Lipomas and liposarcomas in dogs

As dogs age, many of them seem to become prone to developing various small lumps and bumps under the skin, which can often be a cause of concern to the caring owner. Small, fatty lumps under the skin often take the form of a condition common to older dogs called lipomas; and while these can be unsightly and sometimes need treatment if they interfere with free movement or otherwise cause a problem, lipomas are generally completely harmless. However, there is another condition, called liposarcomas, which is similar in appearance to lipomas. These are rather more serious, although thankfully relatively rare. Are you concerned about lumps and bumps on your aging dog’s skin, or has your vet spoken to you about lipomas and liposarcomas? Read on to learn more about both of these conditions.

What is a lipoma?

A lipoma is a non-cancerous (benign) fatty tumour that grows slowly just underneath the surface of the skin. Lipomas can be moved freely, and are generally pliable and squashy to the touch. They can appear on any area of the body, although they are most commonly located around the undercarriage and chest. Lipomas are not dangerous or cancerous, and should not progress or develop into a more serious condition. Generally, lipomas are left untreated, unless they are causing problems with mobility, or your dog persistently scratches at them or they otherwise cause a problem. Lipomas are relatively common in older dogs.

What is a liposarcoma?

A liposarcoma is a lump or bump that is very similar in appearance to a lipoma, and they often appear in the same areas of the body. Liposarcomas can also develop internally, however, and may also appear around the abdominal cavity, other internal organs, and the joints. Liposarcomas are malignant, or cancerous, and prone to spreading and multiplying. They may also metastasize over time to other organs such as the lungs and heart. While liposarcomas appear in the first instance very similar to lipomas, the masses are usually less mobile, firmer, and hard to manipulate, and may cause pain to your dog as well. Liposarcomas are not particularly common in dogs, and certainty nowhere as near as common as lipomas. However, as the two conditions can appear to be very visually similar, testing of the masses is often performed as part of diagnosis to rule out the presence of liposarcomas when lipomas are suspected.

How can you tell a lipoma from a liposarcoma?

The appearance of lipomas and liposarcomas are very similar; generally, the only definitive difference between the two that can be found by a simple physical examination is if the masses appear to feel hard or cause pain when manipulated, which almost certainly marks it as a liposarcoma. However, not all liposarcomas will present in this way, which is why veterinary surgeons will generally recommend further testing to rule out the presence of liposarcomas and play it safe. Testing for liposarcomas may involve blood tests, a fine needle aspirate of one of the masses, or possibly MRI scanning to get a clear picture of the full extent of the growths and their development.

The treatment and prognosis for dogs with lipomas or liposarcomas

Generally, diagnosed lipomas are left untreated, as they do not cause pain or any other problems for the dog affected by them. They may be surgically removed if they interfere with the movement of the limbs or are otherwise causing an obstruction, or if the owner of the dog finds them unsightly, although surgery is usually discouraged for purely cosmetic reasons. While surgical removal of lipomas is generally straightforward and not particularly invasive, it is limited in its effectiveness as lipomas will often return to previously affected areas, and often naturally progress and develop over time across other parts of the dog’s body.Treatment for liposarcomas is rather more difficult, and not always effective. As dogs that develop liposarcomas are often elderly and may not stand up well to the rigours of surgery, and may not gain a significant improvement in their quality of life in the long term after liposarcoma removal, sometimes palliative care and painkillers are recommended while the disease runs its course. This sadly does often lead to the eventual demise of the affected dog, or the decision to euthanize the dog being made further down the line when their quality of life begins to suffer significantly.If your vet does recommend treatment of liposarcomas and you are happy to go ahead with this, surgical removal of the masses is the usual course of action, providing that the mass or masses in question have clearly defined margins, are in an area of the body that is operable, and are not too far advanced. An alternative to surgery that may be indicated, particularly if surgical removal is not viable, is radiation therapy or chemotherapy, again depending on the location(s) size and amount of the masses present. Unfortunately, liposarcomas do have a habit of re-growing, and so any treatment method may only serve to give a temporary respite from the development of the tumours and how they affect the dog in question.

Can you do anything to prevent lipomas or liposarcomas?

Unfortunately, the simple answer to this question is ‘no.’ Lipomas and liposarcomas are not conditions that have any specific known cause or trigger, and are considered to be conditions that come about in some dogs as a natural effect of aging. However, making sure that your dog is fit, healthy, active, and fed a balanced diet is always a good idea, as this will give them the best chance of fighting off any developing condition or being able to deal with the development and treatment of any problems that do arise along the way.