Should You Remove Your Dog’s Epulis? Understanding CAA
Canine acanthomatous ameloblastoma (CAA), formerly known as acanthomatous epulis, is a benign yet
locally aggressive oral tumor commonly found in dogs. Although not metastatic, its invasive behavior makes prompt diagnosis and complete removal critical to your dog’s long-term health and quality of life.
What Is CAA?
CAA is a tumor that originates in the
odontogenic epithelium—tissue found in the gingiva of the dog's mouth, particularly in tooth-bearing areas of the jaw. While it may appear innocuous at first, CAA shows high rates of bone invasion and destruction if left untreated.
Which Dogs Are at Risk?
Although any breed may develop CAA, it is most common in
middle-aged to older dogs. Certain breeds display a higher prevalence:
- Golden Retrievers
- Cocker Spaniels
- Akitas
- Shetland Sheepdogs
Symptoms of Epulis / CAA
Owners may notice one or more of the following signs:
- Visible gingival mass (exophytic growth)
- Oral bleeding or ulceration
- Facial swelling
- Tooth loosening or displacement
- Difficulties in eating, chewing, or swallowing
- Excessive drooling and bad breath
- Incidental discovery during dental exams
Diagnosing CAA
A thorough veterinary assessment involves:
- Clinical exam of the oral cavity
- Biopsy and histopathological analysis for confirmation
- Imaging, such as dental X-rays or CT scans, to assess bone involvement
- Optional cytologic or immunohistochemical tests for differential diagnosis
Histologically, CAA presents with islands and sheets of squamous epithelial cells with unique nuclear features, indicating its odontogenic origin. Immunohistochemical markers like
HRAS p.Q61R can further distinguish it from more dangerous malignancies.
Treatment Options
Complete surgical excision is the gold standard for treating CAA. Marginal excision or curettage often results in recurrence rates as high as 91%. Effective surgical interventions include:
- Wide-margin excision: Involves removal of the tumor with 1–2 cm of surrounding healthy tissue
- En bloc resection: Recommended when the tumor is extensive; may involve partial jaw removal
- Rim excision: May be appropriate for small tumors (<2 cm) with minimal bone involvement
Most dogs recover well from surgery, even when part of the jaw is removed. Postoperative quality of life typically remains high, with dogs regaining normal eating and behavior.
Alternative Therapies
Non-surgical interventions are considered under specific circumstances:
- Radiation therapy: Effective but comes with risks such as osteoradionecrosis and secondary malignant transformation. Offers ~80% three-year progression-free survival.
- Intralesional chemotherapy: Less commonly used due to adverse effects like tissue necrosis and poor healing.
Prognosis and Monitoring
The prognosis for dogs with completely excised CAA is
excellent:
- 1-year survival rate of 97–100%
- Majority of recurrences linked to incomplete removal
- Metastasis has not been reported
- Life expectancy usually unaffected if properly treated
After treatment, regular follow-up exams and imaging are recommended to monitor for potential recurrence. However, systemic spread is not a concern with CAA.
The Genetic Angle
Recent studies show that over 60% of CAA tumors harbor activating
HRAS mutations (notably p.Q61R), with some exhibiting BRAF mutations. These findings not only advance diagnostics but also position CAA as a promising large-animal model for studying
RAS-driven tumors in human medicine.
Conclusion: Should You Remove It?
Yes, prompt and complete surgical removal of your dog’s epulis (CAA) is highly recommended. Early treatment prevents bone damage and recurrence and ensures your dog maintains a high quality of life. Consult a veterinary dentist or surgeon with experience in oral tumors to determine the best course of action.
