A breast lump is a growth of tissue that develops within your breast. It may be described as a mass, growth, swelling, thickness or fullness.

A breast lump can vary in the way it looks and feels. If you have a breast lump, you may notice:

Sometimes, a breast lump is a sign of breast cancer. That's why you should seek prompt medical evaluation. Fortunately, however, most breast lumps result from noncancerous (benign) conditions.

1. Breast cancer
2. Breast cysts
3. Fibroadenoma
4. Fibrocystic breasts
5. Hamartoma, a noncancerous tumor in the breast
6. Injury or trauma to the breast
7. Intraductal papilloma, a noncancerous, wart-like growth in a milk duct
8. Lipoma
9. Mastitis
10. Milk cyst (galactocele)

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

Source: mayoclinic.org

• The breast lump is new or unusual and feels different from surrounding tissue or from tissue in your other breast
• The breast lump doesn't go away or gets bigger after your next menstrual period
• The breast lump changes — gets bigger, firmer or more defined from surrounding breast tissue
• You have bloody, possibly spontaneous, discharge from your nipple
• You notice skin changes on your breast, such as redness, crusting, dimpling or puckering
• Your nipple is turned inward (inverted), although it isn't normally positioned that way

Source: mayoclinic.org