What does a tumor look like on a dog? 3 Common Locations and Their Symptoms

Discovering an unusual lump or bump on your beloved canine companion can be alarming for any pet owner. Dog tumors vary widely in appearance, location, and severity, making it crucial to understand what to look for during routine checks of your pet’s body.

Early detection of dog tumors significantly improves treatment outcomes and prognosis. This comprehensive guide will help you identify different types of dog tumors, recognize warning signs, and know when to seek veterinary care or surgery for suspicious growths on your four-legged friend.

What are Dog Tumors?

Dog tumors are abnormal growths of cells that can develop in any part of a canine’s body. These growths occur when cells divide uncontrollably, forming masses of tissue that serve no physiological purpose and may interfere with normal bodily functions. Dog tumors can develop at any age, though they’re more common in middle-aged to older dogs. These abnormal growths may be external (visible on the skin or just underneath it) or internal (developing within organs or body cavities), making some easier to detect than others during home examinations.

4 Common Types of Dog Tumors

• Benign Tumors: These non-cancerous growths typically grow slowly, don’t spread to other parts of the body, and rarely cause life-threatening problems unless they press on vital organs. Common benign tumors include lipomas (fatty tumors), sebaceous adenomas, and histiocytomas.
• Malignant Tumors: These cancerous growths tend to grow rapidly, can invade surrounding tissues, and may spread (metastasize) to other parts of the body. Malignant tumors often require more aggressive treatment approaches.
• Mast Cell Tumors: Among the most common skin tumors in dogs, these can vary dramatically in appearance and behavior. They typically appear as raised, sometimes reddish bumps that may fluctuate in size.
• Squamous Cell Carcinoma: This type of skin cancer often appears as firm, raised, wart-like growths or as crusty, bleeding sores that don’t heal. They commonly develop in areas with less hair and more sun exposure.

3 Major Locations of Common Tumors in Dogs

Skin and Subcutaneous Tumors

Skin and subcutaneous (just under the skin) dog tumors are the most commonly detected growths in dogs because they’re visible or can be felt during petting or grooming. These dog tumors typically present as lumps, bumps, or masses on or just beneath the surface of the skin. They may be soft or firm, movable or fixed, and can vary in size from tiny nodules to large masses.

4 Common Types of Skin Tumors in Dogs:

• Lipomas: These common benign fatty tumors feel soft and movable under the skin. They typically grow slowly and aren’t painful when touched, though they can become quite large. Lipomas most often develop on the chest, abdomen, or legs.
• Mast Cell Tumors: These can look like many other skin tumors but often appear as raised, red, itchy bumps that may fluctuate in size. Some may ulcerate and bleed, while others remain covered with normal skin. These tumors can be very unpredictable in their growth pattern.
• Warts (Papillomas): These viral-induced growths appear as small, cauliflower-like projections often found around the mouth, eyes, or feet. They may occur in clusters and can sometimes resolve on their own, particularly in younger dogs.
• Melanomas: On the skin, these appear as dark brown to black raised masses, though some may be pink or red. When found on hairless or lightly haired areas, they may resemble moles that change in size or appearance.

Oral and Facial Tumors

Dog tumors in and around the mouth area are particularly concerning in dogs as they can interfere with eating and may go unnoticed in early stages. These growths can develop on the gums, tongue, lips, or inside the cheeks and may be associated with increased drooling, difficulty eating, or bad breath.

4 Common Types of Oral and Facial Tumors in Dogs:

• Oral Melanomas: These appear as raised, often pigmented (dark brown to black) masses in the mouth, though some may be pink or red. They can grow rapidly and often cause bad breath, difficulty eating, or blood-tinged saliva.
• Squamous Cell Carcinoma: In the mouth, these tumors typically appear as red, irregular growths that may ulcerate and bleed. They commonly develop on the gums or tonsillar area and can cause difficulty swallowing or reluctance to eat hard food.
• Epulides: These benign gum growths appear as firm, pink masses along the gumline, often near the front teeth. While typically non-cancerous, they can grow large enough to interfere with eating or may become infected if traumatized during chewing.
• Facial Swellings: Tumors affecting the bones or sinuses of the face may present as asymmetrical swellings, eye protrusion, or nasal discharge. These symptoms warrant immediate veterinary attention as they can indicate aggressive tumors.

Mammary Tumors

Mammary (breast) tumors are common in unspayed female dogs, particularly those spayed after their first heat cycle. These dog tumors develop in the mammary glands along the belly, appearing as firm nodules or larger masses near or around the nipples. Early detection through regular belly checks is essential for successful treatment.

