The breast is the tissue that covers the muscles of the chest (lungs). The female breast consists of special tissues that produce milk (mammary tissue) and fatty tissue, and the amount of fat determines the size of the breast.
Basic structure of the breast
The milk-producing part of the breast is divided into 15 to 20 glandular lobes, each containing smaller structures called glandular lobules, which are the site of milk production. Milk is transmitted through a system of tiny ducts called ducts. The ducts interconnect and merge into thicker ducts that eventually open into the nipple. The dark area of skin around the nipple is called the areola.
Connective tissue and ligaments support the breast and give it shape. Nerves provide sensation to the breast. The breast also contains blood vessels, lymphatic vessels, and lymph nodes.
What diseases can occur in the breast?
- Breast cancer: Malignant (cancer) cells that proliferate abnormally in the breast and, if left untreated, can eventually spread to other parts of the body. Although men can also develop breast cancer, the vast majority of breast cancers occur in women. Signs of breast cancer include bloody nipple discharge, skin changes, etc.
- Ductal carcinoma in situ (DCIS): Breast cancer of the ductal cells that has not yet invaded deeper tissue or spread throughout the body. Women diagnosed with DCIS have a high chance of being cured.
- Lobular carcinoma in situ (LCIS): Although it is called a cancer (cancer that occurs in the lobular cells of the lactating breast), it does not infiltrate or spread and is not really a cancer. However, women with LCIS are at increased risk of developing future invasive breast cancer.
- Infiltrating ductal carcinoma: Breast cancer that starts in the ductal cells but then infiltrates deep into the breast and has the potential to spread to other parts of the body (metastases). Invasive ductal carcinoma is the most common type of invasive breast cancer.
- Infiltrating lobular carcinoma: Breast cancer that begins in the lobular cells of the lactating breast but then infiltrates the breast and has the potential to spread to other parts of the body (metastasis). Invasive lobular carcinoma is a rare type of breast cancer.
- Simple breast cyst: The mass is a benign (non-cancerous), fluid-filled sac that usually occurs in women between the ages of 30 and 40. Breast cysts may cause pressure and pain, and the fluid may be drained out of the body.
- Fibroadenoma of the breast: A very common non-cancerous solid tumor of the breast. The typical fibroadenoma forms a painless, mobile mass in the breast and is most common in women aged 20 to 30 years.
- Fibrocystic hyperplasia of the breast: A common breast condition, this noncancerous breast lump may cause discomfort and change in size during the menstrual cycle.
- Plain enlargement: A breast biopsy may show abnormal proliferation of normal, noncancerous ductal cells. Common type hyperplasia may slightly increase a woman’s lifetime risk of developing breast cancer.
- Atypical hyperplasia of the breast: Abnormal cells proliferate in the ducts (ductal atypia) or lobules (glandular lobular atypia) of the breast and are sometimes detected by breast biopsy. Although the disease is not cancerous, women with atypical hyperplasia have a 4- to 5-fold higher risk of developing breast cancer compared to women without breast abnormalities.
- Intraductal papilloma: A non-cancerous, bulky breast mass that grows in the ducts of the breast. An intraductal papilloma may be felt as a lump or cause colorless or bloody fluid to spill from the nipple.
- Mammary adenopathy: Noncancerous growths of the lobules of the breast. On breast x-ray images, breast adenopathy looks like breast cancer, so a biopsy may be needed to rule out breast cancer.
- Lobular tumor: A rare, usually large, fast-growing breast tumor that looks like a fibroadenoma on ultrasound. Lobular tumors may be benign or malignant and are most common in women in their 40s.
- Fat necrosis: A consequence of damage to the fatty tissue of the breast, which may form scar tissue. During a physical exam or on a mammogram, these lumps look like breast cancer.
- Mastitis: An inflammation of the breast that causes redness, pain, heat, and swelling. Nursing mothers are at higher risk of developing mastitis, which is usually caused by an infection.
- Calcifications in the breast: Calcium deposits in the breast are a common finding on mammograms. A certain pattern of calcium deposits suggests a possible cancer and requires further testing or biopsy.
- Gynecomastia: Excessive development of the male breast. Gynecomastia may occur in newborns, boys, and adult males.
What tests might the breast receive?
