Oral Tumors in Dogs: Causes, Symptoms, Risks, and Diagnosis

Oral tumors in dogs are abnormal masses in the mouth. Oral growths are benign or malignant and stem from various tissues, most commonly from the gums.

The most frequently reported oral tumors in dogs are malignant melanoma (MM), squamous cell carcinoma (SCC), fibrosarcoma (FSA), anacthomatous ameloblastoma (AA), odontogenic tumors, and osteosarcoma (OSA).

The causes of oral tumors include a genetic component among certain dog breeds, DNA mutations, and environmental factors, such as UV light and exposure to cancer-causing carcinogens.

A mouth tumor in dogs is prevalent among senior male dogs. Predisposed breeds are Poodles, Shih Tzus, and German Shepherds.

Symptoms of a tumor on dog lip or mouth include excessive drooling, bloody saliva, bad breath, face pawing, facial asymmetry, trouble eating, and weight loss.

The risks of oral tumors are ulceration, mouth infections, tooth loss, malnutrition due to trouble eating, and metastases from cancerous tumors.

Diagnosing dog oral cancer involves fine needle aspiration and biopsy. Oral tumors in dogs are treated with surgery, radiation, chemotherapy, or vaccines.

CBD is an excellent addition to the multimodal cancer on dog lip or mouth treatment plan. The natural hemp extract is suitable for dogs of all ages and is safe to combine with mainstream anti-cancer treatments.

What is Oral Tumors in Dogs?

Oral tumors in dogs are abnormal growths in the mouth. Masses in the mouth stem from many locations, including the gums (gingiva), periodontal structures, tongue, and tonsils.

The oral tumor size depends on the type and time of diagnosis. Smaller tumors are often benign, while large tumors are disruptive and destructive.

Mouth tumors in dogs are commonly observable in older male dogs of certain breeds. Oral growths cause eating difficulties and must be caught early to avoid dietary issues.

Dog owners are advised to practice semi-annual veterinary checkups for prompt diagnosis and treatment of oral tumors.

“The escalating prevalence of canine oral tumors has emerged as a considerable health concern,” says a study, “Characteristics of Canine Oral Tumors: Insights into Prevalence, Types, and Lesion Distribution,” published in the Journal of Advanced Veterinary and Animal Research in 2023.

Oral tumors in dogs must be differentiated from gingival hyperplasia, an inflammatory swelling of the gums.

What are the other terms for Oral Tumors in Dogs?

Other terms for oral tumors in dogs are oral melanoma, squamous cell carcinoma, or fibrosarcoma. These names describe the types of the top three common malignant oral cancers.

Benign tumors in dogs are called odontogenic tumors. Odontogenic tumors are an umbrella term that includes growths arising from tissues responsible for tooth and periodontium formation.

The group of odontogenic oral tumors in dogs includes peripheral odontogenic fibroma (POF), odontoma, and anacthomatous ameloblastoma. The old term for odontogenic tumors in dogs was epulis.

How do Oral Tumors in dogs differ from other Dental Diseases in Dogs?

Oral tumors in dogs differ from other dental diseases in dogs in terms of causes, action mechanisms, and prevalence. Tumors occur when there is a genetic mutation on a cellular level.

A dental disease develops due to built-up plaque and tartar, pressuring the gums, which respond by retracting and tooth loosening. Oral tumors are common, but dental disease is widespread and affects up to one in three dogs.

Oral tumors and dental disease are similar in two aspects, they cause bad breath and culminate in tooth loss.

Owners are not always able to differ dental disease in dogs from oral tumors, especially in the early phases, and veterinary attention is imperative.

How do Oral Tumors in Dogs develop?

Oral tumors develop slowly or quickly from various mouth tissues. Dogs start developing oral neoplasia after 9 or 10 years of age. The gums are the most common stemming point, but the periodontium, tongue, and tonsils are also affected.

Mouth masses in dogs are malignant or benign. Malignant cancers are locally invasive and tend to spread, forming metastases. Benign growths are not invasive and do not spread.

How common are Oral Tumors in Dogs?

