Definition of Benign in Medicine

What Does it Mean if a Condition is Benign?

cells under a magnifying glass used to differentiate benign and malignant tumors
What does the term benign mean in medicine, and what is a benign tumor?. Photo©vitanovski

Definition: Benign

In medicine, the word benign refers to a condition that is not dangerous to health. While most people are most familiar with its use to describe a condition that is not cancerous, benign is used to describe many health conditions that could be either non-threatening (benign), or of more concern.

An example of a non-tumor use of the word benign would be to say that the course of a disease is "benign." In other words, the disease was unlikely to be life-threatening.

Sometimes it is used in reference to high blood pressure, where the use of the phrase "malignant hypertension" means blood pressure that is extremely high and could cause a stroke, versus "benign hypertension" which could cause problems down the line, but is not immediately life-threatening.

What are Benign Tumors?

Benign tumors result from an overgrowth of normal cells. Benign tumors are simply tumors that are not cancerous.There are many differences between benign and malignant tumors, but there are also some similarities. There are also many differences between cancer cells and the normal cells that make up these tumors.

Characteristics of Benign Tumors

Some of the characteristics of benign tumors may surprise you:

  • Benign tumors may grow quite large.
  • Benign tumors may recur - The difference is that when these tumors recur, they recur in the same location in which they were originally found, and do not recur in distant tissues and organs.
  • Benign tumors can be dangerous - These tumors may press on vital organs, and when they grow in an enclosed space like the brain, can cause damage that is life-threatening.
  • Benign tumors, however, do not metastasize. They do not spread to lymph nodes and distant regions of the body.

Treatment of Benign Tumors

As with cancerous tumors, benign tumors may be treated in a number of ways.

  • Surgery - Most often the treatment of choice for benign tumors is surgical removal.  
  • Radiation - Some benign tumors are treated with radiation therapy. This is more likely to occur if surgery to remove the tumor is difficult because of the location of the tumor, for example, with a benign brain tumor.
  • Medication - Some benign tumors may be treated with medication to reduce the size. An example would be using the medication bromocriptine to decrease the size of a pituitary microadenoma.
  • Nothing - Many benign tumors, for example, lipomas, can simply be left alone.

Can Benign Tumors Become Cancerous?

The answer to the question "can benign tumors become cancerous" depends upon the type of a benign tumor; sometimes the answer is yes, and sometimes it is no. An example can be found in looking at two benign tumors of the colon known as polyps. Hyperplastic polyps are benign tumors that are very unlikely to ever become cancerous. Adenomatous polyps, in contrast, have a tendency to become malignant, and it's estimated that one in ten of these do transform. This is the reason that colonoscopy exams can be used for cancer screening in two ways; they can detect cancers in the early stages, but also allow doctors to remove adenomatous polyps before they can become cancerous.

Examples of Benign Tumors

A few examples of benign tumors found by locations in the body include:

  • Lipomas (fatty tumors noted just under the skin,)
  • Hemangiomas (tumors of blood vessels that are red and blue and often referred to as birthmarks.)
  • Fibroadenomas (benign tumors found commonly in the breast.)
  • Schwannoma and neurofibroma (benign tumors of nerve tissue.)
  • Papillomas (found in the cervix and elsewhere.)
  • Hamartomas (hamartomas are the most common type of benign lung tumor.)
  • Osteoma (benign tumor found in bone.)
  • Adenoma (found in the liver and elsewhere.)

Naming of Benign vs Malignant Tumors

The name of a tumor may often help you understand if that tumor is benign or malignant.

Malignant tumors often have the word "sarcoma" or "carcinoma" after the type of cells, based on the type of tissue in which the cancer arose.

An example would be in a type of bone tumor. An osteoma refers to a benign bone tumor in this category, whereas its malignant counterpart would be called an osteosarcoma.

Pronunciation: bee-nine

Examples: Susan was relieved that the biopsy of her lung mass was benign.


National Cancer Institute. SEER Training Modules. Tumor List. Accessed 01/27/16.

National Institute of Health. MedlinePlus. Benign Tumors. Updated 07/07/16.

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