October 2, 2023

In pathology, the term benign is used to describe a non-cancerous growth such as a tumour. It can also be used to describe normal tissue. The opposite of benign is malignant.

This picture shows a benign tumour in the breast (between green arrows).
This picture shows a benign tumour in the breast (between green arrows).

Does benign mean normal?

Benign can sometimes mean normal but not always. Pathologists often use this term to say that something is not cancer. However, many non-cancerous things are still not normal. For example, a non-cancerous tumour is benign but it is still an abnormal growth of cells. Importantly, in some areas of the body such as the brain, even non-cancerous tumours can cause significant harm as they grow and damage surrounding tissue.

What is a being tumour?

A benign tumour is a large group of non-cancerous cells that are growing faster than the normal cells around them. Because they are growing faster than normal cells, the tumour cells form a mass that stands out from the surrounding tissue.

Benign tumours can still cause damage by compressing nearby structures, such as other organs, nerves, or blood vessels. However, the cells cannot typically spread to other parts of the body. The movement of tumour cells to another part of the body is called metastasis and this is usually only seen with malignant (cancerous) tumours.

How do pathologists decide if a tumour is benign?

When examining a tumour under a microscope, pathologists will look for the following features to determine if the tumour is benign (non-cancerous) or malignant. (cancerous):

  • The types of cells inside the tumour.
  • The shape, size, and colour of the tumour cells. Very abnormal-looking or atypical cells are more often found in malignant tumours.
  • Tumour cells that are dividing to create new tumour cells. This process is called mitosis. Benign tumours tend to have very few dividing cells although some types are allowed to have many.
  • The relationship between the tumour and the surrounding tissue. Most benign tumours are separated from the surrounding normal tissue. In contrast, malignant (cancerous) tumours tend to invade (spread) into the surrounding healthy tissue.
  • The presence of perineural or lymphovascular invasion. Both of these features are rarely seen in benign tumours.

About this article

Doctors wrote this article to help you read and understand your pathology report. Contact us with any questions about this article or your pathology report. Read this article for a more general introduction to the parts of a typical pathology report.

Other helpful resources

Atlas of Pathology
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