Different types of lumps can develop in the left, right, or both breasts. These may be due to noncancerous tumors or cysts, or infections. If a person notices any changes in sensation or appearance of the breast, it is essential to consult a doctor to rule out any malignant, or cancerous, lumps.

The majority of breast lumps are benign, or noncancerous. A breast lump can appear anywhere in the breast tissue, but most commonly in the following areas:

  • near the surface of the skin
  • deeper inside the breast tissue
  • closer to the armpit area
  • on the side of the breast

Sometimes, a lump in the breast can signify cancer, so a person should consult a doctor regarding any changes or lumps they find in their breast.

This article discusses what to do if a person finds a lump, the causes, signs to look out for, lumps in males vs. females, and when to see a doctor for a diagnosis.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

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Breast tissue is naturally lumpy, and its textures change with hormones and aging processes. A person should compare the size, appearance, and texture of both breasts. Evenly dispersed lumps in both breasts usually indicate healthy breast tissue.

If a person discovers a new lump in one of their breasts, they can consult a doctor to discuss any concerns, the characteristics of the lump, and any other breast changes.

Lumps that differ from the surrounding breast tissue may suggest a tumor. This could be cancerous, noncancerous, or another breast condition.

Learn how to examine your breasts here.

There are various causes of breast lumps. Some of the most common causes include:

Fibroadenoma is the most common type of noncancerous tumor that affects the breast. Fibroadenomas are most common among females aged 20–30, but females of any age can have them.

A fibroadenoma is a tumor made up of glandular and connective tissues. It feels like a small, round marble in the breast and is not tender to the touch.

Signs or symptoms of a fibroadenoma include:

  • clear-cut borders
  • moveable under the skin
  • firm or rubbery to the touch

The lumps tend to measure around 2.5 centimeters (cm) in diameter. Some are too small to feel, but they will appear on mammograms and ultrasounds. A lump may also grow to 5 cm, and doctors refer to this as a giant fibroadenoma.

For females, the size of the lump may vary due to the presence of higher estrogen levels during pregnancy or hormonal therapy. However, fibroadenomas may shrink during menopause.

Some people will have more than one fibroadenoma. According to the American Cancer Society (ACS), having a fibroadenoma can slightly increase a person’s risk of breast cancer.

Not all fibroadenomas require treatment. Some will shrink or even disappear on their own. A doctor will usually recommend removing the fibroadenoma if it grows or causes changes within the breast.

Learn more about menopause and sore breasts here.

Breast cysts are round sacs of fluid that can develop in breast tissue. Cysts account for about 25% of masses in the breast. They are benign and do not affect someone’s risk of breast cancer.

Breast cysts mainly affect females in their 40s, but people can develop them at any age.

Symptoms include:

  • one or more round, movable masses under the breast skin
  • lumps with a smooth, rubbery texture
  • lumps that are tender or painful to the touch

Doctors use ultrasound scans to diagnose breast cysts. If the ultrasound identifies that the cyst appears solid or has solid areas, the doctor may recommend a breast biopsy to rule out breast cancer.

Cysts that contain only fluid do not need treatment unless they are very large or cause discomfort.

Learn the difference between a cyst and a tumor here.

Fibrocystic breast changes occur when hormonal changes during menstruation cause lumpiness in one or both breasts.

Fibrocystic breast changes happen over time and over repeated menstrual cycles. They can cause some discomfort, but they do not increase the risk of breast cancer.

Other symptoms of fibrocystic breast changes include:

  • tenderness or pain in the breast
  • pain under the arms
  • green or brown nipple discharge

Although fibrocystic breast changes tend to be harmless, they can make detecting breast cancer through breast self-examinations more difficult. This is why people need to have regular breast cancer screenings.

Fibrocystic breast changes do not usually require medical treatment. Taking over-the-counter (OTC) pain relievers and using warm compresses can help relieve uncomfortable or painful symptoms.

Learn more about other reasons for sore, lumpy breasts after a period here.

An intraductal papilloma is a noncancerous tumor that develops in the milk ducts. These growths are a common cause of nipple discharge.

People can have one near the nipple or a cluster of small tumors in the narrow milk ducts farther from the nipple.

Symptoms of intraductal papilloma include:

Doctors may treat intraductal papillomas by surgically removing the papilloma along with the affected area of the milk duct.

Learn more about papillomas here.

A lipoma is a collection of fat cells. They can develop anywhere in the body. Lipomas usually appear just below the skin, but they can also form inside the mammary glands.

Lipomas are soft, moveable, painless lumps. A lump is usually the only symptom.

A deeper lipoma may put pressure on internal organs or nerves and cause associated symptoms. For example, a person with a lipoma on or near the bowels may experience nausea and vomiting, and constipation.

Lipomas are usually benign, so most people do not need surgery to remove them.

Some people may want to remove a larger or fast-growing lipoma or one that interferes with daily functions and life.

Read more about when removing a lipoma is necessary.

Mastitis is an infection in the breast tissue.

A blocked milk duct or bacteria entering the breast can cause a breast infection. This may be more common when breastfeeding.

