Causes

By Mayo Clinic Staff

Breast lumps can be caused by:

  1. Breast cancer
  2. Breast cysts (which are fluid-filled sacs in breast tissue that are not cancer. The fluid in a cyst looks like water. An imaging test called ultrasound is used to find out if a breast lump is a cyst.)
  3. Fibroadenoma (a solid, benign growth within the breast glands. It is a common type of breast lump.)
  4. Fibrocystic breasts
  5. Intraductal papilloma.
  6. Lipoma (a slow-growing lump involving fatty breast tissue. It can feel doughy, and it is often harmless.)
  7. Trauma to the breast from a bump, breast surgery or other reasons.

Breast lumps also can be caused by health problems that can happen during breastfeeding, such as:

  1. Mastitis (an infection in breast tissue)
  2. A milk-filled cyst that's usually harmless.

Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.

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March 01, 2023

See also

  1. Breast cancer
  2. Breast Cancer
  3. Breast cancer chemoprevention
  4. Breast Cancer Education Tool
  5. Common questions about breast cancer treatment
  6. Infographic: Breast Cancer Risk
  7. Breast cancer staging
  8. Breast cancer types
  9. Breast cysts
  10. Breast pain
  11. Dragon Boats and Breast Cancer
  12. Ductal carcinoma in situ (DCIS)
  13. Fibrocystic breasts
  14. Genetic Testing for Breast Cancer
  15. Genetic testing for breast cancer: Psychological and social impact
  16. HER2-positive breast cancer: What is it?
  17. Male breast cancer
  18. Mammary duct ectasia
  19. What is breast cancer? An expert explains
  20. Paget's disease of the breast
  21. Paulas story A team approach to battling breast cancer
  22. Pink Sisters
  23. Recurrent breast cancer
  24. The Long Race Beating Cancer
  25. Weight Loss After Breast Cancer