A fibroadenoma is a solid breast lump that often causes no pain. It is: 
Round with distinct, smooth borders
Easily moved
Firm or rubbery
 A fibroadenoma often grows slowly. The average size is about 1 inch (2.5 centimeters). A fibroadenoma can get bigger over time. It may be tender or cause soreness a few days before your period. A large fibroadenoma may hurt when you touch it. But most often, this type of breast lump causes no pain. You can have a single fibroadenoma or more than one fibroadenoma. They can occur in one or both breasts. Some fibroadenomas shrink over time. Most fibroadenomas in adolescents shrink over many months to a few years. They then disappear. Fibroadenomas may also change shape over time. Fibroadenomas may get bigger during pregnancy. They might shrink after menopause.