Why do breast lumps get bigger and smaller?

Breast lumps that often get bigger and smaller are breast cysts. Breast cysts are fluid collections in the ducts of the breasts. Without an ultrasound, you cannot be sure that a breast lump is a cyst. An ultrasound will determine if the breast lump is a fluid-filled sac or a solid breast mass. Cysts are common in the breast, and often grow and shrink in size.

Dr. Mehmet Oz, MD
Cardiologist (Heart Specialist)

So-called normal breast lumps due to fibrocystic changes get bigger and smaller as hormone levels change inside your body. Lumps that are not normal slowly get larger. Watch Dr. Oz talk more about the different kinds of breast lumps.

When you consider why a breast lump might get bigger or smaller, it's important to realize that not all breast lumps are made up of the same stuff.

Some breast lumps are made of normal breast tissue that has just gotten a little more prominent and so stands out as a lump. Other lumps are cysts, or fluid filled structures within the breast tissue. Occasionally, fluid filled pockets in the breast can be due to an infection called an abscess. Still other lumps are composed of solid tissue that is not normal breast tissue. Most of these solid lumps are not cancer, but some can be. So, when considering the question, "why do some breast lumps get bigger and smaller?" the answer depends heavily on what the lump is. So, it is very important to report any breast lumps to your primary care provider to have a thorough evaluation of these lumps.

Most every benign lump has the potential to grow or shrink. Sometimes these changes are related to the ebb and flow of estrogen and progesterone that happens throughout the menstrual cycle. Even solid lumps that are benign can grow for a time and then shrink away. But not all will, so it's important that you don't assume a lump is harmless. Instead, show the area to your doctor and let him/her complete a thorough evaluation of the lump.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.