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What is Breast hematoma and explain in detail?
Breast hematoma  is a collection of blood within the breast. It arises from internal bleeding (hemorrhage) and may arise due to trauma (breast injury or surgery) or due to a non-traumatic cause.

Symptoms
Symptoms may include visible discoloring (ecchymosis), breast pain, and swelling.
The symptoms may be similar to those of fibrocystic breast changes.

Causes
A breast hematoma may appear due to direct trauma to the breast, for example from a sports injury or a road accident, for example a vehicle collision in which a seat belt injury occurs.
Hematoma can also be a consequence of breast surgery, usually due to post-operative bleeding. Bleeding may occur shortly after the intervention or a number of days later and can occur for cosmetic surgery (for example breast reduction or breast enhancement) and for non-cosmetic surgery (for example lymph node removal, lumpectomy, or mastectomy). More rarely, hematoma can result from breast biopsy.
Rarely, a breast hematoma can also occur spontaneously due to a rupture of blood vessels in the breast, especially in persons with coagulopathy or after long-term use of blood-thinning drugs such as aspirin or ibuprofen.

Pathophysiology
Small breast hematomas often resolve on their own within several days or weeks by means of reabsorption of the blood