A breast mass is a growth of tissue within the breast that may be cancerous or benign. Masses may be difficult to detect, as a woman's breast consists of 15 to 20 sections, called lobes, as described by the National Cancer Institute. Each lobe is made up of smaller sections called lobules. Inside the lobules are glands responsible for producing milk and ducts that carry the milk to the nipple. The space between all of the lobules and ducts are filled fat tissue and fibrous connective tissue. There are several different types of breast masses that can occur anywhere in the breast.
Fibroadenoma
Fibroadenomas, a non-cancerous type of breast mass, are the most common type of breast lump in premenopausal women, according to the doctors at the Mayo Clinic. These lumps are solid and well-defined lumps that can feel firm, smooth, rubbery or hard. Fibroadenomas usually move easily when pushed on and are painless.
Fibroadenomas can consist of both the gland tissue found within a breast and the connective tissue. The exact cause is not known, but as this type of breast mass affects women during their reproductive years, hormones may contribute to their formation.
Fibrocystic Breasts
Approximately 50 percent of all women undergo fibrocystic changes in their breasts at some point during their life, as reported by the American Cancer Society. Doctors used to refer to it as fibrocystic breast disease, but now realize that these changes within the breast are both common and benign.
Fibrocystic changes occur in both the gland tissue and the connective tissue of breasts. These changes create masses of varying size that feel ropy, lumpy or bumpy. Fibrocystic breasts have areas that feel thicker than others and may feel tender or even painful. A non-bloody discharge from the nipples may occur in those with fibrocystic breasts, according to the Mayo Clinic.
Mastitis
Mastitis is an infection of the breast that most commonly occurs in women who are breastfeeding. Mastitis is caused by bacteria gaining entry into the breast through a break in the skin or through the nipple. Mastitis causes swelling of breast tissue that feels like a mass. Other symptoms include fever, chills, breast tenderness and breasts that are hot to touch or red.
Breast Cancer
Breast cancer is the formation of a mass due to the abnormal and uncontrollable growth of cells. The cancer may form in either the ducts or the lobules, creating masses. Breast cancer cells can break away from the mass and travel to affect other tissues in the body, as described by the National Cancer Institute.
