What Does That Lump on My Pet Mean?

person with bright red nail polish gently holds a chihuahua in her lap, on its back. The dog looks relaxed.

You’re cuddling with your pet, and something feels a bit off. Uh oh — is that a lump? How long has it been there? Where did it come from? Should I be concerned? Keep in mind that the majority of lumps and bumps found on pets are benign (non-cancerous) and can be treated. Read on to find out what that lump may mean.

How Are Lumps Diagnosed?

When you first discover a lump or bump, you may want to take note of how suddenly it appeared, if the shape, color, or size has changed, and if your pet’s behavior has changed. You can let your veterinarian know your observations.

It is important to have your vet diagnose the lump for you. When your veterinarian attempts to diagnose the lump, they may collect a tissue sample from the lump for testing. Testing methods include:

  • Skin scrape or impression smear: A microscope is used to examine a sample from the surface of the lump.
  • Fine needle aspirate: A needle is inserted into the lump to extract cells for evaluation.
  • Biopsy: A small surgical procedure is performed to obtain tissue samples. The samples are then reviewed by a pathologist.

Once the lump has been tested, your veterinarian can make an accurate diagnosis.

What Are the Different Types of Lumps?

There are numerous types of lumps, but some common types include fatty tumors (lipomas), cysts, abscesses, mast cell tumors, and fibrosarcomas.

Fatty Tumors (Lipomas)

Fatty tumors, also known as lipomas, are generally benign. They are commonly found in older pets and are considered a natural part of aging. These soft, rounded, lumps are usually non-painful and they can appear on any part of the body. Although removal usually isn’t necessary, they can be removed if they are an annoyance for your pet.

Cysts

A cyst can develop for a few reasons. Sometimes a cyst is composed of dead cells or sweat. These types often heal themselves. Others can be caused by blockages in hair follicles, skin pores, or oil glands. Cysts are usually oval-shaped and firm, but softer in the middle. They can appear at any age on any part of the body. If the cyst does not disappear on its own, removal may be an option.

Abscesses

Abscesses are also benign and can form from a mild injury, such as an insect bite or a scratch from another animal. Once an injury has healed over, pus can be prevented from draining, and this causes an abscess. They are usually red and swollen. It can be unpleasant for your pet, but surgery and antibiotics are treatment options.

Mast Cell Tumors

Mast cell tumors consist of mast cells, which are a type of white blood cell. They can appear anywhere on the body, sometimes alone or in multiples. They may be red, swollen, and itchy. These tumors are a common form of skin cancer in dogs, but are rarely cancerous in cats. Fortunately, surgery is a treatment option.

Fibrosarcoma

A fibrosarcoma develops in the connective tissue of the skin. It consists of fibroblast cells. These tumors are malignant and tend to develop on the limbs. Although they can be more invasive, they may be treated with surgery. A combination of surgery, radiotherapy, and chemotherapy may also be an option.

How Are Lumps Treated?

Once a lump has been diagnosed, your veterinarian can explore the next steps with you. Treatment methods will differ based on the type of lump and each individual pet’s situation.

Treatment may include:

  • Antibiotics
  • Topical or systemic parasiticides
  • Topical or systemic anti-inflammatory medicine
  • Surgery
  • Chemotherapy
  • Radiation

Although it can be a little worrying to find a lump on your pet, keep in mind that the majority of lumps and bumps are benign. Contact your vet to diagnose a lump or bump. Treatment is possible and your vet will ensure that your pet gets the care they need.