Fatty Tumor in Dogs (Lipoma)

  • Occurrence: common
  • Location of disease: General/Whole body
Author: Dr. med. vet. Gisa Löwe | Last modified: 11.08.2026
Open table of contents

When to visit the vet?

Home care monitor at home and contact your vet if worse

?

If the condition worsens / symptoms persist, consult a veterinarian.

Download/Print

Definition

A lipoma is a benign fatty tumor that commonly occurs in dogs. It consists of an accumulation of fat cells that form a soft, movable lump under the skin.

BASICS/CAUSES:

A lipoma develops through the uncontrolled growth of fat cells. These cells group together and form an encapsulated mass that primarily develops in the subcutaneous tissue. The exact cause of this growth is not fully understood; however, genetic factors play a significant role.

Genetic predispositions are a key factor in the development of lipomas. Certain dog breeds such as Labrador Retrievers, Dobermans, and Dachshunds are more frequently affected, suggesting that hereditary factors play a role. Additionally, older dogs appear to be more susceptible to developing lipomas, indicating age-related changes in fat metabolism.

Hormonal influences and the dog’s overall metabolism can also contribute to the development of lipomas. Changes in the regulation of fat cells or in energy metabolism could promote the growth of such fat deposits. Furthermore, being overweight could increase the risk of developing lipomas, as excess fatty tissue can promote the growth of fat cells.

Another possible factor is chemical exposure or environmental pollution. Certain chemicals or pollutants could indirectly influence the growth of fat cells. Although this has not been extensively researched in dogs, there is evidence that environmental factors could contribute to the development of lipomas.

Das Wichtigste auf einen Blick

A lipoma is a benign fatty tumor in dogs, often perceived as a soft, movable lump under the skin. Although the exact cause is unknown, factors such as genetics, age, and body weight play a role. Diagnosis is usually made through a physical examination and fine-needle aspiration, where tissue samples are analyzed under a microscope to confirm the benign nature. Occasionally, biopsies or imaging techniques such as ultrasound are necessary to more accurately determine the size and location of the lipoma. Treatment is often not required unless the lipoma affects the dog’s quality of life. In such cases, surgical removal may be considered, which is usually straightforward. The prognosis for dogs with lipomas is excellent, as they rarely pose a health threat. After a certain period, the risk of recurrence is low, although new lipomas may develop in other locations. Regular veterinary check-ups are important to respond early to new growths. Preventive measures such as a balanced diet and regular exercise can help minimize the risk. A healthy environment and considering genetic factors when choosing a pet can also be beneficial.

Ursachen

  • Unknown, but factors such as genetics, age, and body weight may play a role

Symptoms

Rare symptoms:

Lipomas are usually painless and rarely cause discomfort. They appear as soft, movable lumps under the skin that can be easily shifted when touched. Most lipomas are oval or round and have a smooth surface.

The size of a lipoma can vary. Some are small and barely noticeable, while others can become significantly larger. In rare cases, a lipoma can become so large that it impairs the dog’s movement or becomes uncomfortable, especially if it is located on the limbs or in the chest area.

Although lipomas are mostly benign, any newly discovered lump on a dog’s body should be examined by a veterinarian to rule out other potentially malignant tumors. Lipomas themselves are largely not dangerous, but an accurate diagnosis is necessary to ensure it is not another type of growth.

Diagnose

The diagnosis of a lipoma is usually made through a physical examination and a fine-needle aspiration. The veterinarian will feel the soft, movable structure of the lipoma and use a needle to take a small tissue sample for examination under a microscope. This method helps distinguish harmless fat cells from other cell types.

In some cases, a biopsy may be required if the fine-needle aspiration does not provide a clear result or if there are doubts about the benign nature of the tumor. A biopsy provides a larger tissue sample for a more precise analysis.

Imaging techniques such as ultrasound or X-ray can be used to determine the size and location of the lipoma, especially if it is deep in the tissue or near important structures such as muscles or nerves.

Therapie

In most cases, a lipoma does not require treatment unless it impairs the dog’s quality of life or causes discomfort. Surgical removal may be considered for large or bothersome lipomas. The procedure is usually straightforward, as lipomas are often well-encapsulated and easy to remove.

