What Is Metaplasia?

Metaplasia involves cellular changes in tissues. While it is not cancer, it is an abnormal condition. It is considered a risk factor for developing cancer because if cells have changed abnormally once, they are likely to change again. Metaplasia usually occurs in tissues that are consistently exposed to various environmental changes or factors that damage the tissue.

Knowing more about metaplasia can help you talk with a healthcare provider about what to watch for, how to take steps to help prevent metaplasia, and how to possibly reduce your risk of developing cancer in the future.

Definition

Metaplasia is when a differentiated (mature) cell type in a tissue is replaced by another kind of differentiated cell type in the same tissue. The new cell type is usually not found in that tissue, making it abnormal.

Cell changes leading to metaplasia can be caused by environmental stressors like hormones, cigarette smoke, acidic conditions, infectious agents like Helicobacter pylori (H. pylori) or human papillomavirus (HPV), and alcohol consumption, among other things.

When cells are constantly irritated, one response of the cell might be to change, which is when they transform and result in metaplasia.

Metaplasia is a risk factor for cancer. Another transformation after metaplasia is dysplasia, which is considered to be a precancerous condition. However, metaplasia is not cancer.

Types

While metaplasia can occur in many different organs, there are three general categories of metaplasia: squamous metaplasia, intestinal metaplasia, and acinar-ductal metaplasia (ADM). Different kinds of metaplasia can occur in different areas of the body and organs.

Squamous metaplasia can occur in the:

• Lung airway
• Cervix (the canal between the uterus and vagina)
• Mammary glands
• Sebaceous glands (glands in the skin that produce sebum, an oily substance)
• Skin

Intestinal metaplasia can occur in the:

• Esophagus
• Stomach

Acinar-ductal metaplasia can occur in the:

• Pancreas
• Mammary glands
• Salivary glands
  

Causes

Metaplasia often occurs due to exposure to environmental factors that injure or stress the tissue, causing the cells to change. For each kind of metaplasia and the various organs it affects, there may be different causes. This is because the tissues are exposed to different environmental irritants and infections, which produce various effects in the cells.

For squamous metaplasia, causes and the affected organs can include:

• Cigarette smoke: Lung airway
• HPV: Cervix
• Infection: Mammary glands
• Inflammation: Mammary glands, sebaceous glands, skin

Other causes can include a diet high in animal fat, obesity, higher levels of estrogen exposure (like with early menstruation or late menopause), and a family history of endometrial, ovarian, and/or colon cancers.

Causes of intestinal metaplasia can include:

• Acid and/or bile, like in gastroesophageal reflux disease (GERD)
• Obesity
• High salt consumption
• Not enough fruits and vegetables in the diet
• Low vitamin C intake
• H. pylori infection
• Autoimmune gastritis

Acinar-ductal metaplasia is caused by inflammation.

Detection

Screening for and detecting metaplasia is done when a healthcare provider can gain access to the tissue they need to examine. This can be part of regular screening or because of symptoms you are experiencing. It can include endoscopy, biopsy, or Pap smear, depending on where the metaplasia is suspected.

Treatment

Metaplasia is reversible and can be treated. The main factor in helping to reverse it is getting rid of the stimulus that triggered the changes. This may include stopping smoking cigarettes, starting medication for H. pylori like proton pump inhibitors and antibiotics, or getting vaccinated for HPV.

Cervical metaplasia and dysplasia can be monitored and treated after being detected with a Pap smear.

Prevention and risk reduction are a large part of treatment. Talk with your healthcare provider about the best ways to help reduce your risk of metaplasia and future dysplastic changes, as well as any preventive screenings that can monitor cellular changes.

Summary

Metaplasia is an abnormal condition in which healthy mature cells are replaced by a different kind of mature cell that should not be in that tissue. This is often a result of environmental stressors that cause abnormal changes in these cells. The stressors can vary but include acid, bile, cigarette smoke, inflammation, and various infections, including HPV.

While it is a risk factor for cancer because of additional cell changes that can become cancer, metaplasia itself is not cancer. It is reversible and treatable. Talk with a healthcare provider about how to best address your metaplasia so that it can be reversed and future changes can be prevented.