A hematoma is a collection of blood, usually the result of bleeding somewhere inside the breast tissue. Hematomas can be caused by a number of things, such as trauma from a sports injury or car accident, or a hard bump to a weak blood vessel.

After a breast biopsy, bleeding can form a hematoma, or just the skin color that looks like a bruise. I’ll have more to say about this below.

After breast surgery, perhaps for breast cancer, or for cosmetic changes like breast reduction or augmentation surgery with implants, hematomas can also happen.

Talking Moose
Talking Moose
Have you ever had a bleeding nose, and a blood clot formed in the nasal passage?

Dr. Halls Dr. Halls
Many times when I was young. That blood clot is an example of a hematoma.

Blood that leaks into tissue, will usually clot, but sometimes it remains liquid.

How is a breast hematoma discovered?

Hematomas tend to be visible – the bruise color, and/or palpable.

In the breast, a small hematoma might be the size of a cherry. A medium sized hematoma could be the size of a plum. A ‘large’ breast hematoma might grow to the size of a grapefruit, except they tend to elongate to the shape of a banana.

Maybe the hematoma happens, without any symptoms, and then it shows up on a mammogram, like this example.
breast hematoma mammography

On the mammogram, it looks ‘mass-like’ and may need an ultrasound to figure out that it is just a hematoma, and not ‘local recurrence’ of the breast cancer.

Mammographic characteristics of breast hematoma

Hematomas are usually quite obvious and predictable on mammogram and particularly on corresponding ultrasound, so they do not usually require biopsy. Very small hematomas may not even be detected on a mammogram, but when they are large enough to be seen, they typically appear as a well-defined oval mass. Less frequently, a hematoma may appear on the x-ray as a nodular image (a nodule usually refers to something with solid elements) with well-circumscribed margins, possibly with an edema (a build up of fluid, – basically water) around the periphery. Hematomas frequently occur in combination with a breast seroma (accumulation of clear ‘blood-serum’) and that can cause a little bit of ambiguity on the mammogram, but usually this is fully diagnosed with a subsequent ultrasound.
hematoma of the breast

Breast hematomas may leave scar tissue when they resolve

As hematomas tend to resolve on their own, the mass will likely not show up on a follow-up mammogram. However, as they dissipate, fibrous tissue (scar tissue) can grow in the area of the former hematoma and this can give an appearance of a ‘proliferative’ growth (which could possibly indicate breast cancer cell growth). This is not unexpected, but will still require the screening doctors to take a closer look. Usually this residual fibrous-scar tissue will appear as an architectural distortion on the mammogram; an oddly rearranged segment of breast tissue with a ‘spikey’ outline.

Dr. Halls Dr. Halls
That’s right. A hematoma can mostly disappear but leave behind a fibrous scar, that looks like an architectural distortion.


These sorts of ‘focal asymmetries’ are very common and occur in about 60% of all breast hematomas, and an ultrasound will usually be sufficient to make the situation clear. But sometimes even the ultrasound can be inconclusive.

The transitional nature of hematomas can present as a strange combination of liquid and solid elements. They change appearance over time. If there is any uncertainly, (perhaps a finding of irregular margins and a non-homogeneous hypoechoic nodule) a biopsy will undertaken.

Breast hematomas may produce calcifications

Calcifications may develop in later stages of the dispersal of a hematoma, but these are quite easily distinguished from the common microcalcification patterns associated with ductal carcinoma, and are to be expected.

How is a breast hematoma treated?

Hematomas usually resolve on their own, but that can take quite a while (4-6 six weeks, sometimes longer). Very large hematomas might have to be surgically drained. That is usually the end of the issue, but there are cases of ‘spontaneous recurrence’ of breast hematomas.

Breast hematomas present some risks for secondary health complications

Hematomas need to be treated and closely followed because they do present risks for secondary health complications. While completely unrelated to cancer or anything of that nature, the pooled blood can become infected with bacteria, leading to inflammation, swelling, and fever. Skin discoloration is also a common side-effect. Special concern must be noted for women with any medical history of hemopathy and coagulation disorders, or those taking anticoagulant drugs. Some doctors might even suggest a patient keep away from certain pain killers (such as aspirin) which have been known to hinder the ‘blood-clotting’ process.

Are hematomas of any concern for breast cancer?

Hematomas are not related to breast cancer. They are caused be damaged blood vessels via surgery. But, it is quite important to get a clear differential diagnosis of hematoma if a patient is undergoing treatment for breast cancer. There are a couple of reasons for this. The asymmetric density and increased skin thickness that sometimes develops as the hematoma retreats often has a mammographic appearance that can mimic some breast carcinomas, so that has to be ruled out. Also, it is possible that an occult (hidden) breast tumor could be causing the internal bleeding. A hemorrhage caused by an intracystic tumor (a breast-cancer growth growing in the middle of a cyst, surrounded by fluid) might also be a possibility, though rare.

Hematomas can actually be helpful in removing breast tumors in some cases

Though hematomas following core biopsy procedures (for a suspected breast carcinoma) are quite rare, when they do develop it presents a certain pragmatic opportunity for subsequent surgical treatment. If the surgeons have decided to perform a lumpectomy, they can sometimes use a ‘sonographically visible hematoma’ (induced accidentally by the biopsy) as a localizing device and get very accurate surgical margins, and that’s always a desired outcome in treating DCIS and breast cancer.

