Noncancer (benign) breast lumps can have many causes. Two of the most common causes of benign single breast lumps are cysts and fibroadenomas. Several other conditions can also appear as lumps. These are fat necrosis and sclerosing adenosis. Only your healthcare provider can diagnose your breast lump.
A breast abscess is a pocket of pus that causes swelling and a sore lump in the breast. Other symptoms include fever and tiredness.
A cyst is a fluid-filled sac in the breast tissue. Cysts most often happen in women between ages 35 and 50. They are common in those nearing menopause, but they can develop at any age. The cysts often get larger and become sore just before your period. They may seem to appear overnight. Cysts are rarely cancer (malignant). They may be caused by blocked breast glands.
Cysts can feel either soft or hard. When close to the surface of the breast, cysts can feel like a large blister--smooth on the outside, but fluid-filled on the inside. When they are deep in breast tissue, cysts will feel like hard lumps because they are covered with tissue.
Your healthcare provider may find a cyst during a physical exam. They may confirm the diagnosis with a mammogram or ultrasound. You may also have a fine-needle aspiration. For this, the provider guides a very fine needle into the cyst and draws fluid from it (aspiration). Aspiration also works as the treatment for this condition. Once the fluid is removed, the cyst collapses and goes away. But cysts can return. If they do, they are simply drained again. Cysts are seldom cancer.
Fibroadenomas are solid, smooth, firm, noncancer lumps most often found in women in their 20s and 30s. They are the most common benign lumps in women and can occur at any age. They are increasingly being seen in postmenopausal women who are taking hormone therapy.
The painless lump feels rubbery and moves around freely. You may find one yourself. Fibroadenomas vary in size and can grow anywhere in the breast tissue.
Your healthcare provider may diagnose this type of lump simply by feeling it. But they will want to confirm the diagnosis with a mammogram or ultrasound and fine-needle aspiration. In very young women, the fibroadenoma sometimes is not removed. But because these tumors sometimes get larger with pregnancy and breastfeeding, your provider may suggest having it removed.
Most fibroadenomas don't lead to cancer. But one type of fibroadenoma has been linked to an increased risk for cancer. This is true in women with a family history of the disease.
Fat necrosis is a condition where painless, round, firm lumps caused by damaged and disintegrating fatty tissues form in the breast tissue. Fat necrosis often occurs in women with very large breasts. It also occurs in women who have had a bruise or blow to the breast. This condition may also happen after a lumpectomy and radiation from an earlier cancer lump. In some cases, healthcare providers will watch the lump through several menstrual cycles. They may want to do a mammogram before deciding whether to remove it. These lumps are not cancer and they don't increase your risk for cancer.
These are fluid-filled masses usually caused by a blocked milk duct.
A hematoma is a blood-filled mass caused by injury or a surgical procedure of the breast.
Sclerosing adenosis is extra growth of tissues in the breast's lobules. This often causes breast pain. These changes in the breast tissue are very small, but they may show up on mammograms as calcifications and can make lumps. Usually a biopsy is needed to rule out cancer. This condition can also be mistaken for cancer, so the lumps are usually removed through surgical biopsy.