Hemangiosarcoma in Dogs: What Happens and Saying Goodbye

Hemangiosarcoma in dogs is a cancer of the cells that form blood vessels, most commonly affecting the spleen or heart of older, large breed dogs. It can also occur in the liver, the skin, or the muscle. It makes up approximately 5% of cases of cancer in dogs. For some families, the first news comes when their dog seems weak, a vet finds a ruptured tumor, and decisions come fast.

We're so sorry you're facing this, whether you're in a waiting room right now or at home trying to understand what the vet said. Surgery, chemotherapy, comfort care, and euthanasia are all paths families take. You don't have to read all of it. Go to the part you need today, whether that's an emergency, a treatment choice, or a goodbye, and leave the rest for later.

If your dog has died, there's a section written for you further down, and you can go straight there.

Key Takeaways

• Hemangiosarcoma is a cancer of blood vessel cells. It most often grows in the spleen or heart of older, large-breed dogs, and it may cause few or no signs early on.
• Collapse, severe weakness, pale gums, and fast breathing or trouble breathing can mean a hemangiosarcoma in the spleen or heart is bleeding. If your dog is showing these now, get help from a vet or an emergency clinic. These signs are about getting help now, not about how much time your dog has.
• After a rupture, decisions can come fast, sometimes within minutes. You can ask whether your dog is stable, what each option involves, and what it would cost.
• For hemangiosarcoma in the spleen or heart, treatment aims to slow the cancer and delay bleeding. A tumor confined to the skin itself can sometimes be cured with surgery.
• If your dog has died and a vet saw your dog, that vet may be able to talk through their findings.

What Is Hemangiosarcoma in Dogs?

Hemangiosarcoma is a cancer that grows from blood vessel cells. Because blood vessels run throughout the body, it can appear in many places, but it occurs primarily in the spleen, followed by the heart, skin, and liver. In the U.S., it's estimated that more than 50,000 companion dogs develop this disease every year.

Vets sort it into two broad groups. The internal form, called visceral, grows in organs such as the spleen, heart, and liver. The external form grows in the skin, the tissue just under it, or the muscle. The two can behave very differently, from treatment to outlook.

Hemangiosarcoma is more common in certain breeds, such as German Shepherds, Golden Retrievers and Labrador Retrievers. University of Minnesota researchers add Portuguese Water Dogs, Bernese Mountain Dogs, Flat-Coated Retrievers, Boxers and Skye Terriers to that list, and they see it more commonly in dogs older than 6 years than in younger dogs.

In the Golden Retriever Lifetime Study, hemangiosarcoma contributes to 70% of cancer-related deaths among the dogs enrolled. Still, any dog can be affected, and one recent study found that small dogs with hemangiosarcoma had survival similar to large-breed dogs. A breed on a list isn't a diagnosis.

If your dog has just been diagnosed with cancer of any kind, our guide to the first steps after a dog cancer diagnosis covers questions to ask, finding an oncologist, and how families weigh treatment.

What Skin Hemangiosarcoma Looks Like

When hemangiosarcoma is confined to the skin, it usually appears as solitary or multiple superficial nodules or papules with a reddish-to-blackish color. It can also look like a more well-defined raised mass on the skin that can rupture and bleed outside of the body, or like a bruise or blood blister.

Cornell notes that sun is thought to play a role in the skin form. Dogs of breeds with light skin and sparse hair are at higher risk, mainly for the sun-linked type. Breeds reported most often: Pitbull, Whippet, Greyhound, Boxer, Beagle, and Dalmatian. If your dog has this form, a vet can tell you whether limiting sun exposure matters. The outlook for the skin form is generally better than for the internal form.

One proposed staging system for skin tumors runs from I to III: stage I is confined to the skin itself, stage II reaches the tissue beneath it, with or without nearby or distant lymph nodes involved, and stage III has spread elsewhere in the body.

Hemangioma vs. Hemangiosarcoma

The benign counterpart of hemangiosarcoma is hemangioma, a noncancerous growth of the same cells. On the skin, the two can be easily confused on a needle sample because blood can dilute it.

Early Signs of Hemangiosarcoma in Dogs

Hemangiosarcoma may have little to no signs early on, before a tumor bleeds. When signs do appear, they can be mild. This list describes what vets see across many dogs, and yours may show some of it, all of it, or none of it:

• Tiredness or weakness.
• Less interest in exercise or play.
• A smaller appetite.

