Squamous metaplasia

Squamous metaplasia is a benign (non-cancerous) change that occurs when the normal cells in a tissue or organ are replaced by specialized cells known as squamous cells. This type of change happens as an adaptive response when tissues are repeatedly irritated or inflamed. Squamous metaplasia often occurs in the respiratory tract, urinary tract (especially the bladder), and cervix.

Squamous cells are wide, flat cells that typically form protective barriers on surfaces such as your skin and the lining of your mouth, throat, and cervix. When these cells appear in places they are not usually found, it’s called squamous metaplasia.

Why does squamous metaplasia happen?

Squamous metaplasia usually happens because tissues or organs experience long-term irritation or inflammation. The body responds by replacing sensitive cells with squamous cells, which are tougher and more resistant to injury. Common reasons for this irritation include:

• Exposure to harmful substances or toxins

• Cigarette smoke

• Chronic infections

• Ongoing physical irritation or trauma

In certain areas, such as the cervix, squamous metaplasia is a normal process that naturally happens after puberty due to hormonal changes, particularly increased estrogen levels. This type of squamous metaplasia is considered normal and does not indicate a health problem.

Where in the body does squamous metaplasia occur?

Squamous metaplasia commonly occurs in several parts of the body, including:

• Respiratory tract: Often caused by long-term smoking or chronic irritation, affecting airways such as the bronchi.

• Urinary tract (especially the bladder): Usually results from chronic irritation or inflammation.

• Cervix: Typically, a normal and expected change occurring naturally after puberty due to hormonal stimulation.

Is squamous metaplasia cancerous?

No, squamous metaplasia itself is not cancerous. It is considered a benign, protective adaptation to chronic irritation or inflammation. However, because squamous metaplasia indicates ongoing tissue stress or irritation, your doctor may recommend monitoring or addressing the underlying cause.

How is squamous metaplasia identified?

Squamous metaplasia is typically identified by pathologists examining tissue samples (biopsies) under a microscope. Pathologists look for changes in cell type, noting when normal cells have been replaced by squamous cells. Your doctor might perform a biopsy if they suspect chronic irritation or inflammation to check for metaplastic changes.

Questions to ask your doctor

If your doctor mentions squamous metaplasia, consider asking these questions:

• What caused the squamous metaplasia in my case?

• Is this change something I should be concerned about?

• Do I need additional tests or monitoring?

• Should I take steps to address the underlying cause (like quitting smoking or avoiding irritants)?

Understanding squamous metaplasia helps you stay informed about your health and make better decisions about your care.