Lipomas In Dogs

Lumps and bumps and other growths are a fact of life for many dogs, especially as they grow older. One type of lump that is very common is called a lipoma. Not to be confused with lymphoma, which is cancer of the lymph system, lipomas are fatty lumps on dogs — a fatty accumulation in the form of a mass under the skin.

Simple lipomas are benign. They can appear on various parts of a dog’s outer body but they do not spread. A dog might have one or two lipomas, or several. No particular breed is more susceptible, nor is a dog’s sex a determining factor in whether he or she will have a lipoma.

Pet parents often ask veterinarians to remove these fatty tumors because they can continue to grow. Removal also is typically curative, but that doesn’t mean another lipoma won’t grow in a different spot. Removal of a fatty tumor can be done for cosmetic reasons or because a dog’s quality of life might otherwise be impacted. For example, if a lipoma grows big enough — say, to the size of an orange, and it’s on a dog’s leg — it can hinder the dog’s ability to walk. Lipomas in dogs are not painful, however. It’s also worth noting that a dog does not have to be fat or overweight to develop a fatty tumor.

Other Types Of Fatty Tumors In Dogs

One type of fatty tumor is more troublesome than a simple lipoma, and there is also a type of cancer that develops within fatty tissue:

Infiltrative lipoma: An infiltrative lipoma on a dog is a fatty tumor that is not encapsulated.  As such, it invades into and around other types of tissue locally, such as between fascial plans and into muscle tissue.

Liposarcoma: A liposarcoma is a malignant transformation of fat tissue. They are rare. These tumors can metastasize (spread to other parts of the body) to the lymph nodes and lungs.

Clinical Signs To Look For

A fatty tumor can feel like a water balloon under the skin. They can feel soft and squishy, however other benign and malignant tumors can also feel this way.  They obviously can be detected visually if they are big enough, but you (or a veterinarian) can also feel them while petting your dog or just feeling for bumps and lumps as a regular precautionary practice. If a canine lipoma is in a less obvious spot, such as in the axillary area (the equivalent of an armpit), then the dog’s range of motion might be impacted enough to notice a difference in his or her gait.

Workup & Diagnosis

Since almost all lipomas are on a dog’s outer body, a veterinarian can at least suspect that a lump is a lipoma based on its appearance and feel. A fine needle aspiration would need to be ordered to draw a sample from the lump to determine whether it is indeed benign.

Further testing should be expected if surgical removal is planned, even if a tumor is benign. These tests will help determine whether a dog is in good enough health to handle anesthesia and surgery. Typically included in this workup are bloodwork, including a complete blood count (CBC) and blood chemistry profile; a urinalysis as well as chest X-rays, to make sure the dog does not have an enlarged heart that could add risk to the surgery.

Treatment Options & Prognosis

Fatty tumors can be small, medium, or quite large. They also can range from harmless to cancerous. Treatment options thus run the gamut, from surgical removal to radiation to a wait-and-watch approach:

Surgery: Removing fatty tumors in dogs is a fairly simple surgery for typical lipomas. Such tumors tend to come out all in one piece, and surgery is usually curative. Certain tumor locations make removal more complex — such as if the mass is in the axillary area of a dog’s front leg, where there are important anatomical structures. It is also difficult to remove infiltrative tumors. They do not shell out in one piece, as they intertwine with other tissues, and thus surgery is not typically curative for infiltrative tumors.

Radiation: In instances when surgery is not viable or a tumor is only partially removed, radiation is an additional option. Radiation is designed to significantly damage tumors without damaging the surrounding tissue or organs. There are two types of radiation: conventionally fractionated radiation therapy (CFRT) and Stereotactic Radiation. The key difference is that the latter uses a higher dose of radiation delivered directly to the tumor with an unprecedented level of accuracy, and thus only one to three radiation sessions are needed vs. 15 to 21 with traditional CFRT. The PetCure Oncology team has extensive experience at providing innovative Stereotactic Radiation. Radiation can greatly slow down the growth of tumors, or they may not grow at all. If tumors begin to grow again after a couple of years, the dog can undergo a second round of radiation.

Combination Therapy: For a liposarcoma, your veterinarian may recommend a combination of surgery, radiation therapy and possibly chemotherapy depending on the extent and aggressiveness of this malignant cancer.

Delayed treatment or no treatment: Since lipomas in dogs are sometimes small and grow slowly, veterinarians and pet parents sometimes have a watch-and-wait philosophy. Many may only grow to a certain size then remain in a quiescent phase. At times, fatty tumors left untreated can get too large and could become too big to remove.

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Find A PetCure Oncology Location Near You

PetCure Oncology treats lipomas in dogs and many types of cancer. In addition to offering innovative treatments, our team is compassionate, supportive and professional — all of which is in line with our mission to care for your dog and provide the best quality of life possible while extending his or her life for as long as possible. For more information about PetCure Oncology and our treatment options, find a location near you today.

Types of Cancers in Dogs

If your dog is displaying any symptoms of cancer or has been diagnosed with cancer, sort below by cancer type or tumor location to learn more about the most common types of cancer in dogs and available treatment options. Click on the links for more specific information on treatment and real patient stories.


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