Oral Masses in Cats

Published Dec. 2, 2022

What Are Oral Masses in Cats?

An oral mass is any abnormal growth or swelling in the mouth or surrounding tissues. This includes the gums, tongue, oropharynx (part of the throat at the back of the mouth), larynx (area of the throat containing the vocal cords), glottis (the primary valve between the lungs and the mouth), epiglottis (the flap that covers the trachea during swallowing), hard and soft palates (the roof of the mouth), cheeks, lips, tonsils, and the glands, lymph nodes, and bones of the mouth.

An oral mass in a cat does not always mean cancer. The mass may be caused by infection, inflammation, an immune system disorder, trauma, or the formation of abnormally dividing cells (neoplasia). However, if left untreated, even a benign oral mass in a cat can become fatal.

Early detection and diagnosis of oral masses is key in reducing the morbidity and mortality of feline patients. It’s important that you take your cat to their veterinarian yearly, so they can do a thorough examination of your cat’s mouth to identify any diseases and start treatment early in the disease process. Regular dental hygiene at home and annual dental cleanings can also lead to early diagnosis of an oral mass.

Types of Oral Masses in Cats

There are many different types of oral masses in cats. Some of the most common include:

Tumor: A tumor is a mass of tissue generated by abnormally dividing cells that no longer respond to normal tissue-organizing stimuli. Tumors may be benign (noncancerous, slow-growing and do not spread) or malignant (cancerous, fast-growing and usually spread to lymph nodes and/or organs). Neoplasia occurs frequently in cats, with most tumors being cancerous. Benign tumors are very rare, but like malignant tumors, they can be very infiltrating and destroy the surrounding tissues.
Non-neoplastic growths/swellings: There are a few immune system disorders and many inflammatory, infectious, and traumatic processes that result in secondary soft tissue and bony oral masses in cats.

Malignant Oral Tumors (Cancer)

Squamous cell carcinoma (SCC) is the most common oral cancer in cats. SCC commonly occurs on the tongue, pharynx, or lower and upper jawbone.
Fibrosarcoma (FSA) is the second most common oral cancer in cats. These cancers tend to be locally invasive to the gums and bones of the mouth.
Other less common feline oral cancers include lymphosarcoma, osteosarcoma, and melanoma.

Benign Oral Tumors (Noncancer)

Osteoma is a very rare benign tumor of the bone, usually involving the mandible in cats.
Odontogenic tumors are also rare and originate from the structure of and around teeth.

Symptoms of Oral Masses in Cats

In addition to the obvious (or not-so-obvious) mass, there are many other symptoms you might notice when your cat has an oral mass. Some of these include:

Excessive salivation
Blood in the mouth or blood-tinged saliva
Decreased or loss of appetite
Difficulty eating or apprehending food
Resistance to dry food, but will eat wet food
Pawing at the mouth
Pain when eating
Pain on palpation of the mouth
Foul odor from the mouth (halitosis)
Abnormal tongue movements
Loose teeth
Loud breathing
Gagging
Lethargy
Weight loss

Causes of Oral Masses in Cats

Depending on the type of oral mass, the cause may vary. The exact cause of feline oral cancer is unknown. However, like humans with cancer, feline oral cancers are typically caused by a combination of genetic and environmental influences. There are risk factors that are thought to significantly increase the risk of developing squamous cell carcinoma, such as flea collars, high canned-food consumption (including tuna), and secondhand cigarette smoke. Excessive exposure to sunlight can also contribute to the development of skin squamous cell carcinomas on and around the outside of the mouth.

Periodontal disease, an infection and inflammation of the gums and supporting structures surrounding the teeth, is the most common disease in small animals. If left untreated it can result in many types of oral masses in cats. Trauma to the head and mouth can cause swellings in and around the mouth as well.

A few immune system disorders can also cause oral masses. Stomatitis is inflammation in the mouth and is thought to be determined by multiple factors. It is associated with viral, bacterial, and immune-mediated causes. Another disease, eosinophilic granuloma complex (EGC), includes skin lesions on the lips and/or in the mouth, and is thought to be associated with allergies. Lastly, allergic reactions can cause swellings of the mouth as well.

How Veterinarians Diagnose Oral Masses in Cats

A vet may perform diagnostic tests to determine the type of mass in a cat’s mouth, all of which require general anesthesia. Some of these tests include biopsy, a fine needle aspiration (FNA), dental or skull radiographs (x-rays), periodontal probing, MRI, and CT scans. Bloodwork done prior to these tests may also be helpful in a diagnosis.

Treatment of Oral Masses in Cats

Early radical surgical resection (removal of the entire tumor as well as some healthy tissue around it, called the margin) is the treatment of choice for oral tumors, both benign and malignant, in cats.

The surgical procedures used for cancers, osteomyelitis, and mandibular fractures for which primary repair is not possible or has failed are called mandibulectomy and maxillectomy. These procedures remove the lower or upper jaw, respectively.

Some surgeries may not be curative alone, and the cat may require adjunct treatment such as chemotherapy and/or radiation. Cats that have an oral mass that has destroyed too much of the surrounding tissue (locally invasive) or encompasses multiple structures of the mouth and/or has spread to other areas (metastasized), or that have other comorbidities making anesthesia too challenging, would not be a good candidate for surgery.

Oral masses due to periodontal disease will need to be treated with antibiotics, anti-inflammatories, dental cleanings with or without teeth extractions, and sometimes full-mouth teeth extractions. Masses due to trauma will require surgery, medications, and manual reductions of the luxation. Treatment for immune system disorders may require steroids, immunomodulatory drugs, full-mouth extractions, and antihistamines.

Recovery and Management of Oral Masses in Cats

Prognosis depends heavily on the type of oral mass and treatment options available.

Prevention of Oral Masses in Cats

Unfortunately, there is no way to prevent oral cancers in cats. It’s important to get routine annual exams and annual sedated dental cleanings to catch oral cancers early in the disease process. Annual dental cleanings with dental radiographs also support good oral health, which is very important, since it can help prevent many types of oral masses associated with periodontal disease and its secondary inflammatory processes. Taking this into account and incorporating good dental hygiene practices at home will allow for better treatment options and a better prognosis for your cat.

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