Benign vs. Malignant (compare)
Both terms describe the same kind of finding — an abnormal growth of tissue — and differ in how the cells behave.
| Benign | Malignant | |
|---|---|---|
| What it is | A tumor (abnormal growth of body tissue) that is noncancerous (MedlinePlus, NIH, 2024-07-15) | A tumor that is cancerous, with cells able to spread to other sites (metastasize) or invade and destroy nearby tissue (MedlinePlus, NIH, 2024-08-21) |
| How the cells behave | Cells grow more than they should but stay within the growth itself | Cells tend to grow fast and in an uncontrolled way and do not die off normally, because of changes in their genetic makeup (MedlinePlus, NIH, 2024-08-21) |
| What causes it | Tumors form when cells divide and grow excessively and the balance of cell growth and cell death is disturbed (MedlinePlus, NIH, 2024-07-15) | The same imbalance, with risk raised by tobacco — which causes more cancer deaths than any other environmental substance — plus chemicals and toxins, excess alcohol, excessive sunlight, genetic problems, obesity, radiation and certain viruses (MedlinePlus, NIH, 2024-07-15) |
| How it's typically diagnosed | A piece of tissue is removed and examined under a microscope (a biopsy) by a pathologist, a doctor who studies cells and tissue (National Cancer Institute, 2023-01-17); CT or MRI scans show location and extent (MedlinePlus, NIH, 2024-07-15) | The same biopsy and imaging; PET scans are used to find certain tumor types, and blood or urine tests may be added (MedlinePlus, NIH, 2024-07-15; National Cancer Institute, 2023-01-17) |
| How samples are taken | By needle, or through an endoscopy such as a colonoscopy (National Cancer Institute, 2023-01-17) | By the same needle or endoscopic methods |
| How it's typically treated | Treatment varies by tumor type and location; it may not be needed if the growth is in a "safe" area where it will not cause symptoms or affect organ function, and removal may still be chosen for symptoms, cosmetic reasons, or pressure on brain tissue (MedlinePlus, NIH, 2024-07-15) | Treatment also varies by type and location, and may include chemotherapy, radiation, surgery, targeted cancer therapy, immunotherapy and other options (MedlinePlus, NIH, 2024-07-15) |
| What follow-up looks like | Monitoring or repeat imaging, on a schedule your doctor sets; outlook is generally very good, though a benign tumor can sometimes cause severe problems (MedlinePlus, NIH, 2024-07-15) | Monitoring after treatment, because cells resistant to chemotherapy or radiation may return after all detectable traces were removed or destroyed (MedlinePlus, NIH, 2024-08-21) |
Which tests you get, how often, and what counts as an abnormal result vary by your age, your other conditions, the lab running the test, and which edition of a professional guideline your clinic follows. Ask which one is being used for you.
Get same-day medical contact, or emergency care, for a growth or lump with sudden severe pain, heavy or uncontrolled bleeding, trouble breathing or swallowing, a sudden severe headache with vomiting, or new weakness, numbness or trouble speaking.
