Breast cancer lumps can appear anywhere in the breasts. In females, they occur more often in the upper outer region, which is the top outer section of the breast, reaching toward the armpit. In males, breast cancer lumps are typically near or under the nipple.

Low angle view of a doctor and patient discussing breast cancer lumps while preparing for a mammography test -2.Share on Pinterest
izusek/Getty Images

Breast cancer is a serious health concern affecting millions of people worldwide.

Early detection is crucial for successful treatment. A primary way to identify breast cancer is to detect lumps in the breast tissue. However, it is important to note that not all lumps in the breast are cancerous.

This article explores where breast cancer lumps most commonly develop, how to identify them, associated symptoms, and the steps to take if a person discovers a lump.

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.

Was this helpful?

Although breast cancer lumps can develop anywhere in the breasts, they most commonly develop in the upper outer region of the breast.

The upper outer region of the breast is the part that is higher up and closer to the outer side of the chest, near the armpit area.

A 2017 study consisting of 110 women with breast cancer found that just over 60% of participants developed tumors in the upper outer region of the breast.

A 2022 observational study consisting of 290 women found similar results. The researchers found the breast cancer lumps developed in the following areas of the breast:

LocationNumber of participants
Upper outer quadrant70% (203 out of 290)
Lower outer quadrant4.5% (13 out of 290)
Upper inner quadrant10.3% (30 out of 290)
Lower inner quadrant14.1% (41 out of 290)
Central1% (3 out of 290)

Breast cancer is more common in females. However, males can also develop breast cancer. Typically, breast cancer lumps in males feel like a hard lump or pebble under the skin in the nipple area.

Breast cancer lumps have several specific characteristics. However, to diagnose breast cancer, a doctor must complete several types of tests.

Characteristics of breast cancer lumps include:

  • Texture and size: Breast cancer lumps typically feel firm or hard, unlike the surrounding breast tissue. They may range from very small to large, so size, alone, is not a definitive indicator.
  • Pain: Breast cancer lumps are often painless. However, having pain does not rule out breast cancer entirely, as some cancerous lumps can be tender or uncomfortable.
  • Movability: Unlike benign breast lumps, which are often movable and may change in size and shape throughout the menstrual cycle, breast cancer lumps are usually fixed and do not move around within the breast tissue.

Learn more about how to tell if a breast lump is cancerous.

Some additional symptoms and signs of breast cancer include:

  • Skin changes: Breast cancer can cause changes in the skin texture, such as dimpling or puckering. The skin over the affected area may also become thicker, reddened, or develop an orange-peel appearance.
  • Nipple changes: Changes in the appearance of the nipple, such as it turning inward, or discharge, other than breast milk, may indicate cancer.
  • Size or shape changes: Noticeable changes in the size or shape of one breast can be a warning sign.
  • Lymph node enlargement: Swollen lymph nodes in the armpit or collarbone area can indicate that breast cancer has spread beyond the breast tissue.

If a person discovers a lump or is experiencing any concerning breast changes, they should see a doctor for an examination.

The doctor may order imaging tests, such as mammograms, ultrasound, or MRI scans to assess the lump further.

A doctor may also recommend a lump biopsy. A biopsy is a procedure to remove a small sample of tissue from the lump. Experts look at the tissue sample under a microscope to determine if there is cancer.

If the tests confirm that the lump is cancer, the healthcare team will work with the individual to create a treatment plan. Treatment may include surgery to remove all or part of the breast and other treatments, such as:

  • chemotherapy
  • radiation
  • hormonal therapy
  • targeted therapy

The American Cancer Society (ACS) does not recommend that people perform breast self-exams as a part of a routine breast cancer screening schedule. This is because there is little evidence to suggest that doing so is beneficial for those with an average risk of breast cancer.

Instead, they suggest that people become familiar with how their breasts normally look and feel so they can report any changes to a healthcare professional.

The ACS suggests that a breast self-exam may be beneficial for those with a higher-than-average risk of developing breast cancer.

A person can perform the following steps when doing a self-exam of the breasts:

  • Stand in front of a mirror: Visually inspect the breasts, looking for changes in size, shape, or skin texture. Check for nipple abnormalities and signs of dimpling or puckering.
  • Raise arms: Inspect the breasts from multiple angles.
  • Lie down: Using the pads of the fingers, start in a circular motion and work from the outside in. Pay close attention to areas that feel different from the rest of the breast tissue.
  • Move fingers in an up-and-down pattern: While still lying down, feel the entire breast area, including the armpit.

Learn more about how to perform a breast self-exam.

Several noncancerous conditions can also lead to the formation of breast lumps:

  • Fibrocystic changes: Hormone changes throughout a female’s cycle can lead to the development of fluid-filled sacs doctors call cysts.
  • Fibroadenomas: These are solid, noncancerous masses that are often painless.
  • Infections: Infections in the breast tissue, such as mastitis or abscesses, can cause lumps and localized pain.
  • Trauma or injury: Bruising or injury to the breast tissue can result in the formation of a lump.
  • Lipomas: These are benign fatty lumps that can occur in the breast.

Breast cancer lumps can develop in any part of the breast, but the upper outer quadrant appears to be the most common location.

Identifying breast cancer lumps involves assessing their size, pain, and movability while being aware of other symptoms, such as skin changes, nipple abnormalities, and swelling.

Early detection through regular breast self-exams and prompt medical evaluation can significantly improve the chances of successful treatment.

Not all breast lumps are cancerous, and many benign conditions can also lead to their formation.

Breast cancer resources

Visit our dedicated hub for more research-backed information and in-depth resources on breast cancer.

Was this helpful?