Lumps and Growths in a Dog's Mouth: Causes & Treatments

Dogs, like people, can develop lumps or bumps as they age, including inside their mouths. This article explores the common types of oral lumps in dogs, from benign to malignant, helping you recognise signs and understand when veterinary care is needed.

Benign Lumps in the Mouth of Dogs

Some lumps in your dog's mouth are non-cancerous and may not pose an immediate threat but still require monitoring and veterinary evaluation.

Epulis (Gum Boils)

Epulis, commonly called gum boils, are the most frequent benign growths. These lumps usually share the gum's colour and have a smooth surface. They often appear between the teeth—typically between the canine or incisor teeth—and can be rounded or stalk-like.

They are more common in dogs over six years old and prevalent in brachycephalic breeds such as pugs, boxers, and bulldogs. As they grow, epulides may interfere with eating, cause drooling, bad breath, bleeding, or even tooth misalignment.

If you notice a lump like this, it is important to have your vet examine it promptly. Surgical removal is typically recommended if the growth causes discomfort or functional issues.

Viral Papillomas

Viral papillomas are contagious lumps transmitted through direct contact between dogs, usually affecting young dogs under two years old before their immune system matures.

These growths often resemble cauliflower clusters but can also be smooth. Fortunately, viral papillomas generally resolve on their own within six months, although they must be monitored due to a small chance of malignancy.

Malignant and Potentially Malignant Oral Growths

More serious are oral cancers, which fall mainly into three types: melanomas, squamous cell carcinomas, and fibrosarcomas.

Melanomas

Oral malignant melanoma is the most common cancer type in a dog's mouth and arises from pigment-producing cells (melanocytes). It often appears on the lip, gum, soft palate, or tongue. Older dogs and breeds with pigmented mouths like Chow Chows are more at risk.

Symptoms can include difficulty eating, bad breath, facial swelling, and mouth bleeding. Melanomas are aggressive, tending to spread rapidly to lymph nodes and lungs.

Squamous Cell Carcinomas

Squamous cell carcinomas, more common in cats but occasionally in dogs, develop in the gums and are locally aggressive. These tumours can cause bad breath, pain, drooling, and trouble eating. Early detection and surgical removal often result in good outcomes.

Fibrosarcomas

Fibrosarcomas appear as red boils or ulcers on the mouth's fibrous tissues, often ulcerating and bleeding. They tend to grow slowly but invasively and can eventually spread. Treatment may be effective if caught early.

Other rarer malignancies include mast cell tumours, lymphomas, and osteosarcomas.

When to See a Vet

Any new lumps, swelling, bleeding, bad breath, difficulty eating, or changes in your dog's mouth warrant a veterinary examination. Early diagnosis can improve treatment success and quality of life.

Your vet may perform a thorough oral exam, take dental X-rays, and biopsy suspicious lumps to determine their nature. Treatment ranges from surgery for benign or localised growths to more specialised cancer therapies if needed.

Paying attention to your dog's oral health supports their wellbeing and helps catch issues before they worsen.