What Are Neoplasms and Tumors?

A neoplasm is an abnormal growth of cells in the body. It happens when the body’s normal process of making and replacing cells doesn’t work as it should.

When a neoplasm forms into an abnormal growth, mass, or lesion, it’s called a tumor. Unlike cysts, tumors are usually solid and firm because they are filled with clumps of abnormal cells. Neoplasms don’t always form tumors, but many do, and the two terms are often used interchangeably.

Not all tumors or neoplasms are cancer – they can be benign (not cancer) or malignant (cancer).

Signs of a tumor or neoplasm

Tumors can feel different depending on their size, location, and type. Some can be felt with your hand, while others may be too deep inside the body to find without imaging tests.

A tumor may:

• Feel firm, solid, soft, smooth, or bumpy
• Sometimes cause pain or discomfort
• Often be seen only with x-rays or other imaging tests

Because neoplasms and tumors can be serious, any lump, growth, mass, or lesion you might notice or feel should be evaluated by a doctor.

Benign versus malignant neoplasms and tumors

Not all tumors are cancer. Tumors and neoplasms are considered malignant if their abnormal cells can invade surrounding tissue and spread to other parts of the body. The ability of cancer cells to grow into and spread to other parts of the body is called metastasis.

If the abnormal cells cannot do this, the tumor is benign (not cancer).

Benign neoplasms and tumors

A benign neoplasm or tumor is a noncancerous growth. This means it:

• Does not have cancer cells inside it
• Tends to grow slowly
• Is usually not serious
• Is usually contained to one area
• Cannot spread to other parts of the body

However, benign tumors can sometimes grow quite large or press on organs, nerves, or blood vessels. In these cases, it can be serious and might need to be removed.

Examples of benign neoplasms or tumors:

• Lipoma: A benign growth filled with fat cells. It usually grows just under the skin, such as on the breast.
• Fibroma: A benign growth filled with fibrous tissue, such as scar tissue. These are mostly found in the skin or lungs.
• Adenoma: A benign growth in glands or glandular tissue, usually found in the thyroid or colon. These might be called nodules, such as a thyroid nodule. They can also be called polyps, such as an adenomatous polyp, a common type found in the colon or rectum.
• Hemangioma: A benign cluster of blood vessels that form a reddish or purplish lump. These are commonly found on the skin.
• Meningioma: A benign growth in the layers of the brain and spinal cord. These are often removed because they can cause problems if they put pressure on the brain or spinal cord.

Malignant neoplasms and tumors

A malignant neoplasm or tumor is a cancer. The term “malignant” means cancer cells are present, and the tumor is considered cancerous. Tests are done to know the exact type of cancer cells and to determine the cancer’s stage.

Malignant tumors:

• Tend to grow quickly
• Can invade nearby tissue
• Can spread to other parts of the body
• Are serious and often life-threatening

How serious a malignant neoplasm or tumor is depends on:

• The type of cancer cells found in it
• Where it’s located
• How big it is
• Whether it has spread
• How it’s affecting the person’s health

Examples of malignant neoplasms or tumors include all cancers:

• Hematologic (blood) cancers: These are cancers of the blood cells, including leukemia, lymphoma, and multiple myeloma. These cancers do not always form tumors, but are still considered a type of neoplasm.
• Solid tumor cancers: Cancers of any of the other body organs or tissues. The most common solid tumors are breast, prostate, lung, and colorectal cancers.

Do all neoplasms and tumors need to be removed?

The decision to remove a tumor or neoplasm depends on its size, location, type, and whether it is benign or malignant.

• Benign neoplasms and tumors may need to be removed, or a person may choose to have them removed. In some cases, they can be left alone or watched and rechecked to see if they change or grow in any way.
• Malignant neoplasms and tumors, or cancers, are approached differently. Ideally, doctors want to be able to completely get rid of a malignancy. In some cases, all of it can be removed with surgery. In other cases, only part of the cancer can be removed. And for some, the cancer can’t be removed and is considered to be inoperable.

A tumor or neoplasm might not be removed if it:

• Is very large
• Is in a hard-to-reach area
• Is in a sensitive place next to important organs, blood vessels, or nerves, and if removing the cancer could cause damage to the surrounding tissues and structures
• Has its own blood supply and removing it might cause excessive bleeding
• Is a very aggressive type of cancer or the cancer has already spread
• Another treatment would be more effective