Symptoms of mastitis include:

  • a lump or knot in the breast that is tender or sore to the touch
  • redness and swelling of the breast
  • pain or sensitivity when touching the affected area
  • a warm or a burning sensation in the affected area
  • flu-like symptoms, including fever and fatigue

Treatments for mastitis include antibiotics and OTC pain relievers. Untreated, mastitis can develop into a collection of pus, or an abscess, in the breast tissue. If an abscess forms, a person may need surgery to drain the pus.

Learn more about mastitis and how to treat it here.

Adenosis is a noncancerous breast condition characterized by abnormally large lobules in the breast. Adenosis can cause a lump that feels similar to a cyst or a tumor.

The enlarged lobules can contain calcium deposits, making it difficult for a doctor to distinguish them from tumors on a mammogram.

A doctor will use a biopsy to determine if the lump is adenosis or breast cancer. Before a biopsy, a medical professional will give the person a local anesthetic. They will then use a thin needle to remove a small tissue sample for laboratory testing.

People who have adenosis do not need treatment.

Learn about benign tumors here.

Phyllodes tumors are rare, making up less than 1% of all breast tumors. Most are benign, but around 1 in 10 are cancerous.

Some phyllodes tumors are borderline, meaning they fall between benign and malignant.

Phyllodes tumors feel like hard, painless masses. A doctor will usually perform a biopsy to diagnose these tumors because they are difficult to identify using mammograms and ultrasounds.

Surgery is the main treatment for phyllodes tumors.

Learn about what happens during breast lump removal surgery.

Sometimes, a lump in the breast can be cancerous.

Breast cancer is a collection of abnormal cells that develop in the tissue, ducts, or lobules of the breast. Breast cancer cells divide and multiply rapidly to form tumors that starve the surrounding tissue.

Breast cancer tumors are usually hard, irregular in shape, and painless.

Early diagnosis of breast cancer is vitally important. Some people can develop breast cancer symptoms before they notice a lump in the breast. Some of these symptoms include:

  • swelling or pain in the breast
  • discoloration, irritation, or rash on the breast skin
  • dimpling of the breast skin
  • changes in the appearance of the breast or nipple
  • nipple discharge

Learn more about the early signs of breast cancer here.

The signs of breast cancer are different for everyone. The most common signs are changes in the look or feel of the breast or the nipple and nipple discharge.

Typical warning signs of breast cancer include:

  • a lump with a different appearance or texture to the rest of the breast
  • a hard lump in the breast
  • a painful lump in the breast
  • dimpling or puckering of the skin
  • a change in the size or shape of the breast
  • swelling, warmth, redness, or discoloration on the breast

Learn about what types of breast lumps indicate cancer here.

The most common cause of breast lumps in males is gynecomastia. An imbalance of the hormones estrogen and testosterone causes it. It may affect pre-teen and teenage boys and males.

The symptoms include:

The condition tends to go away on its own. However, the condition may sometimes need treatment, such as treating the underlying cause of gynecomastia, when possible. Doctors may also recommend people discontinue certain medications if they have played a role in gynecomastia.

While it is rare, males can also develop breast cancer. According to the Centers for Disease Control and Prevention, about 1 in every 100 breast cancers in the United States affect males.

Common symptoms of breast cancer in males are:

  • a lump in the breast
  • swelling in the breast
  • redness in the breast
  • flaky skin in the breast
  • irritation or dimpling of breast skin
  • discharge from the nipple
  • pain in the nipple area

Learn more about the stages of breast cancer in males here.

To assess a breast lump, a doctor or another healthcare professional will review a person’s medical history and perform a physical examination of the breast. They may then use imaging tests to see if the lump is benign or cancerous.

Such tests may include:

  • Mammograms: These involve taking X-ray photos of the breast tissue.
  • Ultrasound scans: Doctors use these to investigate abnormal findings from physical exams or mammograms.
  • MRI scans: These create detailed images of the breast to investigate any abnormal findings from physical exams or mammograms.

People who have a very high risk of developing breast cancer should have frequent screenings.

If a doctor is still unsure about the nature of a breast lump after performing imaging tests, they may recommend a biopsy to determine if the lump is benign or cancerous.

Learn more about breast cancer from our dedicated hub.

While most breast lumps are benign, people should have a healthcare professional check for any new or unusual breast lumps.

Anyone who experiences any of the following warning signs should seek guidance from a medical professional:

  • a hard lump inside the breast, near the collarbone, or under the arm
  • swelling, discoloration, or rash on the breast skin
  • dimpling or puckering of the breast skin
  • changes in the size or shape of the breast
  • changes in the shape of the nipple
  • nipple turning inward, or retraction
  • unusual nipple discharge
  • a new lump that does not go away after one full menstrual cycle
  • unintentional weight loss

Learn about the links between age and breast cancer here.

Most breast lumps are benign. If a person finds a lump in either breast or both, they should schedule an appointment with a doctor for a diagnosis.

According to the ACS, breast cancer is the most common cancer among females, apart from skin cancers in the United States. The average risk of females developing breast cancer in their lifetime is around 13%.

Learn about the average survival rates of breast cancer here.

Regular breast screening, such as self-breast examinations and mammograms, plays a vital role in the early detection of breast cancer.

The National Breast Cancer Foundation recommends performing breast self-exams once every month.

The ACS state that females aged 45–54 should have annual mammograms.

All breasts are different, so what might be standard for one person may not be for another. People should try to become familiar with their breasts so that they can inform their doctor of any changes.