What causes hematoma after mastectomy with reconstruction surgery?

Blood: After mastectomy then reconstruction that gets a hematoma is caused by blood. The blood vessels supply oxygen to the breast tissue. This can occur with any surgery and will most likely resolve on its own. It may require drainage. Talk to your surgeon and they will discuss it with you.

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A collection: Of blood that occurs after surgery of this type. With surgery tissues and tissue plains are interrupted causing some bleeding. Typically most of the bleeding is stopped. Drains are general placed to remove the fluid that accumulates. Sometimes a hematoma or seroma occurs requiring drainage. See your surgeon routinely postoply until the problem is resolved.