If your dog shows any of these now, a vet visit is worth it to help sort out what's going on.

How Vets Diagnose Hemangiosarcoma

A vet may suspect hemangiosarcoma after a dog collapses and has bleeding in the belly or around the heart, or after finding a mass on the spleen or heart during an exam or ultrasound for something else. Testing can include chest X-rays, a belly ultrasound, blood work, and sometimes a heart ultrasound (echocardiogram). Blood work alone is neither sensitive nor specific to confirm the diagnosis, so it's only one piece of the picture.

Vets often reach a diagnosis from the scans and the bleeding, and a biopsy confirms it. A needle sample of a spleen mass often is unable to determine whether it's cancer.

What Happens When Hemangiosarcoma Ruptures

The blood vessels inside a hemangiosarcoma tumor are malformed, so blood tends to pool and clot inside them. Parts of the tumor lose their blood supply and die. Then the tumor can rupture, and blood collects in the belly, the sac around the heart, the chest, or under the skin, depending on where the tumor is.

If your dog died suddenly, there's a section for you near the end of this guide.

Signs of Internal Bleeding in Dogs

Dogs with hemangiosarcoma of the spleen or heart are at risk of the tumor rupturing and bleeding, and a bleed is often life-threatening. Signs of a bleed can include:

• Collapse or severe weakness.
• Pale gums.
• Fast breathing or trouble breathing.

If you see any of these, call a vet or the nearest emergency clinic now. These signs are about getting help, not about how much time your dog has.

If Your Dog Is Bleeding: What Happens and What to Ask

After a rupture, families and vets may face difficult decisions within minutes of diagnosis, and you can ask the vet anything along the way.

When surgery is the plan, vets often run blood tests to check blood counts, clotting, and organ function. Some dogs get supportive care such as fluid therapy or blood transfusions before surgery. Chest X-rays and a belly ultrasound look for spread large enough to see.

Questions that can help:

• Is my dog stable right now, or still bleeding?
• Did the X-rays and ultrasound show any sign of spread?
• If I choose surgery, what would recovery ask of my dog?
• What would comfort care look like if I bring my dog home?
• Can I be with my dog for euthanasia, and how does it work here?
• Can I have an itemized estimate for each path?
• If I say goodbye here, what aftercare options do I have, and can I take some time before deciding?

Comfort care and euthanasia sit alongside surgery as real choices, and you can ask about any of them, in any order.

If You're Deciding About Surgery: What a Spleen Mass Can Be

If surgery is on the table, it can help to know that up to two-thirds of dogs with splenic masses have a cancerous mass, most often hemangiosarcoma, and some masses are benign, such as a hematoma, a pocket of clotted blood. If a vet saw your dog, whether or not surgery was part of the plan, they may be able to explain what they found.

Treatment Options for Hemangiosarcoma in Dogs

There's no cure for hemangiosarcoma in the spleen or heart. By the time it's diagnosed, it's almost certainly present in other sites, even though metastases may not be visible, so treatment aims to slow the cancer and delay bleeding. Families often move between these paths as things change.

Surgery

For a tumor on the spleen, the surgery is a splenectomy, which removes the whole spleen. It helps reduce the risk of potentially life-threatening internal bleeding from a ruptured tumor and is one of the options when a tumor has already bled.

Most animals will remain in the hospital for 24–48 hours after surgery so the team can watch their heartbeat and blood volume. At home, activity is usually limited to short leash walks for the first two weeks while the incision heals.

If scans show spread, some vets bring up surgery: removing a visible tumor may be recommended for hemangiosarcoma patients whose condition is otherwise stable even if there is widespread metastasis, to prevent or delay a bleed. Some families choose surgery at that point, and some choose comfort care or euthanasia.

Chemotherapy

Chemotherapy delivered after surgery may delay metastasis, the spread of cancer to other places in the body. Standard chemotherapy typically consists of the drug doxorubicin, given once every two to three weeks for five treatments, and it's generally well tolerated.

Side effects can include nausea and a reduced appetite. Veterinarians will monitor pets closely during treatment and adjust medications as needed. If your dog has a harder time with it, you can talk with the vet about changing the plan or stopping.

When the cancer has already spread, or surgery isn't possible, some vets offer chemotherapy to try to slow it, and the vet can talk through what it could do for your dog.

