Health & Diseases

Hemangiosarcoma in Dogs: Symptoms, Treatment, and Prognosis

Hemangiosarcoma (HSA) is a highly malignant tumor of blood vessel walls (endothelial cells). It grows quickly, metastasizes early, and is often only discovered when a tumor-related internal hemorrhage—often from a ruptured spleen or a heart atrial tumor—triggers a life-threatening emergency.

Hemangiosarcoma in Dogs: Symptoms, Treatment, and Prognosis

What is hemangiosarcoma in dogs?

Hemangiosarcoma (HSA) is a highly malignant tumor of the blood vessel walls (endothelial cells). It grows rapidly, metastasizes early, and is often not detected until tumor-related internal bleeding—frequently from a ruptured spleen or an atrial tumor—triggers a life-threatening emergency.

Hemangiosarcoma is one of the most common malignant tumors in dogs. It primarily affects older dogs of medium to large breeds—Golden Retrievers, Labrador Retrievers, German Shepherds, and Boxers, in particular, have a higher incidence.

Background + Scientific Context

Schultheiss (2004, Journal of Veterinary Diagnostic Investigation, PubMed 15053370) analyzed retrograde visceral and non-visceral hemangiosarcomas and hemangiomas in companion animals: Visceral HSA in dogs most commonly affects the spleen (>50% of cases), followed by the right atrium and the liver. Non-visceral cutaneous HSA has a significantly better prognosis than visceral forms. Diagnosis is made histopathologically—imaging techniques (ultrasound, X-ray) reveal masses but do not confirm the diagnosis.

Thamm (2013, *Withrow & MacEwen's Small Animal Clinical Oncology*, Elsevier) provided a comprehensive description of the biology and treatment of HSA: HSA tends to metastasize hematogenously at an early stage—the lungs, liver, omentum, and brain are common sites of metastasis. Even after surgical resection of an isolated splenic HSA lesion, the median survival time without chemotherapy is approximately 1–2 months; with adjuvant doxorubicin chemotherapy, it is 4–6 months. The overall prognosis is poor.

Batschinski et al. (2018, Veterinary and Comparative Oncology, PubMed 29115027) compared surgical treatment alone versus surgery plus doxorubicin in visceral HSA: The combination therapy significantly prolonged median survival (surgery alone: 19 days; surgery + doxorubicin: 133 days). Important: Despite treatment, the majority of dogs died within 6 months due to tumor progression or metastases. The decision for or against chemotherapy involves weighing quality of life, life expectancy, and the burden on the patient.

Vitomalia-Position

Hemangiosarcoma forces dog owners to make one of the most difficult decisions: emergency surgery followed by chemotherapy—or palliative care? There is no wrong choice. What matters is making this decision consciously and with full information—with a veterinarian who clearly communicates the prognosis and doesn’t sugarcoat it.

When does hemangiosarcoma become a concern?

  • In the case of an acute collapse episode in an older large-breed dog: internal bleeding, suspected HSA
  • If an ultrasound reveals a mass in the spleen or atrium
  • If you have pale mucous membranes, weakness, or a distended abdomen: possible spleen rupture
  • Breeds known to have a higher incidence: Golden Retrievers, Labradors, German Shepherds
  • Upon diagnosis: decision on emergency surgery, follow-up care, chemotherapy, palliative care

Practical application

HSA — Locations and Prognosis:

Localization Frequency Median survival time
Spleen >50% of cases 1–2 months (surgery alone) / 4–6 months (surgery + chemotherapy)
Right atrium ~25% 1–4 months
Liver ~25% Poor, often inoperable
Cutaneous form (skin) Rare Better — can be curative

Diagnostic steps: 1. Abdominal ultrasound + echocardiography if suspected 2. Chest X-ray: To rule out lung metastases 3. Complete blood count: Anemia, fragmentocytes (indicative of DIC) 4. Postoperative histopathology for confirmation

Common Mistakes & Myths

  • “Everything is fine after the surgery.” Surgical resection is not a curative procedure for visceral HSA—micrometastases are statistically almost always already present.
  • “My dog didn’t have any symptoms.” HSA often grows without symptoms until it ruptures. Regular preventive ultrasound exams for high-risk breeds can lead to earlier detection.
  • “Chemotherapy is always a good option.” The decision depends on age, overall health, the extent of metastasis, and quality of life. In cases of extensive metastasis, palliative care may be the better option.