Oral tumors in dogs are common. Oral neoplastic masses account for 6 to 7% of all canine cancer cases, according to a study, “CT Features of Malignant and Benign Oral Tumors in 28 Dogs,” published in Veterinary Radiology & Ultrasound in 2021.

Oral tumors are malignant or benign. The top three cancers in the dog’s mouth are melanoma, squamous cell carcinoma, and fibrosarcoma. The most common benign tumor is odontogenic.

The incidence of oral tumors is 4.9 per 1,000 dogs (0.5%), reports a study, “Demographics of dogs and cats with oral tumors presenting to teaching hospitals: 1996–2017,” published in the Journal of Veterinary Science in 2020.

Oral tumors are common in cats. Cancer of the oral cavity is the fourth most frequent type of feline cancer, according to an article “Oral Cavity Tumors” published by Cornell University.

What breeds are more prone to developing Oral Tumors?

The breeds that are more prone to developing oral tumors are listed below.

Poodles: Poodles of all sizes (miniature, medium, and standard) are prone to various types of oral tumors.
Shih Tzus: Canine oral tumors of malignant and benign origin are prevalent among Shih Tzu breed members.
German Shepherds: German Shepherds are one of the top three dog breeds affected by oral tumors.

What do Oral Tumors in Dogs look like?

Oral tumors in dogs look like small, painless lumps or growths in the oral cavity. Tumors vary in appearance, appearing as white or red masses resembling small ulcers or raised nodules on the gums, tongue, or inner cheeks. Pet owners asking, “What does a tumor look like on a dog?” must be vigilant and consult a veterinarian if they notice abnormal growths or lesions on the dog that indicate the presence of cancer.

What are the common types of oral tumors in dogs?

The most common types of oral tumors in dogs are listed below.

Malignant Melanoma: A pigmented and highly aggressive malignant tumor that spreads to the local lymph nodes and lungs.
Squamous Cell Carcinoma: A red and fleshy malignant tumor with inflammatory and ulcerative properties that invades the surrounding bones.
Fibrosarcoma: A connective tissue tumor that is locally invasive but slow to spread to distant tissues and form metastases.
Anacthomatous Ameloblastoma: A common type of benign odontogenic tumor that is locally aggressive and causes severe bone damage.
Odontogenic Tumors: A group of benign tumors stemming from tissues responsible for tooth and periodontium formation.
Osteosarcoma: An excruciating form of bone cancer affecting the dog’s upper (maxilla) or lower jaw (mandible).

1. Malignant Melanoma

Malignant melanoma is an aggressive cancer rising from melanocytes or pigment-containing cells. Oral malignant melanoma, or OMM, is locally aggressive and quickly spreads to the lungs and lymph nodes.

OMM has a guarded prognosis compared to other tumors. The cancer has spread by the time of diagnosis and has a recurring tendency. Surgery combined with radiation, chemo, or vaccines are suggested management options.

2. Squamous Cell Carcinoma

Squamous cell carcinoma is a malignant skin tumor stemming from squamous cells. The risk of SCC occurrence is associated with sun exposure, unlike other oral tumors.

SCC in the dog’s lip or mouth is red and fleshy in appearance, with a high inflammatory and ulcerative potential.

Oral squamous cell carcinoma has a very low metastasis rate. The prognosis for dogs with oral SCC is good following surgical removal.

3. Fibrosarcoma

Fibrosarcoma in dogs, known as FSA, is a connective soft tissue cancer. Oral fibrosarcoma is malignant and locally invasive.

Dogs with oral fibrosarcoma have a good prognosis. FSA is slower to spread to distant organs than other oral cancers.

Surgery and radiation are the treatment of choice for oral fibrosarcoma, and the treatment is curative in some cases.

4. Acanthomatous Ameloblastoma (Canine Acanthomatous Epulis)

Acanthomatous ameloblastoma (AA) is a gingival tumor that develops from the odontogenic epithelium. AA is locally invasive but generally benign, so it does not spread.

Dogs develop acanthomatous ameloblastoma on the lower jaw (mandible) and the upper jaw (maxilla) in rare cases. Acanthomatous ameloblastoma was formerly called epulis.

Acanthomatous ameloblastoma is curable with surgery alone or in combination with radiation compared to other tumors.

