Hemangiosarcoma (Splenic or Visceral) in Cats

Published on
Last updated on
3 min read

Key takeaways

Hemangiosarcoma is cancer of the blood vessel walls. Visceral hemangiosarcoma is when this cancer occurs internally. 

  • Hemangiosarcoma is a highly aggressive and metastatic cancer type characterized by fragile, blood-filled lesions in the organs
  • Most commonly found in the spleen, heart, lungs, and liver, but can occur anywhere in the body
  • Visceral hemangiosarcomas are most often detected after a tumor has ruptured, resulting in symptoms of internal bleeding, including weakness, collapse, pale gums, rapid breathing, and appetite loss
  • Diagnostics include blood tests, medical imaging, and tumor biopsies
  • Treatment is primarily surgery to remove the tumor or whole organ followed by chemotherapy
  • The prognosis is very poor and euthanasia is a common outcome following diagnosis since survival times are often less than a couple of months
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A closer look: Hemangiosarcoma (Splenic or Visceral) in Cats

Hemangiosarcoma is an aggressive cancer of the blood vessels. Hemangiosarcoma tumors can develop anywhere in the body as the cancer cells collect in different blood vessels.

Symptoms of hemangiosarcoma often go undetected until severe internal bleeding occurs. Sudden death may be the only apparent symptom. Prognosis is poor and in a best-case scenario treatment extends life expectancy by approximately 3 months.

Risk factors

Hemangiosarcoma is a rare form of tumor in cats. The underlying disease process is not well understood so it is difficult to identify individual risk factors. This form of cancer is seen more frequently in older cats and those with short hair.

Possible causes

The cause of this cancer is unknown. It originates in the bone marrow as these cells develop to create new blood vessels. As with all forms of cancer, environmental and genetic risk factors are likely.

Main symptoms

The primary symptom is tumor formation within the body which is fragile and blood filled. Symptoms are rarely caught prior to the tumor bursting.

Testing and diagnosis

After a physical examination and medical history, diagnostic imaging and biopsy confirm diagnosis of hemangiosarcoma.

Steps to Recovery

Once a visceral hemangiosarcoma is confirmed, treatment prioritizes stabilization. If a rupture has occurred, the bleeding must be addressed and symptom management including IV fluids and blood transfusions are necessary.

To treat the sarcoma, the main option is surgery, either removal of the tumor and surrounding tissue or full removal of the organ where possible. In many cases, euthanasia is recommended during surgery due to the severity of disease. Surgery may be followed by chemotherapy (especially in cases of metastasis) to attempt to reduce the spread and lower the risk of recurrence.

The prognosis for visceral hemangiosarcoma is very poor. It is highly metastatic and is usually caught only after a tumor ruptures. Treatment may extend life expectancy by a few months but is mostly palliative.


It is not currently known what causes internal hemangiosarcomas and therefore prevention is difficult. Monitoring of overall pet health and signs of abdominal distress and internal bleeding are always beneficial.

Visceral hemangiosarcoma is not contagious.

Is Hemangiosarcoma (Splenic or Visceral) in Cats common?

Visceral hemangiosarcoma is rare in cats.

Typical Treatment

  • Diagnostic imaging
  • Chemotherapy
  • Palliative care
  • Stabilization care


PetMD Editorial - Writing for PetMD
Wendy Brooks, DVM, DABVP - Writing for Veterinary Partner
Wendy Brooks, DVM, DABVP - Writing for Veterinary Partner
Dr. Kimberly Cronin - Writing for PetPlace

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