The decision to remove a lipoma depends on several factors, including its location, size, and potential impact on the dog’s well-being. Before surgery, the veterinarian will perform a comprehensive assessment to ensure the procedure is necessary and safe.

After removal of the lipoma, the tissue is often sent for histopathological examination to confirm the benign nature of the tumor and ensure that no malignant changes are present.

Prognose und Nachsorge

The prognosis for dogs with lipomas is generally excellent. Since lipomas are benign tumors, they rarely pose a threat to the dog’s health. After removal of a lipoma, the risk of recurrence at the same site is low, although dogs that have developed one lipoma may be susceptible to forming new lipomas at other body sites.

Most dogs recover quickly from surgical removal and can resume normal activities soon after the procedure. Regular veterinary check-ups are important to monitor the dog’s health and respond early to new growths.

Prävention

While there are no specific measures to completely prevent lipomas, some general health practices can minimize the risk. A balanced diet and regular exercise can help maintain the dog’s ideal weight and avoid being overweight, which could reduce the risk of developing lipomas.

Regular veterinary check-ups are important for detecting potential changes in the dog early on. A healthy environment with minimal exposure to potential environmental toxins can also be helpful, although the direct influence of such factors on the development of lipomas is not fully understood.

Since genetic factors play a role, it is advisable to consider the health history of the parents when choosing a new pet, especially for breeds predisposed to lipomas. Breeders who focus on genetic health can help reduce the risk of passing on a tendency for lipomas.

Ausblick auf aktuelle Forschung

A lipoma is a benign tumor of the fatty tissue. In small animal medicine, it is common mainly in dogs; typical features are slow growth and a soft, easily movable swelling under the skin. Precisely because the common lipoma is usually biologically harmless, research today focuses less on a “cure” and more on how to recognize problematic forms early. These include, above all, infiltrative lipomas, which can grow into muscles or other tissue, as well as the reliable differentiation from liposarcomas. (vcahospitals.com, pubmed.ncbi.nlm.nih.gov)

A second research focus is the identification of risk factors and their development. Large population-based studies show that age, being overweight, and certain breeds are associated with an increased risk of lipoma. This increasingly directs research toward metabolism, adipose tissue biology, and possible genetic influences. (pubmed.ncbi.nlm.nih.gov)

More precise imaging is also particularly important. Ultrasound, CT, and MRI are intended to better predict whether a mass should be surgically removed and how deep it extends. The outlook is therefore more diagnostic and prognostic: in the future, lipomas will probably not be treated completely differently, but rather classified more individually, avoiding unnecessary surgeries and identifying problematic variants more reliably. (pubmed.ncbi.nlm.nih.gov)

Frequently Asked Questions (FAQs)