3 Common Types of Mammary Tumors in Dogs:

• Benign Mammary Tumors: These appear as small, well-defined nodules that move freely when touched. They typically grow slowly and remain confined to a single mammary gland.
• Malignant Mammary Tumors: These may grow rapidly, feel firm or hard, and can attach to surrounding tissues, making them less movable. They may also cause the overlying skin to become red, ulcerated, or inflamed, and might affect multiple mammary glands.
• Inflammatory Mammary Carcinoma: This aggressive form causes the mammary tissue to become markedly swollen, red, and warm to the touch. The affected area often has a distinctive “orange peel” appearance and develops rapidly, requiring immediate veterinary attention.

8 Signs You Need Immediate Veterinary Care

When it comes to dog tumors, certain warning signs indicate the need for urgent medical attention. Don’t delay making an appointment if you notice any of these concerning symptoms:

• Rapidly growing masses – Any lump that appears suddenly or grows quickly (noticeable changes within days or weeks) should be evaluated promptly. Aggressive dog tumors often grow much faster than benign growths.
• Bleeding or ulcerated growths – Dog tumors that bleed, develop open sores, or don’t heal properly may indicate malignancy. These open wounds can also lead to infections that complicate treatment.
• Pain or discomfort – If your dog yelps, snaps, or shows signs of pain when a growth is touched, or if they’re constantly licking or chewing at a specific area, immediate care is needed. Pain is often associated with inflammatory or invasive tumors.
• Changes in behavior or bodily functions – Lethargy, loss of appetite, difficulty breathing, persistent coughing, abnormal urination or defecation patterns, or unexplained weight loss alongside the presence of a growth warrants immediate attention. These symptoms may indicate internal tumors affecting organ function.
• Multiple new growths appearing simultaneously – The sudden appearance of several new lumps or bumps is unusual and concerning. This pattern may suggest systemic conditions like lymphoma or mast cell disease.
• Growths in concerning locations – Dog tumors in areas like the eyes, mouth, paws, or genital regions can quickly impact quality of life even if small. These locations have limited space for growth and can rapidly affect important functions.
• Changes in existing lumps – Any significant change in color, texture, size, or firmness of an existing growth should be evaluated. These changes may indicate a previously benign mass has become more aggressive.
• Firm, fixed masses – Growths that feel hard and appear firmly attached to underlying tissues, rather than freely movable, often indicate more concerning types of dog tumors that may be invasive.

5 Treatment Options for Dog Tumors

10 Tips for Prevention

While not all dog tumors can be prevented, regular monitoring and certain lifestyle choices can help with early detection and potentially reduce cancer risks. Follow these steps to be proactive about your dog’s health:

• Perform monthly body checks – Thoroughly examine your dog’s entire body once a month, feeling for any new lumps, bumps, or changes to existing growths. Use a gentle but firm touch to feel through the coat and along the skin surface in a systematic pattern.
• Create a body map – Document any existing lumps with notes about size, location, appearance, and texture. This reference helps you notice changes more quickly and provides valuable information to share with your veterinarian.
• Schedule regular veterinary exams – Maintain bi-annual or annual checkups even when your dog seems healthy. Veterinarians can detect subtle changes or early signs of dog tumors that might be missed during home examinations.
• Spay female dogs early – Having female dogs spayed before their first heat cycle dramatically reduces their risk of developing mammary tumors later in life. This simple step can decrease mammary cancer risk by up to 95%.
• Consider genetic predispositions – Research whether your dog’s breed has higher risks for specific tumor types. Boxers, Golden Retrievers, and Bernese Mountain Dogs, for example, have higher cancer rates than some other breeds.
• Limit sun exposure – Protect dogs with light-colored or thin fur from excessive sun exposure, particularly on their nose, ears, and belly. These areas are more susceptible to squamous cell carcinoma, especially in dogs with light pigmentation.
• Provide a healthy diet – Feed a balanced, high-quality diet appropriate for your dog’s age and activity level. Some studies suggest connections between certain dietary factors and cancer risk, though research is ongoing.
• Maintain a healthy weight – Keep your dog at an appropriate weight through proper diet and regular exercise. Obesity has been linked to increased cancer risk in both humans and dogs.
• Reduce environmental toxins – Limit exposure to potential carcinogens such as lawn chemicals, tobacco smoke, and industrial pollutants. Use pet-safe lawn treatments and avoid smoking around your pets.
• Monitor senior dogs more closely – Increase the frequency of home examinations for dogs over seven years old. Cancer risk increases significantly with age, making vigilance even more important for senior pets.

Conclusion

Finding an unusual growth on your dog can be frightening, but being informed about the various appearances of dog tumors empowers you to take quick, appropriate action. Remember that early detection significantly improves treatment outcomes, making your regular home checks an essential part of responsible pet ownership.

If you notice any concerning lumps, changes in your pet’s behavior, or other symptoms discussed in this article, don’t hesitate to schedule an appointment with us at Potranco Veterinary Hospital. Our experienced team is ready to provide compassionate care for your beloved companion. Visit our Facebook page for more educational content about pet health, and check out our glowing reviews on Yelp to see why so many pet parents trust us with their furry family members.