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Finding out that you have a tumor can be frightening. However, not every tumor is cancerous. Tumors can generally be classified as benign or malignant, and understanding the difference can help make a diagnosis easier to understand.

What Is a Tumor?

A tumor is an abnormal mass of cells that develops when cells grow or divide more than they should, or when they fail to die when they normally would.

Tumors can develop in many parts of the body. Some are harmless and never cause serious problems, while others can affect nearby organs or become life-threatening.

Importantly, not every abnormal growth is a tumor. Some cancers, such as leukemia, usually do not form solid tumors.

What Is a Benign Tumor?

A benign tumor is a noncancerous growth. It does not invade nearby tissues or spread to distant parts of the body.

Benign tumors often grow slowly and may remain in one area. Some may never cause symptoms and may only be discovered during a routine examination or imaging test.

However, "benign" does not always mean that a tumor can be ignored. A benign tumor can sometimes cause problems if it becomes large or presses against important organs, nerves, or blood vessels.

For example, a benign tumor in the brain can cause serious symptoms because there is limited space inside the skull.

What Is a Malignant Tumor?

A malignant tumor is cancerous. Malignant cells can grow uncontrollably and invade surrounding tissues.

Some malignant cells can also break away from the original tumor and travel through the blood or lymphatic system to other parts of the body. This process is called metastasis.

When cancer spreads, it can form new tumors in distant organs. The new tumors are still considered the same type of cancer as the original cancer.

For example, if breast cancer spreads to the lungs, it is still breast cancer that has spread to the lungs rather than lung cancer.

How Do Benign and Malignant Tumors Differ?

Several characteristics can help doctors distinguish between benign and malignant tumors.

Growth

Benign tumors often grow slowly, although some can grow more quickly. Malignant tumors may grow more rapidly and can continue growing into surrounding tissues.

Location

Benign tumors usually remain in their original location. Malignant tumors can invade nearby tissues and may spread to distant organs.

Cell Appearance

Under a microscope, benign tumor cells often look more similar to normal cells. Malignant cells may look abnormal and have changes in their size, shape, and organization.

Ability to Spread

Benign tumors generally do not spread to other parts of the body. Malignant tumors can spread through the bloodstream or lymphatic system.

Recurrence

Some benign tumors can return after removal, but malignant tumors have a greater risk of returning, particularly if cancer cells remain after treatment.

What Causes Tumors to Develop?

Tumors develop because of changes in the DNA of cells. These changes can affect genes responsible for controlling cell growth and division.

Several factors may contribute to these genetic changes, including:

• Aging

• Tobacco use

• Radiation exposure

• Certain infections

• Environmental exposures

• Inherited genetic changes

• Random changes that occur as cells divide

Sometimes, there is no clear reason why a particular tumor develops.

How Are Tumors Diagnosed?

Doctors may discover a tumor during a physical examination or through an imaging test such as an ultrasound, CT scan, or MRI.

However, imaging alone may not always determine whether a tumor is benign or malignant.

A biopsy may be needed. During a biopsy, a sample of tissue is removed and examined under a microscope by a specialist. The results can provide important information about the cells and help determine whether the growth is cancerous.

Additional tests may be performed to learn more about the tumor and guide treatment.

How Are Benign Tumors Treated?

Not every benign tumor requires treatment. If a tumor is small and does not cause symptoms, a healthcare provider may recommend monitoring it with regular checkups or imaging.

If a benign tumor causes pain, affects organ function, grows significantly, or creates another health concern, surgery may be recommended to remove it.

Treatment depends on the tumor's location, size, type, and effects on the body.

How Are Malignant Tumors Treated?

Treatment for malignant tumors depends on the type and stage of cancer, where it started, whether it has spread, and the person's overall health.

Treatment may include:

• Surgery

• Chemotherapy

• Radiation therapy

• Immunotherapy

• Targeted therapy

• Hormone therapy

Doctors may use one treatment or combine several approaches to control or eliminate the cancer.

FAQs

Are all tumors cancerous?

No. Tumors can be benign or malignant. Benign tumors are not cancerous, while malignant tumors are cancerous.

Can a benign tumor become malignant?

Most benign tumors do not become cancerous. However, certain types of abnormal growths may have a higher risk of developing into cancer, so appropriate medical follow-up is important.

Can benign tumors cause health problems?

Yes. A benign tumor can cause problems if it grows large or presses against an organ, nerve, blood vessel, or other important structure.

How do doctors know if a tumor is malignant?

Doctors may use imaging tests and other evaluations, but a biopsy is often needed to examine the tumor cells and determine whether they are cancerous.

Can malignant tumors spread to other parts of the body?

Yes. Malignant cancer cells can spread through the blood or lymphatic system. This process is called metastasis.

Conclusion

The main difference between benign and malignant tumors is how they behave. Benign tumors are noncancerous and generally remain in one location, while malignant tumors are cancerous and can invade nearby tissues or spread to distant parts of the body.

A tumor diagnosis does not automatically mean cancer. Doctors use examinations, imaging tests, biopsies, and other evaluations to determine the nature of a growth.