cell changes before symptoms appear.
Treatment options
Squamous epithelial cells do not need treatment by themselves. Treatment depends on why the cells were found and whether the test shows signs of infection, inflammation or abnormal cell changes.
If a urine result is likely due to contamination, the usual next step is to repeat the test with proper collection technique. This may include cleaning the genital area, avoiding contact with the inside of the cup and collecting urine from the middle of the stream.
If a urinary tract infection is confirmed, treatment may include antibiotics prescribed by a doctor. The choice of treatment depends on the person’s symptoms, test results and medical history.
If inflammation or irritation is suspected, treatment depends on the cause. This may include treatment for infection, vaginal or genital irritation, menopause-related changes or another condition found during evaluation.
If a Pap test shows abnormal squamous epithelial cells, treatment depends on the type and severity of the change. Mild changes may only require monitoring or repeat testing, while higher-grade changes may need colposcopy, biopsy or a procedure to remove abnormal tissue.