Dog with a Bleeding Tumor or Lump: What to Do (FAQ with our Vet)

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vet healing and bandaging a dog wound (close up of the dog's leg)

Unfortunately, our dogs are not immune to lumps, bumps, or tumors. They’re actually very common. It’s also fairly common for those same lumps and bumps to bleed periodically. Whether the bleed is directly related to the tumor type or to your dog scratching or nibbling the lump, seeing blood can be troubling. Don’t worry, we’re here to help! In this article, we will look at what can be done to help your dog.

What Happens When a Tumor or Lump Bleeds?

There are different situations:

1. There are some types of tumors that bleed because they are actually coming from blood vessels.

2. There are tumors or lumps that bleed because the skin covering them gets disrupted. This is often because the tumor is causing your dog some discomfort, and they start to scratch or chew at it.

Of course, the first reason is more of a concern than the second reason, but both are alarming.

“If a tumor or lump bleeds an excessive amount, your dog may be in immediate danger. If it just bleeds small amounts over time, there’s not immediate danger, but it does open them up to the chance of infection and other issues.”

Dr. Chyrle Bonk


What Can You Do At Home to Stop a Bleeding Tumor on a Dog?

Whether your dog has a new lump or a previously diagnosed tumor, when it starts to bleed, it can be very alarming. Fortunately, there are some things you can do to make your pup more comfortable.

  1. Stay calm. Seeing blood can elicit some fear and get your adrenaline pumping, so take a big deep breath and then find out where the blood is coming from.
  2. If you can, apply pressure to the bleeding with a towel or other absorbent material. If the lump is in a good area, try to snuggly wrap it.
  3. Call your veterinarian. Maybe this is the first time or the 31st time your dog has had a bleeding tumor or lump, but your vet will want to know about it. They may ask you to come immediately if there’s a lot of blood or give you the next available appointment if you’re able to get it under control.
  4. Keep the lump covered until your veterinary appointment to help prevent further bleeding and to keep it clean.

One dog owner asked us: “I just noticed a lump on my dog and it’s bleeding. How do I find out if it’s a cancerous lump? Do dog benign tumors bleed?”

The only way to know what makes up a lump is by visiting your vet. They will take a sample of the lump to find out if it is cancerous or not. Just looking at a tumor or seeing it bleed will not tell you if it’s cancerous or not since benign tumors can also bleed.

What Will My Veterinarian Do For My Dog With a Bleeding Tumor or Lump?

“Hopefully your quick and careful at-home care has gotten your dog’s bleeding lump under control before you get to the vet’s office. If not, that will be the first thing your vet will tackle. From there, they will decide how to fix this issue permanently. If the lump is previously undiagnosed, your vet’s going to want to find out what it is. They will take a sample of it either with a needle and syringe or by biopsy and analyze the results. “

Dr. Chyrle Bonk

Veterinarian at

Some samples may need to be sent to another lab for proper diagnosis. Learn more about the costs of FNAs and biopsies.

With any luck, the tumor or lump is small enough and in a favorable spot to just remove-get it out of there so that it can’t bleed anymore.

If the lump is in a spot where surgery isn’t an option, cryotherapy or electrocautery may be tried. For cancerous tumors, chemotherapy or radiation may be discussed as well.

Types of Bleeding Tumors in Dogs

Any tumor or lump in the skin can bleed, especially if your dog is bothered by it and scratches or chews on it. Tumors and lumps can also bleed if they are big enough to get caught and torn on something.

That being said, there are some tumor types that can bleed because that’s the type of tumor they are. These types of tumors tend to be more worrisome because of the risk of bleeding excessively to the point that it’s dangerous for the pup.


This is a type of tumor that comes from the blood vessels. They can happen anywhere on the body, and as you can imagine, are capable of bleeding because, well, they’re made up of blood vessels. Hemangiosarcomas are the malignant type of this kind of tumor in that they have a tendency to spread to other areas. They are a high-risk type of tumor because of their spreading capabilities and the chance that they could cause excessive bleeding at any time.

hemangiosarcoma blister or lump on dog skin (closeup)

Hemangiosarcomas arise from a mix of genetics and environmental factors. Tumors can pop up on internal organs and will only show up as signs of weakness, paleness, or collapse if they start to bleed. Tumors on the skin can show up as purplish-reddish bumps or swellings on or under the skin. They may bleed spontaneously. The best treatment for hemangiosarcoma is surgical removal +/- chemotherapy if the cancer has already spread.


Hemangiomas are just like hemangiosarcomas minus the spreading capability. This means that they are benign tumors but can still be serious. Hemangiomas also come from blood vessels anywhere in the body and can spontaneously (and dangerously) bleed. They can show up on internal organs, not causing any signs until they start to bleed, or they can show up as red bumps on the skin. Either way, your vet will diagnose using a biopsy or take a sample with a needle to analyze under the microscope.

Hemangiomas should also be removed surgically to prevent any bleeding, but the prognosis is much better than with hemangiosarcomas since they don’t spread to other areas.


Let’s just say this one more time: any tumor or lump can bleed. It doesn’t take a specific type. Skin tags, warts, fatty tumors, or mast cell tumors can all bleed, especially if your pup is worried by them and overlicks, scratches, or nibbles at them.


How do you know if a bleeding tumor or lump is an emergency?

If you know that your dog has a vascular tumor like a hemangioma or hemangiosarcoma, bleeding can be very detrimental, so seek veterinary care as soon as possible. If your dog has another tumor type that is bleeding and you aren’t able to get the bleeding under control by applying pressure, get emergency care.

What does it mean when a tumor or lump on a dog bleeds?

Vascular tumors may bleed spontaneously because they come from blood vessels, and any extra pressure or bump can set them to bleeding. Other tumors can bleed if they are scratched, chewed, or scraped. This usually means that they are in a spot that is bothering your dog or that they are painful, and they want them gone.

Does a bleeding cancerous tumor impact my dog’s life expectancy?

This depends on the type of cancerous tumor that your dog has. Vascular tumors that bleed can be life-threatening, especially if they’re internal. Other types of tumors may bleed and not have any impact on life expectancy. Be sure to have any lump or bump looked at by a vet to determine what it is and what to do about it.

What happens when a tumor or lump bleeds?

There are a few tumors out there that actually come from blood vessels. These are dangerous tumors to bleed because they have a huge blood supply backing them, making it possible for a dog to lose a lot of blood very quickly. Other tumors can also bleed, especially if they’re bothersome to your dog and they scratch or chew on them, causing a bleeding wound. These tumors are less likely to cause excessive blood loss but can make quite a mess and then become infected.

Are bleeding tumors painful for dogs?

Some tumors can be painful, especially if they’re in an area that sees a lot of movement, such as the groin or armpit, or where they may get easily irritated.


  • Dr Chyrle Bonk, Veterinarian

    Dr. Chyrle Bonk received her Master in Animal Science from the University of Idaho and her Doctorate of Veterinary Medicine (DVM) from Oregon State University in 2010. She has over 10 years of experience in small animal veterinary practice, working for a veterinary clinic in Idaho.

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Disclaimer: This website's content is not a substitute for veterinary care. Always consult with your veterinarian for healthcare decisions. Read More.

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