Cancer of the Blood Vessel Cells in Cats

Cancer of the blood vessel does not tend to metastasize, or spread throughout other organs in the body. This type of cancer does, however, tend to grow very large and regrow, even after removal. The tumors will create fingerlike protrusions that can infiltrate between layers of muscle or other tissues. Because of its invasive nature, the tumor that results from cancer of the blood vessels can spread aggressively until it blocks the surrounding blood vessels or nearby major organs.

Cancer of the blood vessel cells is a cancer originating from pericyte cells that support your cat’s blood vessels. Also known as hemangiopericytoma, cancer of the blood vessels occurs more frequently in dogs but can also affect your cat when pericyte cells cease their normal function and instead, form a cancerous tumor. Normally, pericyte cells are supportive cells that are located all over the body. Unlike other cells in the body, pericyte cells never adapted a specific function when your cat was forming in the embryonic stage. Pericyte cells are essentially “on call” throughout your pet’s lifetime and can form into a variety of muscular or tissue cells as the need arises.

It’s important to note that symptoms can be very slow to develop with cancer of the blood vessels. While they may be difficult at first to detect, there are very common signs to watch for.

• Small lumps or nodules appear on your cat
• Lumps tend to be non-painful in nature
• Lumps will often occur on limbs
• Lumps will occasionally occur on trunk, or body of your cat
• Lumps can grow or spread into larger growths if left untreated

As in the case of many types of cancer, the exact cause of cancer of the blood vessels in cats is unknown. The condition occurs when the pericyte cells divide improperly, which causes chromosome damage in the cell itself. Cancer may have genetic or environmental influences.

As with many serious illnesses, your veterinarian will need a thorough medical and physical history of your cat in order to provide an accurate diagnosis. If possible, you should provide your veterinarian with any cancer history in your cat’s relatives. You should also thoroughly document the size of the lump on your cat and, if possible, the approximate rate of growth. This will assist your veterinarian in determining how aggressive the condition is in your cat.

Next, your vet may aspirate the lump to rule out less serious conditions such as subcutaneous cysts, fatty cysts and other harmless growths. Aspiration involves inserting a needle into the growth and extracting any available fluid. Your vet may also biopsy the lump through this method. This will generally be a painless procedure and will not require your cat to undergo anesthesia. 

Depending on the results of the aspiration, your vet may order additional imaging procedures. Pictures, such as x-rays, or more commonly MRI or CT Scans, will indicate whether the cancer has metastasized to any other major organs. Once a confirmed diagnosis of cancer of the blood vessels is made, your vet may refer your cat to an oncologist for treatment.

There are several different treatment options your veterinarian may recommend for your cat. These options will depend on factors such as size and growth rate of the tumor and whether the cancer has spread to surrounding tissues.

Surgical Removal

When possible, surgical removal of the tumor is the preferred method of treatment for your cat. Your cat will have to undergo anesthesia for this procedure, which has its own cardiovascular and respiratory risk. Your veterinarian will then use previous scans and surgical exploration to remove the tumor. Given the potential for regrowth, it is important that your vet remove as much tissue as safely possible, in order to obtain clean margins, or an area surrounding the tumor that contains no cancer cells.

Radiation and Chemotherapy

In some cases, surgery will be difficult, or, upon beginning the surgical procedure, your vet will see that the cancer has spread significantly. This is especially true with these types of tumors given their finger-like protrusions that will often wrap between and around various surrounding muscles or organs. In this case, you veterinarian may recommend radiation or chemotherapy, either in connection with surgery or as an independent procedure. Both radiation therapy and chemotherapy carry side effects that can be partially alleviated with various medications. 

Recovery of your cat after treatment for cancer of the blood vessels will depend on the method of treatment and whether all of the cancer was removed. With chemotherapy or radiation, the spread of the disease may be halted or slowed. In some cases, these treatments may also cause the tumor to shrink to a size that would allow surgical intervention.

With surgery, it will be important to follow all postoperative instructions from your vet so that your cat has the time and energy needed to heal completely. Your cat will need to be kept quiet and away from other household pets. Your cat may also need medication in order to combat any potential infection.

If complete removal of the tumor is accomplished, your cat has a good chance at a normal life. Your cat should be closely monitored, at least yearly, by a vet in order to check for any regrowth or the presence of new tumors.