There are different causes for lumps in the breast. Not all of them are cancer.
Cysts: Harmless growths in the breast tissue. They tend to occur with hormonal changes, such as with the start of a menstrual period. Cysts are usually filled with fluid that can be drained with a needle. It is possible for cysts to reoccur after the fluid has been drained.
Fibrosis: A thickening of the tissue within the breast. It is usually harmless.
Benign tumors: Solid growths that are not cancerous or dangerous. They can be uncomfortable, and they can sometimes cause leakage from the nipples, depending on their location. The only way to determine if a tumor is cancerous or benign is by looking at the cells that make up the tumor under a microscope.
It is important to see a doctor to find out which type of lump is present in the breast. Early treatment can then be started if needed.
A doctor will likely order image testing to see the lump and surrounding tissue. Examples include mammogram, ultrasound, or MRI. Someone at low risk for breast cancer may be asked to monitor the lump and to return periodically to check on it.
Sometimes the doctor will want to do a biopsy. This involves removing a small amount of the lump, in order to diagnose the cause. The only way to definitively diagnose breast cancer or other conditions is to perform a biopsy.
There are several different types of biopsies:
Fine needle aspiration biopsy: A small needle is inserted into the lump and a few cells are removed to be studied.
Core needle biopsy: A slightly larger needle is used to remove three to six small cylinders of tissue from the abnormal breast tissue. The samples are then looked at under a microscope.
Surgical biopsy: A surgeon makes a cut into the breast to remove either a small amount of the abnormal tissue or the entire lump. Removing the entire lump is known as an excisional biopsy.
An excisional biopsy is also known as a breast lump removal or a lumpectomy. This procedure removes only the abnormal tissue and a small amount of surrounding tissue from the breast. It leaves the rest of the breast intact.