Oral Tumors in Pets

Tumors in the mouth are common in dogs and cats, but may not be initially obvious to the owner. Tumors are classified as benign or malignant. There are also other causes of swelling of tissues in the mouth – gingival hyperplasia (generalized overgrowth of the gum tissue) is common in dogs and occasionally cats, and is not a tumor. Other non-tumorous causes of

swelling of oral tissues include local infection or collection of saliva from a damaged salivary gland. Benign tumors do not spread to other parts of the body, and generally grow more slowly than malignant tumors. Malignant tumors (cancer) invade the tissues adjacent to the tumor and may spread to other parts of the body. Sometimes even aggressive treatment is not successful.

Fig 1. Malignant oral tumor.                            Fig 2. Benign oral tumor.


While the visual appearance of an oral growth (its surface color and texture, the contour of the tumor and its size and location) can often give clues as to its identity, confirmation of the diagnosis (and thus an accurate prognosis and identification of appropriate treatment) requires biopsy. All oral growths should be investigated. A “wait and see” approach is not satisfactory.

Biopsy may be incisional (taking a small portion for microscopic examination, with no attempt to remove all of the swelling) or excisional (surgery to remove the tumor completely). The biopsied tissue is sent to a pathologist. If the veterinarian feels an abnormality of one of the lymph nodes in the neck, biopsy or needle aspiration of the abnormal lymph node may be recommended.

For most oral tumors (benign and malignant), surgical removal offers the best chance of cure. Surgery may need to be radical (removal of part or all of a jaw, including teeth and bone, for example). Though dogs tolerate radical surgery very well, cats may take a little longer than dogs to recover full function. 

Because there are so many types of oral tumors that can occur in dogs and cats, each with a different prognosis, management by an AVDC veterinary dental specialist or oncologist is recommended. Your regular veterinarian may take a biopsy and then refer the case to a specialist.

What can pet owners do to be pro-active about oral tumors? The key is early detection of the growth. Owners that are in the (highly recommended!) habit of brushing their pet’s teeth every day are likely to note changes in the mouth earlier. For owners not brushing daily, a weekly oral inspection by the owner is recommended, in addition to regular examination by your veterinarian. When a swelling in the mouth is noted, seek the services of your veterinarian or a veterinary dentist without delay.