- Physical examination: By examining the breast and nearby axillary tissue for lumps, skin changes, nipple discharge, or lymph nodes, your doctor can detect abnormalities in the breast. The characteristics of the breast lump (such as size, shape, and texture) are usually noted.
- Breast x-ray: A mammography camera squeezes each breast and takes low-dose x-rays to take pictures. A mammogram is the most common test for early detection or screening of breast cancer.
- Digital mammography: A type of breast x-ray that stores electronic images of the breast in a digital, computer-readable format, as opposed to standard film mammography x-ray, in which the images are generated directly on film.
- Diagnostic Breast X-rays: In addition to routine breast X-rays, additional breast X-rays are sometimes needed to evaluate abnormal breast X-rays findings or breast abnormalities.
- Breast ultrasound: A device placed on the skin reflects high-frequency sound waves through the breast tissue. Such signals are converted into images on a fluoroscopic screen, allowing the doctor to look at structures inside the body. Breast ultrasound can usually determine whether a lump is composed of fluid (cyst) or solid material.
- Magnetic resonance imaging (MRI) of the breast: MRI uses a high-powered magnetic field and a computer to create detailed images of the breast and surrounding structures. Breast MRI can provide information that cannot be found on a breast x-ray and is recommended only in certain circumstances.
- Breast biopsy: A small portion of tissue is removed from an abnormal area of the breast observed on physical exam, breast x-ray, or other imaging studies to check for the presence of cancer cells. Biopsy may be performed by puncture or minor surgery.
- Fine needle aspiration biopsy (FNA) of the breast: The doctor punctures a fine needle into an abnormal area of the breast and withdraws (aspirates) fluid and breast tissue. This is the simplest form of biopsy and is used primarily for easily palpable lumps in the breast.
- Hollow needle aspiration biopsy of the breast: A thicker hollow needle is inserted into the breast lump and the ductal breast tissue (core) is removed. Compared to FNA, hollow-needle aspiration biopsy allows for more breast tissue to be obtained for evaluation.
- Stereotactic breast biopsy: A breast biopsy in which computer-generated images assist the physician in accessing the exact location of the abnormal breast tissue to cut the sample.
- Surgical biopsy: Your doctor may recommend surgical removal of part or all of the breast lump to check for cancer.
- Sentinel lymph node biopsy: A type of biopsy in which the doctor locates and removes the lymph nodes where the primary tumor is most likely to have spread. This type of biopsy helps determine the likelihood of cancer spread.
- Ductography (imaging): A thin plastic tube is inserted into the nipple ducts and contrast is injected into the breast to help the doctor see the ducts. Ductography helps determine the cause of bloody nipple discharge.
- Nipple smear (nipple spill test): A sample of bloody or abnormal fluid leaking from the nipple is examined under a microscope to determine the presence of cancer cells.
- Milk duct lavage: Sterile water is injected into the nipple duct, which is then collected and examined for the presence of cancer cells. This laboratory test is only used in women who are known to be at high risk for breast cancer.
How is breast disease treated?
- Lump removal: A lump in the breast (which may be a breast cancer) and the normal tissue around it are surgically removed. Many early breast cancers are removed by lumpectomy (rather than mastectomy).
- Mastectomy: Surgery to remove the entire breast. A radical mastectomy also removes some chest wall muscle and surrounding lymph nodes.
- Armpit lymph node dissection: Surgery to remove axillary lymph nodes that may be involved in breast cancer. These lymph nodes are the gateway for the cancer to spread to other parts of the body.
- Chemotherapy: Drugs are taken or given intravenously to kill the cancer cells. Chemotherapy helps shrink the tumor, or reduces the risk of the cancer spreading or coming back.
- Radiotherapy: High-energy radiation guided by a machine to the breast, chest wall, and armpit can kill cancer cells that remain after surgery (external radiation). Radiation can also be administered by putting radioactive material into the body (internal radiation).
- Breast reconstruction: When the entire breast or a large amount of breast tissue is removed (such as a mastectomy), the breast can be reconstructed using implants or your own tissue.
- Antibiotics: For mastitis caused by bacteria, antibiotics can often cure the infection.
- Breast augmentation: An artificial implant is surgically placed to increase the size or improve the shape of the breast.
- Mastopexy: Surgical reduction of the breasts. For women, the procedure is often used to relieve neck or back pain caused by overly large breasts. Men may also seek breast reduction for gynecomastia.