Benign and Malignant Breast Lumps

See your healthcare provider if you have any breast changes

During a breast self-exam (BSE), you may notice lumps or differences in the texture and appearance of your breasts. While this may be worrisome, only 3% to 6% of these changes are due to breast cancer.

Several types of breast lumps are benign (noncancerous) but can mimic breast cancer. Although tests such as mammograms, ultrasound, and magnetic resonance imaging (MRI) can offer clues to whether a lump is cancerous, the only way to know for sure is to have the lump biopsied.

This article will review the differences between noncancerous and cancerous breast lumps.

what a cancerous breast lump feels like

Verywell / Brianna Gilmartin

Benign Breast Changes

Benign breast changes can occur due to hormonal fluctuations and age. Although most lumps are not cancerous, they can be painful and lead to infections. Any changes in your breast should be reported to your healthcare provider.

Breast Cysts

A breast cyst is a benign, fluid-filled sac in the breast tissue. About 50% of women age 30 and over develop breast cysts, also called fibrocystic disease. In some cases, these cysts can be painful and require aspiration (fluid removal) if the mass is large and is causing problems.

Breast cysts are caused by hormonal imbalances such as increased estrogen levels and decreased progesterone. Sometimes breast cysts improve after menopause. Although usually benign, complex cysts do have a risk of becoming malignant (cancerous).

Performing a monthly BSE allows you to become familiar with your breasts so you can report any changes to your healthcare provider quickly.

Breast Fibroadenomas

Breast fibroadenomas are benign tumors that consist of glandular and connective tissue. They typically affect women in their 20s and 30s, but they can occur at any age.

A fibroadenoma typically feels round and firm and moves beneath the skin during a BSE. Fibroadenomas are often located near the surface of the breast. However, some may be too small to feel and are detected incidentally on a mammogram. 

Although cancer risk is extremely rare with fibroadenomas, a biopsy may be warranted if the mass is large enough. Lumpectomy, radiofrequency ablation, and several other fibroadenoma treatments are available to remove the benign tumor.

Adenosis

Adenosis is a benign condition characterized by enlargement in the breast's lobules. A breast lobule is a gland that makes milk. Adenosis can produce a lump that feels like a cyst or a tumor. In addition, it can have the appearance of calcifications on a mammogram. Calcifications can signify breast cancer, so a biopsy is required to diagnose adenosis.

Mastitis 

Mastitis is an infection of the breast experienced by many women who breastfeed. It is often accompanied by redness, swelling, and pain. In addition to home remedies, mastitis is treated with antibiotics. Sometimes it may be difficult to distinguish between mastitis and inflammatory breast cancer since symptoms of both include breast redness, tenderness, and rash.

Duct Ectasia

Mammary duct ectasia is a benign condition in which the milk ducts become clogged and swollen, often causing a grayish discharge from the nipple. It may cause a small lump just under your nipple or cause the nipple to be retracted inward. It most commonly occurs around the age of menopause. Mammary duct ectasia usually resolves independently or can be treated with antibiotics.

Fat Necrosis

Fat necrosis may occur when the breasts are damaged by surgery, radiotherapy, or trauma. Fat necrosis causes superficial (below the skin), hard, round lumps with skin retraction. This condition mimics breast cancer on imaging tests and requires a biopsy for diagnosis. Seatbelt injuries, breast surgeries, and being on blood thinners are common causes of fat necrosis.

Breast Oil Cysts

Breast oil cysts develop as a result of fat necrosis. As fat cells die, their contents are released, forming a cyst filled with oil. Although breast oil cysts usually resolve with time, they can be removed if they become uncomfortable.

Other Benign Lumps

Other benign lumps include breast hematomas, hemangiomas, adenomyoeptheliomas, and neurofibromas. Although these lumps are considered noncancerous, it's important to continue monthly BSEs and report new breast changes to your healthcare provider.

Benign Breast Lumps and Future Cancer Risk

According to a 2019 study in the International Journal of Cancer, women with benign breast disease (BBD) have an increased risk of developing breast cancer in the future. In addition, women with BBD, a family history of breast cancer, and genetic mutations have an even greater risk of developing breast cancer.

Pre-Cancerous Breast Lumps

Several benign breast lumps are strongly associated with increased cancer risk. Others are pre-cancerous growths that can transform into cancer cells later. While most benign breast lumps resolve independently or are removed for comfort, pre-cancerous lumps must be excised (surgically removed) entirely.

Intraductal Papillomas

Intraductal papillomas are tumors that begin in the milk ducts of the nipple and often cause nipple discharge. While these tumors are typically benign, they may be associated with an increased risk of cancer, particularly if there are regions of atypical hyperplasia (abnormal cells). Surgical removal of the papilloma and the affected duct are often recommended.

Radial Scars

Contrary to what the name suggests, radial scars are not actual scars, but the term describes how they look under a microscope. This condition often affects both breasts and is diagnosed with a biopsy.

Radical scars are an uncommon breast lesion that puts women at a slightly higher risk for developing breast cancer. They do not usually cause a palpable (feelable) lump but may appear as a spiky mass on a mammogram. Depending on how the tumor looks under the microscope, some radial scars need to be removed.

