Fatty Tissue Tumors (Lipomas) in Cats

Key Takeaways

Fatty tissue tumors are masses of cells which develop under the skin in cats and are primarily composed of fat. 

• They are soft to the touch, round, and not anchored, so they tend to move freely when pressed

• The most common form is benign and known as a lipoma

• The main symptom is the presence of a round, soft mass under the skin

• Diagnostics include a microscopic examination of cells aspirated from the tumor, biopsy, diagnostic imaging, and bloodwork

• Treatment can include surgery and radiation though in some cases no treatment may be required

• The prognosis for a fatty tissue tumor is generally favorable as they are most often benign

• Prompt veterinary attention is recommended because malignant and aggressive tumors may have the same initial presentation as benign ones

A Closer Look: What are Fatty Tissue Tumors in Cats?

There are four main types of fatty tissue tumors;

Lipomas: Benign masses of fat cells are the most common form of fatty tissue tumor.

Diffuse Lipomatosis: Rare cases where lipomas merge with the surrounding tissues, creating undefined boundaries between the tumors and surrounding tissue.

Infiltrative Lipomas: Fatty tissue tumors which infiltrate nearby skin or muscle. They may be benign or malignant, metastasis of this form is rare.

Liposarcomas: The rarest form. Liposarcomas are malignant tumors which are able to metastasize to other areas.

Risk Factors

This condition is uncommon and most cases are benign. It is always best to have a tumor evaluated to find out if it is malignant or has metastasized. 

Severity of the tumor is determined by the size, type, and location of the mass. Symptoms vary accordingly.

The majority of fatty tissue tumors occur under the skin around muscle tissue and not internally. Most commonly they occur on the chest, abdomen, front legs, and sides of the torso. They tend to range from small to medium size and occur as individual tumors. Cases of large or multiple tumors may indicate a more serious variation of fatty tissue tumor.

Possible Causes

The underlying cause of lipomas is not well understood at this time.

Main Symptoms

The primary and often only symptom is a soft, round, easily moveable lump under the skin. The lumps tend to appear suddenly and do not grow or change significantly. In cases where rapid growth or changes are observed, this is usually indicative of a more serious type of fatty tissue tumor.

Testing and Diagnosis

After a physical examination and medical history, a number of tests can be performed to determine the tumor type and look for metastasis, including:

• Microscopic examination of cells aspirated from the mass

• Biopsy

• Bloodwork

• Diagnostic imaging

Steps to Recovery

If the tumor is determined to be benign and not causing physical distress, no action may be required. Surgical removal is the primary treatment when intervention is required. In cases where surgery is not an effective choice, radiation can be used to minimize size and metastasis.

Prognosis is generally favorable for fatty tissue tumors. Recurrence is rare following surgical removal, but formation of new/multiple tumors is common.


The condition is not preventable but risk can be minimized by remaining observant of changes in the skin and seeking veterinary attention promptly. Staying up to date with routine veterinary examinations helps to identify health conditions early and improve outcomes. Fatty tissue tumors are not contagious.

Are Fatty Tissue Tumors Common in Cats?

Fatty tissue tumors are uncommon in cats.

Typical Treatment

• Surgery

• Radiation

• Monitoring

Want to speak to a vet now?

Book an appointment

Time for a check-up?

Start a video chat with a licensed veterinary professional right now on Vetster!

Book an online vet