5. Odontogenic Tumors

Odontogenic tumors in dogs are neoplastic growths arising from tissues that form the teeth and periodontal structures. The top three odontogenic tumors are acanthomatous ameloblastoma, peripheral odontogenic fibroma, and odontoma.

Peripheral odontogenic fibromas occur singularly, grow slowly, are not aggressive, and tend to be large. Odontomas are rare, slow-growing, and prevalent in younger dogs.

Odontogenic tumors are more challenging to diagnose than other oral neoplasia because they are radiolucent and resemble cysts on X-rays. Surgery alone is curative in most cases.

6. Osteosarcoma

Osteosarcoma in dogs is a very aggressive and painful type of bone cancer. Oral OSA develops on the upper or lower jaw.

Osteosarcoma of the mouth is widespread among German Shepherds, Greyhounds, Doberman Pinschers, Golden Retrievers, Great Danes, and Boxers.

Mandibular osteosarcoma is more common in dogs. Maxillary osteosarcoma is very rare and has a high recurring tendency compared to other oral cancers.

What are the Causes of Oral Tumors in Dogs?

The causes of oral tumors in dogs are listed below.

Genetics: Oral masses are prevalent among certain dog breeds, indicating a genetic component in tumor development.
DNA Mutations: DNA mutations are the basis of every tumor, causing otherwise normal cells to start changing, dividing, and spreading uncontrollably.
Environmental Factors: Environmental factors, such as UV light and exposure to known carcinogens, contribute to cancer.
Viruses: The papillomavirus causes benign tumors in the mouth in puppies and adult dogs with compromised immunities.

What are the Symptoms of Oral Tumors in Dogs?

The symptoms of oral tumors in dogs are listed below.

Excessive Drooling: Dogs with oral tumors exhibit hypersalivation or excessive drooling. The mass presence in the mouth triggers increased saliva production.
Bloody Saliva: Oral tumors develop ulcers and bleed. The blood mixes with the saliva, causing bloody saliva. Hemoptysis is the medical term for bloody saliva.
Bad Breath: Bad breath, or halitosis, is a common problem in dogs with oral tumors, as benign and malignant masses contain dead fleshy tissue.
Face Pawing: Oral tumors are irritating and make dogs uncomfortable. Dogs respond by pawing at the face to remove the source of irritation and discomfort.
Facial Asymmetry: Large oral masses put pressure on the surrounding structures and, in severe cases, result in loss of facial asymmetry.
Trouble Eating: Mouth tumors are painful and, in some cases, cause difficulty eating. Large masses physically obstruct normal food intake.
Weight Loss: The trouble eating in advanced cases of oral tumors culminates in severe weight loss and emaciation.

Can oral tumors in dogs cause bad breath?

Yes, oral tumors in dogs can cause bad breath. Oral tumors contain dead tissue and have a repulsive rotten meat-like smell. The smell spreads in the dog’s mouth, causing bad breath or halitosis.

Call the veterinarian and schedule an appointment if dealing with halitosis. Bad breath in dogs is a sign of an underlying health problem.

Is nosebleeding a common symptom of oral tumors in dogs?

No, nosebleeding is not a common symptom of oral tumors in dogs. Mouth bleeding or bloody saliva are frequent in dogs with oral masses. Mouth tumors bleed when the dog accidentally bites them.

Nosebleeds or epistaxis are common in dogs with nasal cancers. Tumors in the nasal cavity cause nose bleeding or bloody drooling if the dog swallows some blood.

When do Oral Tumors in Dogs Symptoms usually occur?

Oral tumors in dogs symptoms usually occur when the mass is large enough to cause problems. Food dropping and reluctance to eat are among the first signs of oral issues.

Dogs are relatively tolerant to pain and do not show signs of distress in the early phases. Oral tumors are periodically advanced at the time of diagnosis, and others are not.

Contact a veterinarian if a dog suddenly starts exhibiting disturbing symptoms suspected of oral masses.

What are the Risk Factors for Oral Tumors in Dogs?

The risk factors for oral tumors in dogs are listed below.

