Common Types of Oral Tumors in Dogs and Cats

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Common Types of Oral Tumors in Dogs and Cats

Oral neoplasia, also known as oral tumors, can occur in both dogs and cats. They are abnormal growths of cells within the oral cavity, which includes the lips, gums, tongue, hard palate, and the back of the throat. These tumors can be benign (non-cancerous) or malignant (cancerous). Malignant tumors are typically defined as tumors that have the ability to metastasize (spread to distant sites in the body) or have local invasion. Local invasion means that the tumor is like the head of an octopus, and there are tumor cells that spread deep into the surrounding tissue like the tentacles of an octopus. Tumors that have local invasion tend to come back after surgical removal. While there are many kinds of oral growths seen in veterinary medicine, this blog will cover some of the most common types of oral tumors in dogs and cats. Most oral tumors in dogs are benign tumors. Cats get fewer oral tumors that dogs, but the majority of oral tumors in cats are malignant. 


Common Types of Oral Neoplasia in Dogs


The following types of oral tumors are common in canine patients.


Peripheral odontogenic fibroma (POF, previously called “epulis”)

POF is the most common benign oral tumor in dogs, arising from the periodontal ligament or gingival tissues. These tumors, although non-cancerous, can grow to significant size and can cause local discomfort. Affected dogs may have multiple tumors.


Canine acanthomatous ameloblastoma

Canine acanthomatous ameloblastoma is another common benign oral tumor in dogs. This may resemble POF, and is still benign, but can invade local bone and require more aggressive surgery to remove completely.


Viral papilloma

These are benign oral tumors that appear as small, raised, pale “cauliflower-like” masses in any part of the oral cavity. Affected dogs may have from one to hundreds of masses. Unlike other oral tumors, these tumors are caused by a virus, and are contagious between dogs, but not to other species. Fortunately, most of these tumors spontaneously resolve when the immune system fights off the virus that causes them. 


Malignant Melanoma

Malignant Melanoma is the most common form of malignant oral tumor in dogs. Oral melanoma may appear as a darkly pigmented mass, may be gray in color, or may be pink. They can occur on any site in the oral cavity, are more aggressive in nature, and are highly metastatic, which means that they can spread to other tissues such as the lungs and lymph nodes, and also have local invasion.



Fibrosarcoma is another common type of malignant tumor that can occur in the mouth of dogs and may arise from the connective tissues of the gums and bones. These tumors are typically slow to metastasize, but have local invasion deep into the surrounding tissues.



Osteosarcoma is a malignant oral tumor that arises from the bones. These tumors are typically slow to metastasize, which is different than osteosarcomas that develop in other parts of the body, but have local invasion.


Squamous Cell Carcinoma

Squamous Cell Carcinoma is a malignant oral tumor. It can appear on the gums, cheeks/lips, tongue, or tonsils. These tumors may be painful for the pet. These tumors may metastasize and they have local invasion.


Common Types of Oral Neoplasia in Cats


The following types of oral tumors are common in feline patients.


Squamous Cell Carcinoma

Squamous Cell Carcinoma is the most common type of tumor in the oral cavity of cats. It often results in oral pain. These tumors are often not detected until they have become more advanced. They have aggressive local invasion and the potential to metastasize.


Pyogenic Granulomas

Pyogenic granulomas are a type of benign oral growth that usually result from irritation of the gum tissue. The most common cause of this is when a large chewing tooth has been extracted, and the opposing tooth is causing chronic irritation of the gum tissue. Treatment is removing the tooth that is causing the problem. The granuloma may spontaneously resolve, or may need to be surgically removed. 


Eosinophilic granuloma

Eosinophilic granuloma is a tumor-like mass that can occur on the lip or in the mouth. It is an inflammatory lesion that may be caused by allergies or other inflammatory conditions. Because they are inflammatory lesions, these are treated with medications and often dietary therapy.


Osteosarcoma, Fibrosarcoma, and Melanoma

These tumors are less common in cats, and when they occur, they are similar to those seen in dogs.


Signs of Oral Tumors in Dogs and Cats


Clinical signs of oral tumors in dogs and cats can vary, but may include symptoms like bad breath, drooling, difficulty eating or swallowing, and even bleeding from the mouth. Some pets with oral tumors do not show any abnormal signs until the tumor is very advanced. Oral tumors can be diagnosed through a combination of physical examination, biopsy, and imaging studies like CT scans or dental radiographs

The treatment for oral tumors is dependent on the type of tumor, if it’s malignant or benign, its location, and any additional underlying health complications your pet may have. Treatment options may include surgical removal, radiation therapy, chemotherapy, other medical treatment, or in some cases (like with viral papillomas) no treatment at all. Early detection, diagnosis, and intervention are crucial for a better prognosis and improved quality of life.


Photo by Petfoto from Pixabay

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