1. What is a lipoma in dogs?
A lipoma is a benign tumor consisting of mature fat cells (adipocytes). It is one of the most common skin tumors in dogs. Lipomas are typically soft, easily movable, painless, and usually grow slowly. They can occur as single nodules or as multiple lumps.
2. Which dogs frequently develop lipomas?
Lipomas occur primarily in older, overweight dogs. Breeds with a predisposition include Labrador Retrievers, Dobermans, Golden Retrievers, Schnauzers, and Weimaraners. Female dogs also fall ill slightly more often than males. The average age at diagnosis is over eight years.
3. Are lipomas dangerous?
Common lipomas are benign and do not metastasize. Problems arise mainly due to size and location: very large lipomas can hinder movement or press on nerves and vessels. Rarely, infiltrative lipomas occur, which grow into adjacent muscle tissue, or malignant liposarcomas, which often present clinically in a similar way.
4. How is the diagnosis made?
Diagnosis is made through fine-needle aspiration and cytological examination. The detection of mature fat cells without atypia is typical. In cases of atypical localization, rapid growth, fixation to the underlying tissue, or uncertainty in the cytology, a surgical biopsy with histological examination should be performed.
5. Does every lipoma have to be removed?
Small, superficial lipomas that do not affect the dog do not necessarily have to be removed. Surgery is indicated if the lipoma hinders movement, is located in an unfavorable spot, grows quickly, or is cosmetically or hygienically bothersome. Infiltrative lipomas should be removed early while they are still small.
6. How is a lipoma operated on?
Simple subcutaneous lipomas can be easily shelled out from their capsule. For infiltrative lipomas, a wide excision into healthy tissue is necessary, which can be technically demanding. In particularly difficult locations, such as the armpit, a preoperative CT provides a better basis for planning.
7. Can lipomas come back?
Completely removed, classic lipomas usually do not reform in the same place. However, new lipomas at other sites are common in predisposed dogs. Infiltrative lipomas have a significantly higher local recurrence rate if they were not completely resected.
8. How do you distinguish a lipoma from a liposarcoma?
Clinically, both can look similar; however, rapid growth, fixation to the underlying tissue, and an atypical consistency are more suggestive of a liposarcoma. Only histology after surgical removal is definitive. Liposarcomas are rare but can be very aggressive locally and, in rare cases, metastasize.
9. Does weight loss help against lipomas?
In overweight dogs, moderate weight loss is generally sensible and can at least prevent existing lipomas from enlarging. Complete regression is rare, but smaller lipomas can become significantly softer and less noticeable.
10. How often should lipomas be checked?
Known lipomas should be measured and documented once a year as part of a routine examination. In the event of significant growth, changes in consistency, or discomfort for the dog, a new fine-needle aspiration is advisable. Every new lump should be assessed separately, regardless of existing lipomas.

Literatur

  • O’Neill, D. G., Corah, C. H., Church, D. B., Brodbelt, D. C., & Rutherford, L. (2018). Lipoma in dogs under primary veterinary care in the UK: Prevalence and breed associations. Canine Genetics and Epidemiology, 5, Article 9. https://doi.org/10.1186/s40575-018-0065-9
  • Pegram, C. L., Rutherford, L., Corah, C., Church, D. B., Brodbelt, D. C., & O’Neill, D. G. (2020). Clinical management of lipomas in dogs under primary care in the UK. Veterinary Record, 187(10), e83. https://doi.org/10.1136/vr.105804
  • Lamagna, B., Greco, A., Guardascione, A., Navas, L., Ragozzino, M., Paciello, O., Brunetti, A., & Meomartino, L. (2012). Canine lipomas treated with steroid injections: Clinical findings. PLoS ONE, 7(11), e50234. https://doi.org/10.1371/journal.pone.0050234
  • Volta, A., Bonazzi, M., Gnudi, G., Gazzola, M., & Bertoni, G. (2006). Ultrasonographic features of canine lipomas. Veterinary Radiology & Ultrasound, 47(6), 589–591. https://doi.org/10.1111/j.1740-8261.2006.00191.x
  • Spoldi, E., Schwarz, T., Sabattini, S., Vignoli, M., Cancedda, S., & Rossi, F. (2017). Comparisons among computed tomographic features of adipose masses in dogs and cats. Veterinary Radiology & Ultrasound, 58(1), 29–37. https://doi.org/10.1111/vru.12445
  • Crowley, J. D., Hosgood, G., Crawford, N. V., & Richardson, J. L. (2020). Computed tomographic findings, surgical management and postoperative outcomes of large intermuscular lipomas in the hindlimb of 11 dogs. Australian Veterinary Journal, 98(4), 135–139. https://doi.org/10.1111/avj.12901
  • Feng, Y., Kent, M. S., Théon, A. P., & Hansen, K. S. (2023). Conventionally fractionated radiation therapy is associated with long-term survival in dogs with infiltrative lipomas. Journal of the American Veterinary Medical Association, 261(11). https://doi.org/10.2460/javma.23.05.0288
  • Hauser, A., Thorsen, L., Boss, M.-K., & Wormhoudt Martin, T. (2024). A retrospective study evaluating the outcomes of conventionally fractionated radiation therapy as a treatment for infiltrative lipomas in twenty-one dogs. Veterinary and Comparative Oncology. https://doi.org/10.1111/vco.13001