Dysplasia

Dysplasia is an abnormal growth of cells within a tissue or organ. In most body parts, it is considered a precancerous change. Pathologists use this term when cells appear unusual or disorganized under the microscope. Unlike cancerous cells, the cells in dysplasia are still confined to their original location. Dysplasia is associated with an increased risk of developing cancer over time.

Is dysplasia always a precancerous change?

Pathologists typically use the term dysplasia to describe a precancerous change; however, there are instances when dysplasia is not associated with an increased risk of cancer. For example, fibrous dysplasia is a condition where abnormal fibrous tissue develops within bones, causing structural changes but not considered precancerous. Similarly, other conditions affecting bones and cartilage, such as skeletal dysplasias, involve abnormal development but do not carry an increased risk of progressing to cancer.

Does dysplasia mean cancer?

No, dysplasia does not mean cancer. It represents abnormal cells that have the potential to develop into cancer over time but have not yet acquired all the features necessary to invade tissues or spread to other parts of the body. Dysplasia is therefore viewed as a warning sign that requires careful monitoring or treatment to prevent the progression to cancer.

How often does dysplasia turn into cancer?

The likelihood of dysplasia becoming cancer varies significantly based on its location, grade, and underlying cause. In general, high grade (severe) dysplasia carries a greater risk of progressing to cancer compared to low grade (mild) dysplasia. For example, high grade cervical dysplasia (also known as high grade squamous intraepithelial lesion or HSIL) is more likely to become cervical cancer than low grade cervical dysplasia (also known as low grade squamous intraepithelial lesion or LSIL). However, not all dysplasia will progress, and some cases may remain stable or resolve completely.

Can dysplasia go away on its own?

Yes, in some cases, dysplasia can resolve spontaneously, especially if the cause is eliminated or controlled. For instance, low grade dysplasia associated with human papillomavirus (HPV) infection may clear when the immune system effectively fights off the virus. However, high grade dysplasia usually requires medical intervention because it rarely resolves without treatment.

What causes dysplasia?

Dysplasia results from genetic changes in cells triggered by various factors.

Common causes include:

• Chronic inflammation, such as from long-term irritation or inflammatory diseases.
• Prolonged hormonal stimulation, such as exposure to estrogen.
• Viral infections, notably HPV.
• Exposure to harmful substances, such as tobacco smoke or ultraviolet radiation.

These genetic alterations disrupt normal cell growth, causing cells to look and behave abnormally.

How do pathologists grade dysplasia?

Pathologists grade dysplasia based on how abnormal the cells appear under a microscope. Grading helps doctors determine how likely the dysplasia is to progress to cancer and guides treatment decisions.

The grading typically involves:

• Low grade dysplasia (mild): The cells are slightly abnormal. The risk of progression to cancer is lower, and monitoring may be recommended.
• High grade dysplasia (moderate to severe): The cells appear highly abnormal, closely resembling cancer cells. This grade carries a higher risk of becoming cancerous and often requires treatment such as surgical removal of the abnormal cells.

What is the difference between dysplasia and metaplasia?

Dysplasia and metaplasia are both terms describing abnormal cell changes, but they differ significantly in their microscopic appearance, causes, and risk of developing cancer over time.

• Dysplasia refers to abnormal growth with cells appearing disorganized and abnormal in structure. Dysplasia is precancerous and can progress to cancer.
• Metaplasia describes a situation where one type of normal cell is replaced by a different kind of normal cell, typically due to chronic irritation or inflammation. While metaplasia is not precancerous, it creates an environment where dysplasia may develop.

Understanding these distinctions helps guide monitoring and treatment strategies to manage risk and maintain health.