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What Causes Fatty Tumors in Dogs: 3 Major Causes You Should Watch Out For

By July 1, 2025August 26th, 2025No Comments
What Causes Fatty Tumors in Dogs: 3 Major Causes You Should Watch Out For

Have you noticed a soft, movable lump under your dog’s skin? You might be dealing with fatty tumors in dogs, one of the most common benign growths affecting our canine companions. These lumps, while typically harmless, can cause concern for pet owners who want the best for their furry friends.

If you’re worried about any unusual lumps on your dog, don’t wait to get answers. Schedule an appointment with AZ Vet Direct today for a professional evaluation and peace of mind about your pet’s health.

What are fatty tumors in dogs?

Fatty tumors in dogs, medically known as lipomas, are non-cancerous growths composed of fat cells that develop beneath the skin. These soft, round masses are typically movable when touched and grow slowly over time. While they’re usually harmless, some fatty tissues can grow large enough to affect your dog’s mobility or comfort.

5 Common Locations

  • Chest and Ribcage Area: Fatty tumors in dogs frequently develop along the chest wall and between the ribs. These locations often go unnoticed until they reach a noticeable size during petting or grooming.
  • Abdomen and Belly: The soft tissue of the abdomen provides an ideal environment for lipoma formation. These tumors can sometimes be mistaken for weight gain if they grow gradually.
  • Upper Legs and Shoulders: Many dogs develop lipomas where the legs meet the body. These areas experience constant movement, making larger tumors more problematic for mobility.
  • Neck and Back: Lipomas along the spine and neck are common, especially in older dogs. They typically feel like soft, oval-shaped masses that move freely under the skin.
  • Armpits and Groin: These warm, protected areas often harbor fatty tumors in dogs. Due to the sensitive location, even small tumors here can cause discomfort during movement.

3 Primary Causes of Fatty Tumors in Dogs

Genetic Predisposition

Certain breeds inherit a tendency to form lipomas more frequently than others, with the condition often running in family lines. Dogs with parents or siblings who developed fatty tumors have a higher likelihood of experiencing them too. Understanding your dog’s genetic background can help you stay vigilant for early detection.

What dog breeds are prone to fatty lumps?

  • Labrador Retrievers and Golden Retrievers: Their genetic makeup and tendency toward weight gain make them particularly susceptible to fatty growths, especially as they age.
  • Doberman Pinschers: Lipomas often appear in middle age and can occur in clusters rather than as single tumors.
  • Miniature Schnauzers: They often develop lumps earlier than larger breeds, sometimes as young as five years old.
  • Cocker Spaniels: Their long, flowing coats can hide smaller tumors, making regular grooming checks essential.
  • Weimaraners: Their tumors tend to grow larger than in other breeds, requiring closer monitoring.

Aging and Lifestyle

As your dog ages, their metabolism slows down, making fat cell accumulation more likely. Senior dogs, typically those over eight years old, show increased susceptibility to developing fatty tumors. The aging process affects how the body processes and stores fat, creating conditions favorable for lipoma formation. Combined with decreased activity levels in older dogs, these metabolic changes significantly increase the risk of fatty tumor development.

Obesity

Overweight dogs face a substantially higher risk of developing fatty tumors due to excess fat cell accumulation throughout their body. When dogs carry extra weight, their fat cells can cluster abnormally, forming the benign tumors we recognize as lipomas. Poor diet quality, overfeeding, and lack of portion control contribute to both obesity and lipoma formation. Maintaining your dog at a healthy weight through proper nutrition and regular exercise can help reduce the likelihood of fatty tumor development.

How Do You Get Rid of Fatty Tumors in Dogs

  1. Schedule a Veterinary Consultation: Your first step should always be getting a professional diagnosis. Your vet will perform a physical examination and may recommend a fine needle aspiration to confirm the tumor is indeed a benign lipoma and not something more serious.
  2. Discuss Monitoring vs. Treatment: Many fatty tumors in dogs don’t require immediate removal. Your vet might suggest a “watch and wait” approach, where you’ll monitor the tumor’s size and check for any changes during regular visits.
  3. Consider Surgical Removal: If the fatty tumor interferes with your dog’s movement, grows rapidly, or causes discomfort, surgical removal becomes necessary. This outpatient procedure involves removing the entire tumor and the surrounding capsule under general anesthesia.
  4. Explore Non-Surgical Options: For dogs who aren’t good surgical candidates due to age or health conditions, your vet might recommend alternative treatments. These could include dietary changes to prevent further growth or, in rare cases, radiation therapy for tumors in difficult locations.
  5. Follow Post-Treatment Care: After surgical removal, you’ll need to keep the incision site clean and dry. Your dog will likely wear an e-collar to prevent licking, and you’ll administer any prescribed medications to prevent infection and manage pain.
  6. Implement Prevention Strategies: Once you’ve addressed existing fatty tumors, work with your vet to develop a prevention plan. This typically includes weight management, regular exercise, and high-quality nutrition to minimize the risk of new tumors forming.

Why do you need to remove fatty tumors in dogs?

Mobility Restrictions

When fatty tumors grow in areas like the armpits, groin, or legs, they can seriously impact your dog’s ability to move comfortably. Large tumors create physical obstacles that alter your dog’s natural gait, potentially leading to muscle strain or joint problems. Dogs may begin limping, avoiding certain activities, or showing reluctance to exercise. Over time, these mobility restrictions can lead to muscle atrophy and decreased quality of life.

Rapid Growth Concerns

While most fatty tumors in dogs grow slowly, some can increase in size surprisingly quickly, doubling or tripling within months. Rapidly growing tumors require immediate veterinary attention because this unusual growth pattern could indicate a more serious condition. Fast-growing masses may also outgrow their blood supply, leading to tissue death and potential infection within the tumor. Your vet might recommend removal and biopsy of quickly expanding tumors to rule out malignancy. Early intervention prevents these tumors from reaching sizes that make surgical removal more complicated and risky.

Risk of Rupture

Large fatty tumors in dogs, especially those in high-friction areas, face an increased risk of rupturing through the skin. When tumors rupture, they create open wounds susceptible to serious bacterial infections that can spread throughout your dog’s body. The exposed tissue becomes painful and requires intensive wound management, often more complex than preventive surgical removal would have been. Ruptured tumors may also bleed significantly, creating emergency situations requiring immediate veterinary care. Proactive removal of at-risk tumors prevents these painful complications and protects your dog from unnecessary suffering.

Quality of Life Impact

Beyond physical complications, large fatty tumors can significantly diminish your dog’s overall happiness and comfort. Dogs with sizable tumors may struggle to find comfortable sleeping positions or experience constant irritation from tumors rubbing against surfaces. The psychological impact includes increased anxiety, decreased playfulness, and withdrawal from normal activities. Some dogs become self-conscious about their appearance, especially if tumors are highly visible.

Conclusion

Understanding fatty tumors in dogs empowers you to make informed decisions about your pet’s health. While these benign growths are common, especially in senior dogs and certain breeds, proper monitoring and timely intervention when necessary can ensure your dog maintains a high quality of life.

Don’t let concerns about fatty tumors go unchecked. Schedule an appointment with AZ Vet Direct today for expert evaluation and treatment options. Follow us on Facebook, Instagram, and TikTok for more helpful pet health tips and updates on keeping your furry family members healthy and happy.

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