Liposarcoma in cats and dogs

Tumors of the Adipose (Fat) Tissue in Cats and Dogs

Lipomas (benign tumors)
Lipomas refer to benign (noncancerous) tumors of the fat tissue that can be distinguished from the malignant liposarcoma
tumors by cytology or biopsy. They are relatively common in older dogs, especially in subcutaneous locations (the layer of
tissue directly underlying the skin), however, they can also occur in the chest cavity, abdominal cavity, spinal canal, and
the vulva nad vagina of dogs. They rarely cause any symptoms but can become a medical problem once they reach a
size large enough that can compress onto and interfere with adjacent tissues/organs. Once the lipomas begin to cause
medical problems in the pets, they are usually surgically removed which can be followed by radiation therapy to ensure
that the tumor won't grow back.

Intermuscular lipomas are a variant of the subcutaneous lipoma and are located in the intermuscular region of the thigh of
dogs. They can occasionally cause lameness and are recommended to be surgically removed.

Infiltrative lipomas (infiltrative tumors)
This is a relatively uncommon tumor that is differentiated from simple lipoma or liposarcoma by cytology or biopsy . They
are considered benign (noncancerous) and do not metastasize (spread) to distant organs, however, they can invade
immediately adjacent tissues such as muscle, joint capsule or even bone. CT (computed tomography) imaging is used to
better characterize the mass but it can be difficult to distinguish the benign fat tumor from normal fat. Depending on the
location and extent of the tumor, surgical removal with or without radiation therapy has been used in some cases.

Liposarcomas (malignant tumors)
Liposarcoma, a type of soft tissue sarcoma cancers, is an uncommon malignant tumor that originates from fat cells in
older dogs. It is usually reported in subcutaneous locations, especially along the extremities, but can occur in other sites
such as the abdominal cavity or bone. Liposarcomas can be distinguished from lipomas by cytological examination of the
cells under the microscope. These tumors are locally invasive and, unlike lipomas, also have a low potential to spread
(metastasize) to distant organs in the body such as the lungs, liver, spleen, and bone. The prognosis for pets diagnosed
with liposarcoma is good as long as appropriate complete surgical removal has been done.

Are there any clinical trials investigating new treatments?
There are available clinical trials investigating new treatments for soft tissue sarcomas in pets. To learn more about
veterinary clinical trials in general, please visit the Pet Clinical Trials section. To learn more about clinical trials open to
enrollment in the United States, please visit the Clinical Trials for Soft Tissue Sarcoma section.

To help Pet Cancer Center conduct more liposarcoma clinical trials across the United States in order to make novel and
more efficacious therapies available to pets, please

Do these tumors cause pain?
It is imperative that pets with cancer are provided with pain medication to relieve discomfort caused by the disease as well
as by the treatments. To learn more, please visit the Cancer Pain Management section.

What food should be fed to pets with cancer?
Pets with cancer need to be fed diets specifically designed to support a cancer patient. To learn more, please visit the
Cancer Nutrition section.

Additional online resources

Sources:

Withrow Stephen J, and David M. Vail. Small Animal Clinical Oncology. St Louis: Saunders Elsevier, 2007.
Morrison Wallace B. Cancer in Dogs and Cats: Medical and Surgical Management. Baltimore: Williams&Wilkins,
1998.