Atypical Lipomatous Tumors and Liposarcoma in Cats and Dogs
Learn about adipose tissue tumors in cats and dogs, including the differences between lipoma, infiltrative lipoma, and liposarcoma, as well as the diagnosis and treatment process.
Atypical Lipomatous Tumors in Cats and Dogs
When you notice a soft lump under your cat’s or dog’s skin, one of the first possibilities that often comes to mind is a lipoma, commonly known as a “fatty lump,” which is a benign tumor.
Indeed, lipomas are benign tumors of adipose tissue that are particularly common in dogs. However, not every soft lump is a lipoma.
Tumors arising from adipose tissue can have different biological characteristics, including infiltrative lipomas and liposarcomas.
What Is a Lipoma?
A lipoma is a benign tumor that develops from adipose tissue.
It is particularly common in older dogs. Lipomas are generally soft, movable masses that can be felt beneath the skin.
However, the appearance of lipomas can resemble that of other tumors. Therefore, it is not possible to make a definitive diagnosis based solely on physical examination.
Fine-needle aspiration and cytological evaluation can help prevent a lipoma from being mistaken for another type of tumor.
Is Every Soft Lump a Lipoma?
No.
Some tumors can mimic a lipoma. In particular, mast cell tumors may appear similar to lipomas in some cases.
Therefore, it is not appropriate to assume:
“It is definitely a fatty lump because it is soft, movable, and painless.”
Veterinary evaluation and, when necessary, cellular examination are required to determine the nature of a mass.
What Is an Infiltrative Lipoma?
Unlike conventional lipomas, infiltrative lipomas are tumors that can extend between surrounding tissues and muscle structures.
They generally do not metastasize but can behave invasively at the local level. Therefore, accurately determining the tumor margins is important when planning surgical treatment.
What Is Liposarcoma?
Liposarcoma is a malignant tumor that develops from adipose tissue.
It is uncommon in companion animals. In dogs, it can occur primarily in older animals and may develop on the trunk or extremities.
Although liposarcomas generally have a relatively low potential for distant metastasis, they may have a risk of local recurrence. Therefore, evaluation of surgical margins and follow-up are important.
How Are Lipomas and Liposarcomas Distinguished?
It is not possible to reliably distinguish them based solely on appearance.
The evaluation may involve several stages:
Physical examination → Fine-needle aspiration → Cytology → Biopsy/histopathology when necessary → Diagnostic imaging when indicated
Pathological examination is one of the most important sources of information for determining the biological behavior of a tumor.
Which Masses Should Raise Concern?
Masses with the following characteristics should be evaluated, particularly if they are:
Growing rapidly
Becoming firmer
Becoming less mobile
Seemingly attached to deeper tissues
Changing in shape
Recurring after removal
Ulcerated
Bleeding
Affecting the animal’s movement
Causing pain
Nevertheless, even a mass that does not cause any noticeable symptoms may require evaluation.
How Is Treatment Planned?
Lipomas do not always require surgical intervention. The size and location of the tumor, its growth pattern, and its impact on the animal’s quality of life are taken into consideration.
For liposarcomas or tumors with infiltrative characteristics, a more extensive surgical approach may be required. In some cases, additional treatments may also be considered alongside surgery.
For Pet Owners in Istanbul Seeking Information About Masses in Cats and Dogs
For pet owners living in Istanbul, particularly in Ataşehir and surrounding districts, searches such as “my dog has a soft lump underneath the skin,” “my cat has developed a fatty lump,” or “are lipomas dangerous in dogs?” are a natural part of seeking information about their pet’s health.
However, it is not possible to determine through the internet whether a mass is benign or malignant.
The appropriate approach is to have the mass properly characterized and, when necessary, evaluated through pathological examination.
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