What is the Difference Between Seroma and Hematoma?

06/25/2025 • Felipe Moraes

A seroma and a hematoma are both surgery-related complications that can affect wound healing, but they have different characteristics:

Seroma:

  • Contains serous fluid, which is composed of blood plasma that has seeped out of ruptured small blood vessels and the inflammatory fluid produced by injured and dying cells.
  • Sterile collection of fluid under the skin, usually at the site of a surgical incision.
  • Common after breast surgery, abdominal surgery, reconstructive surgery, neck surgery, thyroid and parathyroid surgery, and hernia repair.
  • Diagnosed based on signs on the skin or through CT scans.
  • Prevented by optimal surgical hemostasis, placement of drains, and rapid evaluation and evacuation of postoperative fluid collection.

Hematoma:

  • Contains blood outside of blood vessels, resulting from a damaged blood vessel wall and blood leakage into surrounding tissues.
  • Occurs when a pool of blood collects under the skin after surgery, looking like a bruise.
  • Common after injuries to blood vessels, such as veins, arteries, or capillaries.
  • Treatment depends on severity, with small hematomas potentially resorbing after a few days, while more severe hematomas may require surgery to drain the accumulated blood.
  • A risk of infection is associated with hematomas, as there is no blood supply to the collection of old blood.

In summary, a seroma is a collection of serous fluid under the skin, typically at the site of a surgical incision, while a hematoma is a collection of blood outside blood vessels. Both complications can impact wound healing, but they have different characteristics and treatment approaches.

Comparative Table: Seroma vs Hematoma

Here is a table comparing the differences between seroma and hematoma:

Feature Seroma Hematoma
Definition A collection of clear serous fluid in the wound A collection of blood in the wound
Formation Triggered by abdominal wall reconstructions, hernia repairs, removal of breast implants, and other surgeries Triggered by post-trauma, injury, and surgery
Appearance Clear fluid under the surface of the skin, typically around the area of an incision Pool of blood under the skin, often looking like a bruise
Effect on Wound Healing May have negative effects on wound healing Increases wound tension, affecting the wound healing process and reducing tissue perfusion
Diagnosis Diagnosed through physical examination and imaging tests Diagnosed through physical examination and imaging tests
Treatment Often resolves on its own, but can be drained surgically if needed Often resolves on its own, but can be drained surgically if needed
Prevention Prevention includes attention to surgical hemostasis and placement of drains Prevention includes proper surgical technique, tissue sealants, platelet gel, and quilting sutures

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