A hematoma is a collection of blood outside a blood vessel, often after trauma, surgery, or bleeding from another cause.
Common symptoms include pain, swelling, bruising, tenderness, and sometimes a firm lump. Deeper hematomas may cause pressure symptoms depending on where they are.
Imaging helps when a hematoma may be deep inside the body, large, getting bigger, or pressing on nearby structures, or when doctors need to check whether there is ongoing bleeding.
Ultrasound, CT, or MRI can help show where the blood is, how much is present, and whether there are complications.
Some hematomas are watched, while others need drainage, surgery, or treatment of the bleeding source.
This entry explains the finding. The next step is having a radiologist interpret your specific scan, not a general definition.