Treating Hemangiosarcoma of the Heart

Surgery is rarely possible for tumors on the heart, so treatment for this form may combine radiation and chemotherapy instead.

Treating Hemangiosarcoma of the Skin

When the tumor is confined to the skin with no signs of spread, dogs can be cured when complete lesions are removed, especially when the tumor is linked to sun damage. When the skin form extends deeper into the muscle, Cornell notes it can behave as aggressively as the splenic and cardiac forms, which the vet weighs when planning treatment.

Comfort Care and Hospice

Some families bring their dog home on comfort care. Merck describes it as care that allows pets to live comfortably in familiar surroundings, with a plan the vet adjusts as things change. A veterinary end-of-life service can include on-call availability of the veterinarian to provide urgent care as needed, in-home care, pain relief, and in-home euthanasia if a family chooses it.

Two supplements sometimes come up alongside other treatment: Yunnan Baiyao, which is a Chinese herb used in patients with bleeding conditions, and I'm-Yunity, a turkey tail mushroom supplement. If your dog takes either one, or you're considering it, talk to your vet. Our guide to how pet hospice works walks through what a hospice plan looks like day to day, and our directory lists pet hospice and palliative care providers you can search by ZIP code or city.

Euthanasia

Euthanasia is a path families take at many points: in an emergency room after a rupture, during surgery when the vet calls with what they've found, after surgery shows the cancer has spread, or after time on comfort care at home. It can happen at a clinic or, with an in-home vet, at home. If the goodbye is still ahead, you can ask to be with your dog and whether your dog can be sedated first.

Our dog end-of-life resources cover hospice, euthanasia, and grief support.

How Much Does Hemangiosarcoma Treatment Cost?

One emergency clinic's 2023 guide puts a splenectomy at $1,500 to $4,000 or more, and chemotherapy, radiation, and oncology visits add to that. Prices vary a lot by region and hospital, so these ranges are a starting point for the conversation, not a quote:

• Splenectomy: Northside Emergency Pet Clinic's 2023 guide gives a range of anywhere from $1,500 to $4,000 or more, depending on location, tests, anesthesia, medications, and how long a dog stays in the hospital.
• A first visit with a veterinary oncologist: anywhere from $125-$250 for an initial consultation, before any treatment.
• Chemotherapy: from $150 to about $600 per dose, depending on the drug.
• Radiation: about $1,000 to $1,800 for a palliative course, the kind used for comfort.

You can ask for an itemized estimate at any time, including in the emergency room, and ask what each part of the plan is for.

Insurance policies vary widely both in terms of coverage and in terms of costs, so if your dog has pet insurance, call the insurer with the diagnosis.

How Long Do Dogs Live With Hemangiosarcoma?

These figures describe groups of dogs on specific treatments, not how long your own dog has. For hemangiosarcoma of the spleen, survival is usually counted in weeks to months; the skin form generally has a better outlook, and sources differ on the heart form. Here's what veterinary sources report for the spleen:

• With surgery alone: Cornell gives an average survival time of two months. The University of Minnesota's median for dogs treated with surgery is one to three months, meaning half the dogs lived longer than that.
• With surgery and chemotherapy: Cornell reports a median survival time of four to six months for dogs treated with both.
• At one year: Cornell says less than 10 percent of dogs are alive one year after diagnosis. The University of Minnesota puts the figure at only 10-15% of dogs diagnosed with hemangiosarcoma of the spleen alive a year or more after diagnosis.

Without treatment, survival for hemangiosarcoma in any location is usually counted in weeks, although some can survive for several months, the University of Minnesota team writes.

For hemangiosarcoma of the heart, Cornell describes the outlook as similar to that of splenic HSA, the spleen form. The University of Minnesota team writes that tumors in the heart, liver and other internal organs generally do worse than tumors of the spleen. In contrast, the prognosis for tumors that are localized to the skin is better than for tumors of the spleen.

In one study of dogs with skin hemangiosarcoma treated with surgery alone, median survival was 780 to 987 days, with 79%, 60%, and 44% of dogs alive in the first, second, and third years after diagnosis. That study included dogs with or without signs of sun damage.

For a dog at home on comfort care, ask a vet what a bleed looks like and what to do if one happens, so you have a plan ready.

Is Hemangiosarcoma Painful for Dogs?

