What is squamous epithelium?

Squamous epithelium is a thin layer of tissue made up of flat cells called squamous cells. These cells form a protective barrier on the surface of various organs and tissues throughout the body, helping to protect the underlying tissues from injury, infection, and irritation.

Where is squamous epithelium found in the body?

Squamous epithelium is normally found in several areas of the body, including:

• Skin: It covers the entire outer surface of your body, protecting against injuries, bacteria, and other harmful substances.

• Mouth and throat: It lines your oral cavity, esophagus (food pipe), and the pharynx (throat area), protecting them from food, liquids, and environmental irritants.

• Respiratory tract: Squamous epithelium lines parts of the airways, including the nasal cavity, larynx (voice box), trachea (windpipe), and bronchi (smaller airways), helping to guard against infection.

• Genital and anal areas: It lines surfaces such as the vagina, cervix, and anus, protecting them from infection and injury.

Is squamous epithelium normal?

Yes, squamous epithelium is a normal and essential part of your body. However, its thickness and properties can vary depending on its location and the specific protective functions needed in each area. For instance, the squamous epithelium on your skin is thicker and tougher than the squamous epithelium inside your mouth or respiratory tract.

What does it mean if squamous epithelium is described as reactive?

If squamous epithelium is described as reactive, it means the cells appear abnormal under a microscope because they have been injured or irritated. This reaction might be due to:

• Infection (caused by viruses, bacteria, or fungi)

• Physical stress or injury (such as rubbing or scraping)

• Exposure to chemicals, medications, or other irritants

A reactive change is not cancerous. Reactive changes usually resolve when the source of irritation or injury is removed or treated.

What does it mean if squamous epithelium is described as metaplastic?

Metaplastic squamous epithelium refers to a change in which normal cells in a particular area are replaced by squamous cells. This usually happens as an adaptive response to chronic irritation or inflammation. For example, the lining of your bladder normally contains specialized cells called urothelial cells. If these urothelial cells are repeatedly irritated or inflamed, they may be replaced by squamous cells (a process known as metaplasia).

Metaplasia is not cancer, but your doctor might recommend monitoring or further evaluation because it indicates ongoing irritation.

What is the most common type of cancer that develops from the squamous epithelium?

The most common type of cancer arising from squamous epithelium is squamous cell carcinoma. This cancer develops when normal squamous cells become abnormal, growing uncontrollably and invading nearby tissues. It can occur in various parts of the body, including the skin, mouth, throat, lungs, cervix, vagina, and anus.

Questions to ask your doctor

If your doctor mentions squamous epithelium changes in your report, you might consider asking:

• What caused the changes in my squamous epithelium?

• Do I require additional tests or monitoring due to these changes?

• Is there a risk that these changes could progress to cancer?

• What treatment or lifestyle changes do you recommend to protect my squamous epithelium?

Understanding squamous epithelium can help you stay informed and actively participate in your health care.