How to prevent hematoma from a biopsy

Dr. Halls Dr. Halls
I do a lot of breast core biopsies, and here’s how I prevent hematomas

For the first minute after a core biopsy, I use my own hand and put pressure on the breast. Still wearing a surgical glove, pressing on a thin piece of gauze on the skin puncture site, but also pressing over the lump that was biopsied.

Then we put on a bandaid, and ask the patient to place her own bare hand on her breast, and apply pressure by herself for another 5 minutes. My secret, is to use a bare hand on the skin, NOT pressing on a thick sterile folded-up towel, and not pressing on a cold-pack or warm-compress. I believe bare-hand pressing on skin is the only way to achieve enough pressure. Conversely, I believe cold and warm packs lead to insufficient pressure. The fact that my thousands of breast biopsies have never caused a hematoma, validates my belief.

Hematoma versus seroma

When leaked blood accumulates in a fluid collection, at first it clots. later it separates into a yellow fluid (which is the “serum” component of blood), and the solid fibrin component of a blood clot. On ultrasound, the seroma fluid looks clear, without any echos floating in the fluid. Fresh blood on the other hand, has red blood cells in the fluid, which cause echos that give ultrasound some texture of speckles visible in the fluid. Seeing echos in the fluid is how ultrasound decides whether something is called a hematoma or a seroma. When you drain a breast fluid collection with a needle, if the fluid looks clear yellow, we call it a seroma, if it looks dark red like old blood, we call it a hematoma.

Why drain hematomas and seromas?

In the breast after surgery, the tissue that was cut by the scalpel, will normally desire to heal-itself and join back together. But it can’t heal if the cut surfaces aren’t touching each other. If there is fluid filling the gap between tissue surfaces, then they can’t join together and heal. So this is a good reason to have a needle drainage procedure. Another good reason, is that a hematoma that is large, can stretch the skin, stretching the skin incision. That makes the incision heal slower and end up looking like a wider scar. Another reason is simply to reduce pain. A hematoma stretches the tissues around it, and nerve endings don’t like being stretched or pushed around, so they send pain signals to the brain. If you remove the hematoma, the nerve endings no longer complain about it.

When I try to drain breast hematomas with a needle, if ultrasound shows the fluid is fairly clear, then usually it can be drained completely. But if the fluid is a hematoma that still has echogenic speckles in the fluid, that means there are lots of blood cells floating around in the fluid, like a slurry of tiny blood clots. Those tend to plug up a needle. So there is a tendency for some hematomas to be not completely drainable, at one moment in time. BUT, if you wait a week or two, the hematoma changes into seroma and fibrin-clot, and fluid becomes drainable again. This is why it may take several drainage procedures, spread out over time, to get rid of them.


Did I miss any questions?

  • What does a hematoma feel like and how does it resolve? It hurts quite a lot and makes your skin feel tight and your breast feels hard and swollen. Small hematomas can resolve completely. Medium sized ones can take a long time to resolve completely, like many many months. Large ones should be drained.
  • Can infection happen? Yes, but it’s hard to tell, so often the doctor gives antibiotics just to be safer.
  • So hematomas last a long time? Hopefully not months, but I’ve seen a few that stayed around for a few years. I remember one patient, who would deliberately ask each doctor, so she could humiliate them when they said months, and she’s say, wrong, this one has been here for two years.
  • What is evacuation of a hematoma? If you have a syringe on a needle, put the needle through the skin, into the hematoma (but freeze the skin first with local anaesthetic), when you suck out fluid into the sryinge, that’s called evacuation. There are other ways to create suction besides syringes.


  1. Rahman, RL., Iuanow, E., Crawford, S., Quinlan, R., Sonographic Hematoma-Guided vs Wire-Localized Lumpectomy for Breast Cancer A Comparison of Margins and Volume of Resection . Arch Surg. 2007;142:343-346.
  2. Farrokh1, D., B. Zandi, B., Hashemi, J., Breast hematoma simulate as carcinoma: A case report and a review of the literature. Rev. Hosp. Clin. v.56 n.6 São Paulo nov./dez. 2001
  3. Wolf G, Hohenbgerg G, Hagar N. Mammagraphic and sonographic appearances by traumatic changes in the female breast. Rufo. 1984; 4 (2): 204-208.
  4. Gollentz B, Ballarini P, Rossier S. Breast hematoma and cytosteatonecrosis. a Propos of 55 cases. J Radiol. 1990; 71 (1): 33-43.
  5. Shrotira, S., Ghilchik, MW., Breast haematomas: same appearance, different diagnosis. Br J Clin Pract 1994; 48:214-215.
  6. Diebold J, Hahn. T. Evaluation of the stereotactic 8G Vacuum-aspirated breast biopsy in the histologic evaluation by suspicious mammography. Invest Radiol. 2005: 40(7): 465-71.
  7. Kuni, CC., Weisensee, AM., Le, CK., Mammographic changes following conservation surgery and radiation therapy for breast cancer. Breast Dis, 1992; 5:69-81.

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