Age: Oral cancer occurs in dogs of all ages but appears to be more common in senior dogs over 11 years of age.
Sex: “Male dogs appear to be twice as likely to develop oral cancer than female dogs,” according to Malcolm Weir, DVM, in an article “Oral Tumors in Dogs - An Overview,” published in VCA Hospitals in 2023.
Breed: Oral tumors are prevalent among certain breeds, such as Boxers, Dachshunds, Retrievers, Poodles, and Scottish Terriers.

What are the complications of Oral Tumors in dogs?

The complications of oral tumors in dogs are listed below.

Ulceration: Oral tumors are prone to breaking open or ulcerating, followed by bleeding and pain.
Infections: The dog’s mouth is not sterile, which predisposes oral tumors to infections, which leads to bad breath and clinical manifestation.
Tooth Loss: Oral tumors that spread and affect the jaw bones weaken the roots of the teeth, causing early tooth loss.
Malnutrition: Dogs with oral tumors have trouble eating, which causes weight loss and malnutrition in the long run.
Metastasis: Cancerous tumors of the dog’s mouth tend to spread to distant tissues and organs, forming metastases.

How are Oral Tumors in Dogs diagnosed?

Oral tumors are diagnosed based on fine needle aspiration and biopsy. Fine needle aspiration (FNA) takes a cell sample directly from the tumor with a small-gauge needle and a syringe. The sample is analyzed under a microscope.

Biopsy is recommended if the FNA results are not conclusive. The veterinarian surgically cuts a portion of the tumor to collect a tissue sample for biopsy. The sample is prepared and evaluated under a microscope.

The veterinarian orders blood work, chest X-rays, abdominal ultrasound, aspirates or biopsies from local lymph nodes, and advanced imaging techniques (MRI and CT scan) to determine the tumor stage.

Where can you seek a diagnosis for Oral Tumors in dogs?

You can seek a diagnosis for oral tumors in dogs at the general veterinarian, veterinary dentist, or oncologist.

The general veterinarian or dentist visualizes the oral mass and performs tests to evaluate the type of growth. The vet alternatively refers the dog to an oncologist for a specific diagnosis.

Oral tumors are easy to detect because the dog’s mouth is routinely inspected during vet exams. A pathologist analyzes the collected growth samples under a microscope.

What are the treatments for Oral Tumors in dogs?

The treatments for oral tumors in dogs are listed below.

Surgery: Surgical tumor resection is the gold standard for oral growth in dogs. The procedure depends on the extent of the tumor and entails extensive and complex approaches such as mandibulectomy (removal of the lower jaw), maxillectomy (removal of the upper jaw), or glossectomy (removal of the tongue).
Radiation Therapy: Radiation therapy is normally combined with surgery and works against various cancers. Melanoma and squamous cell carcinoma are sensitive to radiation, while fibrosarcomas are radioresistant and do not respond to radiotherapy.
Chemotherapy: Chemotherapy is not the first treatment choice for dogs with oral cancer due to its varying effectiveness. Commonly used chemotherapeutics include Palladia, bleomycin, cisplatin, and carboplatin.
Vaccine: The FDA licensed a melanoma vaccine called Oncept® in 2010. Oncept® contains tyrosinase, a specific protein found in melanoma cells, and works for advanced cancer cases. The vaccine prolongs the survival rate when combined with surgical resection or radiation.

Can oral tumors be cured?

Yes, oral tumors can be cured. Mouth tumors that are caught early and treated correctly have a good prognosis. Small tumors that have not spread are curable.

Oral tumors are found in the early stages because the dog’s lips and mouth are easy to examine during regular checkups. Practice frequent veterinary exams to catch oral problems early.

Can CBD oil help treat oral tumors in dogs?

Yes, CBD oil can help treat oral tumors in dogs. CBD, or cannabidiol, is a natural hemp extract. CBD is not a cure for cancers, but it aids in the treatment, relieves the symptoms, and improves the dog’s quality of life.

Cannabidiol has anti-cancer properties, promoting the death of cancer cells and preventing tumor spread and growth. Combined with chemo and radiation, CBD boosts their efficacy.

CBD alleviates pain, supports relaxation, and increases appetite, hence improving the quality of life in dogs with oral cancer.

Discuss the benefits of CBD oil treatment for oral tumors with the veterinarian. CBD is natural and safe for dogs of different ages and breeds.