Ductal or Lobular Hyperplasia

Atypical lobular hyperplasia and atypical ductal hyperplasia are considered precancerous conditions. Atypical describes cells that look abnormal under a microscope, and hyperplasia means there is an overgrowth of cells. Breast tumors that have these characteristics are more likely to turn into cancer; therefore, close monitoring or surgical excision is required to treat these conditions.

In Situ Tumors (DCIS and LCIS)

Ductal carcinoma in situ (DCIS) is considered pre-invasive breast cancer or stage 0. When cancerous cells line the ducts of a breast lobule but do not invade the breast tissue, it's called DCIS. However, if the cancer cells spread out to the surrounding tissue, it is considered invasive breast cancer. Several breast surgery options are available to treat DCIS.

On the other hand, lobular carcinoma in situ (LCIS) occurs when cancer cells are found in the lining of the breast lobule. Although LCIS is not considered a cancer diagnosis, people with LCIS have nine to 10 times the risk of developing invasive carcinoma compared to the general population. Even with those odds, however, not all LCIS is treated surgically. Instead, some healthcare providers recommend regular breast screening and follow-up visits.

Phyllodes Tumors 

Phyllodes breast tumors account for less than 1% of breast tumors. Approximately 60% to 75% of those cases are categorized as benign. Although most phyllodes tumors are noncancerous, the standard treatment is to surgically remove them.

Most breast cancers start in epithelial cells. In contrast, phyllodes tumors begin in mesenchymal cells (connective tissue cells), and the tumors are defined as sarcomas.

Breast Cancer

Breast cancer is a malignancy made of abnormal breast tissue cells. If breast cancer goes untreated it can spread to the lymph nodes, organs, and bones.

Malignant breast tumors include:

Location and Composition

Breast cancer can occur anywhere in the breast, but the most common location is the upper-outer section of the breast. It can be located near the surface or deeper inside the breast, close to the chest wall. It can also occur in the armpit area, where there is more breast tissue (a.k.a. the "tail" of the breast).

A breast cancer lump is typically fixed in one spot and doesn't move around during a BSE. The lump may have an irregular shape and be hard like a pebble or a rock. Be sure to have any new lump evaluated by your healthcare provider.

Diagnosis and Treatment

A clinical breast exam, mammogram, and other imaging tests can offer clues as to whether a breast lump is cancerous or not. However, a needle or excisional biopsy is the only way to distinguish between cancerous and noncancerous conditions.

A pathologist looks at the biopsied tissue under a microscope and determines what type of breast cancer it is and how aggressive it may be. There are many variations in breast cancer that make the disease unique to each person who is diagnosed with it.

Since it can take up to 72 hours to get biopsy results, the wait can be stressful. Maintaining your daily routine and focusing on health can be helpful during this time.

Metastatic Cancer

On rare occasions, other types of cancers can metastasize (spread) to organs and tissues, including the breasts, causing new lumps. A biopsy will determine which type of cancer is responsible for the breast tumors.

If the diagnosis is breast cancer, treatment depends on the stage at diagnosis and what mutations are causing the cancer to grow. In addition to surgery, treatments may include chemotherapy, hormonal therapy, radiation therapy, or targeted therapies.

Summary

Although breast lumps are common, they can also be unnerving. Rest assured that most are not cancerous. Benign breast masses may or may not put you at a higher risk for breast cancer in the future. Other lumps are precancerous, meaning they could turn into cancer later. Performing monthly BSEs allows you to become familiar with your breast's appearance, shape, and size so you can recognize new lumps early.

A Word From Verywell

Often women will not report new lumps or bumps out of fear. However, the sooner you are evaluated by your healthcare provider, the sooner you can find an answer to what's causing your breasts to change. Breast cancer is curable if caught early, so it's essential to undergo recommended breast cancer screening and attend regular follow-ups with your healthcare provider.

Frequently Asked Questions

  • How quickly does a breast cancer tumor grow?

    It depends. The growth rate of a breast cancer tumor varies based on several factors, such as the type of breast cancer, tumor characteristics, and the genetics of the cancer. More aggressive breast cancer types like hormone receptor-negative and inflammatory breast cancer can grow and spread quickly.

  • What should I do if I find a lump while breastfeeding?

    Breast changes while nursing can be expected and may include a clogged milk duct or mastitis. However, it is important to report any new lump to your healthcare provider since some of these benign conditions still require treatment with antibiotics.

  • What does breast cancer look like on a mammogram?

    Mammograms have a black background with white and gray coloring to show breast tissue. Cancerous tumors typically show as a very defined, bright white spot, though dense breast tissue can make them harder to see. A doctor specializing in radiology, called a radiologist, is an expert in reading mammograms and other imaging tests.

  • What does a breast lump feel like?

    A cancerous breast lump usually feels hard like a rock and is immobile when you push on it. The lump may also be irregularly shaped. A non-cancerous breast lump may be smooth, soft, and is moveable from side to side.

  • Do breast cancer lumps hurt?

    Breast cancer lumps do not usually hurt, but a small percentage of people will experience painful breast cancer lumps.

Originally written by
Pam Stephan
Pam Stephan is a breast cancer survivor.
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