Definition of Breast trauma

Breast trauma: Physical damage to a breast. If a breast is injured by trauma, tiny blood vessels may rupture to cause localized bleeding (a hematoma). The hematoma can be felt as a lump. Trauma to the breast can also damage the fat cells in the breast tissue, a condition called fat necrosis. Fat necrosis can form a lump in the breast. This type of lump is not cancer.