Words to Know


A small deposit of calcium in the breast that cannot be felt but can be seen on a mammogram. It is usually caused by aging, an old injury or inflamed tissue, and is usually noncancerous.

magnetic resonance imaging

Also called MRI, NMRI and nuclear magnetic resonance imaging. A procedure in which radio waves and a powerful magnet linked to a computer are used to create detailed pictures of areas inside the body, such as the breast. These pictures can show the difference between normal and diseased tissue. Magnetic resonance imaging creates higher quality images of organs and soft tissue than other scanning techniques, such as computed tomography (CT) or X-ray. It is especially useful for imaging the brain, the spine, the soft tissue of joints and the inside of bones.

magnetic resonance perfusion imaging

Also called perfusion magnetic resonance imaging. A special type of magnetic resonance imaging (MRI) that uses an injected dye in order to see blood flow through tissues.

magnetic resonance spectroscopic imaging

A noninvasive imaging method that provides information about the activity of cells. It is used along with magnetic resonance imaging (MRI), which provides information about the shape and size of the tumor.

mainstream medicine

A system in which medical doctors and other healthcare professionals (such as nurses, pharmacists and therapists) treat symptoms and diseases using medicines, radiation or surgery. Also called allopathic medicine, biomedicine, conventional medicine, orthodox medicine and Western medicine.

maintenance therapy

Treatment that is given to help keep breast cancer from coming back after it has disappeared following initial therapy. It may include treatment with medicines, vaccines or antibodies that kill cancer cells, and it may be given for a long time. Tamoxifen and exemestane (brand name, Aromasin) are two examples of maintenance therapy for preventing breast cancer recurrence.

male breast cancer

Cancer that forms in tissues of the male breast region. Most male breast cancer begins in cells lining the breast ducts. It is very rare and usually affects older men.


A cancerous breast tumor that can invade and destroy nearby tissue, and spread to other parts of the body.


Cancerous. Malignant cells can invade and destroy nearby tissue, and spread to other parts of the body.

malignant pleural effusion

A condition in which cancer causes an abnormal amount of fluid to collect between the thin layers of tissue (pleura), lining the outside of the lung and the wall of the chest cavity. Lung cancer, breast cancer, lymphoma and leukemia cause most malignant pleural effusions.


A condition caused by not getting enough calories or the right amount of key nutrients, such as vitamins and minerals, needed for good health. Malnutrition may occur when there is a lack of nutrients in the diet, or when the body cannot absorb nutrients from food. Cancer and cancer treatment may cause malnutrition.


Having to do with the breast, or breasts.

mammary dysplasia

Also called benign breast disease, fibrocystic breast changes, and fibrocystic breast disease. A common condition marked by benign (noncancerous) changes in breast tissue. These changes may include irregular lumps or cysts, breast discomfort, sensitive nipples and itching. Symptoms may change throughout the menstrual cycle and usually stop after menopause.

mammary gland

Also called breast. A glandular organ located on the chest. The mammary gland is made up of connective tissue, fat and tissue that contains the glands that can make milk.


An X-ray of the breast.


The use of film or a computer to create an X-ray picture that shows the internal anatomy of the breast.


Also called balloon catheter radiation. A system used to deliver internal radiation therapy after breast cancer surgery, in order to remove the cancer. MammoSite targets only the part of the breast where the cancer was found. After an individual has had a lumpectomy to remove the cancer, a small balloon on the end of a catheter (thin tube) is inserted into the empty space left by the surgery. The balloon is then filled with liquid and left in place. Using the catheter, radioactive seeds are put into the balloon twice a day for five days and removed each time. Once treatment has ended, the catheter and balloon are removed. MammoSite is a type of intracavitary brachytherapy and partial breast irradiation therapy (PBRT).


mantle field

The area of the neck, chest and lymph nodes in the armpit exposed to radiation.

MAO inhibitor

Also called monoamine oxidase inhibitor. A type of medicine used to treat depression. It stops the breakdown of certain chemicals in the brain that help improve a person's mood. A MAO inhibitor is a type of antidepressant.