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Hemangiosarcoma in Cats

Hemangiosarcoma can be internal or external.

Hemangiosarcoma is a type of cancer that originates in the blood vessels. That means that it can be found anywhere in the body. However, in cats, it is most likely to appear in the spleen, liver, heart, or skin.

Visceral Hemangiosarcoma in Cats

Visceral hemangiosarcoma means that the cancer is internal. In cats, the spleen and liver are the most common places for a hemangiosarcoma tumor to develop and grow.

Many times, cats with visceral hemangiosarcoma look and act normal and then suffer an episode of collapse or sudden death. That's because the tumor, which affects blood vessels, has ruptured and the cat is bleeding internally. If the problem is diagnosed quickly enough, emergency surgery usually needs to be performed to remove the tumor.

Most of the time, cancerous cells have spread throughout the body through the circulatory system by the time the condition is diagnosed. That means that, even if surgery is done to remove the primary, actively bleeding tumor, cats usually become sick from the development of tumors in other areas, like the heart and lungs, shortly afterward.

If there are any symptoms before collapse in cats with visceral hemangiosarcoma, they can include:

  • Weight loss
  • Enlarged abdomen
  • Cough
  • Lethargy
  • Decreased appetite
  • Panting
  • Pale gums
  • Weakness

This condition is far more common in dogs than cats.

Cutaneous Hemangiosarcoma in Cats

About half of cats that are diagnosed with hemangiosarcoma have the skin, or cutaneous, form. This type of cancer may either be on top of the skin, where it usually looks like a raised red or purple bump, or underneath the skin, where it usually feels like a soft, movable lump. If it's on top of the skin, it might bleed easily.

Cats with short hair and light skin might be more prone to developing cutaneous hemangiosarcoma than other cats, so protecting cats from sun exposure might decrease their risk of developing this condition.

Cats that are diagnosed with cutaneous hemangiosarcoma should have complete blood work and chest and abdominal x-rays done to look for any evidence that the cancer has spread internally.

Diagnosis of Hemangiosarcoma in Cats

A diagnosis of hemangiosarcoma is made when cells from the tumor are evaluated microscopically. This is usually done in the form of a biopsy once the tumor has been removed. The tumor can be sent to a veterinary pathologist for examination, diagnosis, and staging. Additionally, the pathologist can evaluate the margins of removed skin tumors to help determine whether the entire tumor was successfully removed or whether cancer cells are likely to have remained at the surgical site.

For skin hemangiosarcoma, the initial diagnosis is sometimes made by a primary veterinarian through the results of a fine needle aspirate (FNA), during which cells are removed from the tumor by a needle and examined under a microscope. This can help the veterinarian determine that the tumor should be surgically removed right away.

Treatment of Hemangiosarcoma in Cats

As stated above, visceral hemangiosarcoma is first treated by surgically removing as much of the tumor as possible. After that, chemotherapy might help slow down the cancer's spread, but average survival times for cats with internal hemangiosarcoma are short.

Cutaneous hemangiosarcoma is treated by surgical removal of the tumor(s), including as much of the surrounding tissue as possible. Radiation therapy and/or chemotherapy may be recommended after the initial surgery.

Some cats with a solitary hemangiosarcoma tumor on the skin can be treated with surgery alone. Each individual case is different, but once cutaneous hemangiosarcoma is diagnosed and removed from a cat, the owner should be diligent about looking for new skin tumors.

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