Current State of Research (2026)

The median survival time for visceral HSA has hardly changed over the past two decades despite improved chemotherapy regimens—the biological aggressiveness of the tumor limits therapeutic progress. Immunotherapeutic approaches (antibodies, tumor vaccines) and tyrosine kinase inhibitors are being investigated in veterinary oncology. Initial studies with propranolol as an adjunct to chemotherapy show a slight prolongation of survival—data are still limited.

Frequently Asked Questions

How long do dogs live after being diagnosed with hemangiosarcoma?

Depending on the location and treatment: Visceral HSA (spleen) without treatment: days to weeks; with surgery alone: approx. 1–2 months; with surgery and doxorubicin chemotherapy: approx. 4–6 months. Cutaneous HSA without visceral involvement can be treated curatively. It is important in every case to have a clear discussion with the veterinarian about the prognosis and quality of life.

Which dogs are at the highest risk for hemangiosarcoma?

Older dogs (>8 years) of large breeds—particularly Golden Retrievers, Labrador Retrievers, German Shepherds, Boxers, and Dobermans. Male dogs may be affected slightly more often than females. The genetic predisposition in Golden Retrievers is well documented.

Are there any early symptoms of hemangiosarcoma?

Often not—HSA often develops without symptoms for a long time. Nonspecific early signs include a decline in performance, occasional weakness, and a general feeling of being unwell. Acute symptoms (collapse, pale mucous membranes, distended abdomen) often do not appear until the tumor ruptures and causes internal bleeding. Regular preventive ultrasounds in high-risk breeds can enable earlier detection.

Related terms

Sources & Further Reading

  1. Schultheiss, P. C. (2004). A retrospective study of visceral and nonvisceral hemangiosarcoma and hemangiomas in domestic animals. Journal of Veterinary Diagnostic Investigation, 16(6), 522–526. https://pubmed.ncbi.nlm.nih.gov/15053370/

  2. Thamm, D. H. (2013). Miscellaneous tumors. In S. J. Withrow, D. M. Vail, & R. L. Page (Eds.), Withrow & MacEwen's Small Animal Clinical Oncology (5th ed., pp. 679–688). Elsevier. ISBN 9781437707236.

  3. Batschinski, K., Nobre, A., Vargas-Mendez, E., Tedardi, M. V., Cirillo, J. V., Ubukata, R., Castanheira, T. L., & Dagli, M. L. Z. (2018). Canine visceral hemangiosarcoma treated with surgery alone or surgery and doxorubicin. Veterinary and Comparative Oncology, 16(1), E169–E175. https://pubmed.ncbi.nlm.nih.gov/29115027/

Wissenschaftliche Einordnung

Schultheiss (2004, Journal of Veterinary Diagnostic Investigation, PubMed 15053370) analyzed retrogressive visceral and non-visceral hemangiosarcomas and hemangiomas in domestic animals: Canine visceral HSA most commonly affects the spleen (>50% of cases), followed by the right atrium and liver. Non-visceral cutaneous HSA has a significantly better prognosis than visceral forms. Diagnosis is histopathological — imaging techniques (ultrasound, X-ray) show space-occupying lesions but do not confirm the diagnosis.

Thamm (2013, Withrow & MacEwen's Small Animal Clinical Oncology, Elsevier) comprehensively described the biology and therapy of HSA: HSA tends to metastasize hematogenously early – the lungs, liver, omentum, and brain are common sites of metastasis. Even after surgical resection of an isolated splenic HSA lesion, the median survival time without chemotherapy is approximately 1–2 months; with adjuvant doxorubicin chemotherapy, it is 4–6 months. The overall prognosis is unfavorable.

Batschinski et al. (2018, Veterinary and Comparative Oncology, PubMed 29115027) compared surgical treatment alone vs. surgery plus doxorubicin for visceral HSA: Combined treatment significantly extended median survival (surgery alone: 19 days; surgery + doxorubicin: 133 days). Important: The majority of dogs died within 6 months despite treatment due to tumor progression or metastasis. The decision for or against chemotherapy is a balance between quality of life, life expectancy, and patient burden.