The internal form usually isn't painful while it grows. University of Minnesota researchers describe a cancer that does not cause pain or discomfort as it develops. If your dog is bleeding now, call a vet right away. No matter your dog's form, pain relief is part of care, and a vet can adjust it as things change.

Depending on where they grow, tumors under the skin or in the muscle can cause local pain, lameness, or functional impairment in nearby parts of the body. Merck notes that pain can often be managed, and a vet can talk you through the options.

Our guide to end-of-life pain management covers the medications and comfort measures a vet may offer.

Final Stages of Hemangiosarcoma in Dogs: What to Watch For

In the final stages of the internal form, the cancer has usually spread, most often to the lungs and to organs in the belly such as the liver. In most dogs treated with surgery, the cancer will spread to other sites throughout the body 1-3 months after surgery. Two kinds of changes matter here:

• Signs of a bleed, such as collapse or pale gums, which need a vet right away.
• Changes in how your dog lives day to day, such as eating, energy, mobility, and comfort.

Vets weigh these day-to-day changes when helping a family think about quality of life. VCA Canada's Vets To Go team lists appetite, energy level, body condition, mobility, pain, and cognitive function. Our guide to the HHHHHMM quality of life scale explains a scoring tool vets can use to look at quality of life as a whole.

If you're living in this stretch with your dog, our anticipatory grief resources cover the grief that can start before a loss, including the waiting, with practical ways to get through the days.

When to Say Goodbye to a Dog With Hemangiosarcoma

Because a bleed can happen at any time, some families choose a planned goodbye at home or at a clinic; some decide during a bleed; and some plan for both. A vet can help you look at the whole picture, from appetite and energy to pain and comfort.

One question many families find useful to ask the vet: If this were your dog, what would you be watching for? If you'd like help thinking it through, our directory lists quality-of-life consultations, where a vet assesses your dog's comfort. Some of those providers help online.

Making a Plan for a Bleed at Home

With your dog at home, a written plan can make a hard night more manageable. Here's what families often put in theirs:

• The number of a 24-hour emergency clinic, or, if one is far away, the nearest vet who can see your dog right away.
• Any vet who has seen your dog, and their after-hours number if they have one.
• How you'd lift and carry your dog, and whether anyone could help or drive.
• The number for an in-home euthanasia vet or hospice team, and whether they take urgent after-hours calls.
• What you'd want to happen during a bleed, going in for care or saying goodbye, if you're able to decide that ahead of time.

Our directory lists in-home euthanasia vets who come to your home. Our guides to deciding when it's time to say goodbye to a dog and choosing between a goodbye at home or at a clinic walk through the decision and the day.

If Your Dog Died From Hemangiosarcoma

We're so sorry. For some dogs, the bleed itself is the first sign of hemangiosarcoma.

Some families said goodbye in an emergency room soon after hearing the word. Others said goodbye during surgery, or lost their dog at home before anyone knew. Some had days or weeks at home on comfort care, and some chose surgery and had time together after. Each of them is grieving a dog they love. If a vet saw your dog, they may be able to talk through what they found.

If aftercare is still being arranged, some families choose right away, and some want time to decide. Questions families often ask the clinic or crematory:

• Can I spend some time with my dog first?
• If I'd like a necropsy, how long do I have to decide, and what does it cost?
• What are my cremation and burial options, and what does each one include?
• Could I have a keepsake, like a paw print or a clip of fur?

Our aftercare and pet memorial resources cover cremation, burial, and keepsakes in more depth. If you'd like someone to talk to about what happened, our directory lists pet loss grief counselors, including some who meet online.

If your dog died suddenly, we wrote our sudden loss of a pet resources for you, with help for the first hours and days.

Caring for a Dog With Hemangiosarcoma, Whatever Comes Next

Hemangiosarcoma in dogs often arrives all at once: a collapse, a scan, a word most families have never heard, and choices about surgery, comfort care, and euthanasia that can come fast.

If your dog is with you and there's time, write down the bleed plan above and keep it by the phone. You can ask for an itemized estimate for any path, at any point. If your dog has died, we're so sorry, and the support below is here for whatever comes after.

On this topic

Keep reading

• How to Know When to Put Your Dog Down →
• Dog Cancer Diagnosis: Your Complete Guide to What Comes Next →
• How Pet Hospice Works, and When It’s the Right Choice →
• Pet Pain Management at End of Life: Complete Options Guide →