Paraneoplastic Syndromes in Cats

A neoplasm is another word for a tumor and para is a Greek word typically used to denote something is near another thing. Paraneoplastic has a literal meaning, therefore, of “near a tumor”. Paraneoplastic syndromes can affect a variety of areas of your cat and can occur before or in connection with symptoms of the nearby tumor.

Paraneoplastic syndrome in cats refers to a series of side effects, damage or other cellular or structural changes that occur in tissues near or surrounding tumors.

The symptoms of paraneoplastic syndrome in your cat will vary widely depending on the type and location of tumor. Symptoms will also vary in severity depending on progression and growth of the tumor. Signs of paraneoplastic syndromes include:

• Pustules or open wounds on skin
• Shiny and hairless patches of skin, especially on stomach area
• Open or weeping wounds around toes
• Rash
• Alopecia (hair loss)
• Loss of pigment on paws or other areas
• Weight loss 
• Loss of appetite

The underlying cause of paraneoplastic syndromes is various bodily tumors, both cancerous and non-cancerous. While the exact mechanisms of paraneoplastic syndromes are unknown, most veterinarians and researchers agree that secretions from tumors can affect nearby tissues and cause damage and degeneration. These secretions may stimulate an immune response in these tissues, causing the symptoms. Malignant, or cancerous, tumors will often release substances that cause white blood cells to inappropriately attack the tissues. Non-malignant tumors typically release hormones that cause abnormal growth or other changes.

Diagnosis of paraneoplastic syndromes in your cat will begin with your veterinarian ruling out other, similar conditions.  Skin scrapings of any sores and other tissue samples may be sent off by your vet to an independent laboratory for analysis. A complete blood panel will also rule out infection or systemic diseases. Blood thyroid tests will rule out hypo- or hyperthyroidism, which will often present with similar symptoms.

A thorough physical examination of your cat, along with a complete history of the progression of symptoms, will also be essential in the diagnosis of paraneoplastic syndrome. You should provide your veterinarian with approximate dates of when symptoms first appeared, along with any changes in the condition. If your cat or your cat’s relatives have a known history of cancer, this will also be important information.

Since diagnosis of these syndromes will depend on identifying the presence of one or more tumors, your veterinarian will also request various imaging tests. These may range from x-rays to MRI or CT scans or ultrasound, depending on the suspected location of the tumor. For many of these types of imaging procedures, your cat will need to be at least mildly sedated and possibly anesthetized.  

Having your cat calm and quiet will produce the best images and will allow your vet the best look into the body of your pet. Anesthesia comes with inherent risks. Prior to being anesthetized your vet will run bloodwork and listen to your cat’s heart to ensure it is healthy enough to undergo the procedure. If tumors are located, your vet may also choose to take a sample of the tumor using a fine needle biopsy.

Treatment of paraneoplastic syndromes in your cat will begin with supporting your cat’s overall health and treating any urgent symptoms. Open sores, weight loss and general lethargy will be addressed with medications and wound care, which will improve the strength of your cat’s immune system and overall bodily health.

The next step in treatment will typically involve addressing the underlying tumor or tumors. Depending on the location of the tumor and whether it is cancerous, your vet has multiple options. For cancerous and noncancerous tumors that have good surgical accessibility, removing the tumor is always the preferred route.  

In the event of a cancerous tumor that is not in an operable location, your vet may choose to use chemotherapy or radiation to reduce the size of the tumor. The symptoms of paraneoplastic syndrome will often lessen greatly in response to these treatments, at least temporarily, as the tumor is in decline. Chemotherapy and radiation have a variety of side effects, although your veterinarian may be able to prescribe medications to lessen these effects.

Long-term prognosis for complete recovery will be individual to each specific case. In most instances, paraneoplastic syndrome can be individually managed with tumor removal and medication. You will need to strictly adhere to any post-surgical instructions and be sure to administer all medications in a timely manner. Symptoms will begin to resolve immediately upon removal of the underlying condition. Your cat will need regular veterinarian visits to ensure no additional tumors occur.  In the case of total excision, your cat has a good prognosis for quality and length of life.