What Large Bumps on Dogs Can Mean

Large bumps on dogs are common and can be a concern to pet parents. A skin bump in dogs is also referred to as growth, mass, lump, or tumor. Sometimes large skin bumps are felt during routine grooming or petting at home or can also be found by groomers during bathing and grooming.

A large bump in a dog can be anything from a bruise, a benign mass, to a malignant tumor. We will give you some common causes for large bumps in dogs and provide suggestions to help you keep your dog healthy. The biggest concern of pet owners is that the large bump on a dog could be cancer.

Causes of Large Bumps on Dogs

What one person may consider large may be very different from another and may depend on the size of the dog. For example, a 3-inch mass on a 5-pound Chihuahua may be huge relative to the same mass on a 140-pound Mastiff dog. For the purpose of this article, a large bump on a dog is over a couple inches in size. There are many causes for smaller bumps.

Below are some possible causes for large bumps on dogs:

Large scabs – A scab is a rough, dry crust that forms as a protective barrier over a healing cut, laceration, puncture or wound. Some scabs are small but some can be quite large depending on the underlying cause of the wound. Often clipping hair to evaluate this area can help determine if the problem is a tumor or a healing wound. Learn more about home care of a laceration in dogs.
Abscess – An abscess can appear as a large lump. An abscess is a localized pocket of infection that contains pus. Abscesses are caused by bacteria, parasites, or foreign material under the skin and develop quickly. They will generally break open at some point and drain. Your veterinarian may need to evaluate the lump, lance the abscess in some cases, and provide pain medications and antibiotics. The most common cause for an abscess is an infection caused by a bite wound.
Hematoma – A hematoma is a large bruise. Most often this is associated with some trauma such as hit by a car or other type of trauma. Bruising can also occur from abnormal bleeding disorders. Learn more about bruising and bleeding in dogs. Dogs can also get hematomas in their ear flaps from shaking their heads which can be secondary to an ear infection. For more information, please read aural hematomas in dogs.
Fatty mass – Fatty tumors, also called lipomas, are amongst the most common bumps that occur in dogs. Fatty tumors generally soft but can be firm if they are under a layer of muscle. They can be movable or attached. They vary in size but can become very big. For example, a Labrador retriever recently had a lipoma surgically removed that was attached to his right rib cage that weighed over 14 pounds and was a little bigger than a basketball. Fatty tumors are not malignant but can grow to become large and interfere with a function such as walking. Learn more about Fatty cysts in dogs.
Lymph nodes – Some skin lumps are lymph nodes that can be felt under the skin. A common spot for pet owners to feel large lymph nodes are under the chin around the jawline. These lymph nodes are the “submandibular” lymph nodes. There are different causes of lymph node enlargement that can include anything from local infections to cancer.
Benign mass – There are several types of benign skin masses that can become large in dogs. Some are listed above such as abscesses or fatty tumors. It can be impossible to tell the difference between a benign and a malignant lump without additional testing.
Malignant tumor – There are skin tumors that can be malignant. Some can occur in certain areas such as the mammary chain which can be mammary gland tumors. Tumors of the testicles can also occur.
Organ tumors – Tumors of the liver or spleen can occur but generally aren’t obvious by most pet owners. However, some pet owners notice when their dog lays on their side that the abdomen looks distended or appears abnormal. They may even feel an abnormal bump. For more information about a lump that can occur on the spleen or liver – go to Hemangiosarcoma in Dogs.

How to Determine the Cause of a Large Bumps on Dogs

If your dog has a large bump, the best way to help determine the underlying cause is to closely examine the bump. Many times shaving the hair around that area is a big help to allow you to examine the bump and surrounding area. This may be best done with the help of your veterinarian. Your veterinarian may perform the following:

A complete exam. They will want to look at your dog’s eyes, ears, listen to the heart and lungs, and feel the abdomen.
Examine the skin bump. Your vet will evaluate the skin bump noting the size, shape, depth, consistency, location, color and more.
Provide recommendations. Based on the location of the tumor, size, any signs of infections, your vet will provide recommendations for the best approach to your dog’s skin mass. They may recommend an additional test to evaluate the mass such as a fine needle aspirate (FNA), biopsy, or mass removal (lumpectomy”).

Common causes of large bumps on dogs include:

Small Lumps on Dogs

Some dogs may have small lumps. Common small tumors include Mast Cell Tumor, Melanomas, and Histiocytomas. Learn more about What Small Bumps on Dogs Can Mean?

Additional causes of small lumps include:

Sebaceous Cysts in Dogs
Mast Cell Tumor in Dogs
Skin Tags (Acrochordon or Fibroepithelial Polyps) in Dogs
Malignant Melanoma in Dogs
Canine Viral Papillomas (Dog Warts)

Learn more about lumps that are pigmented with this article What Does a Black Lump on a Dog’s Skin Mean? Two additional articles that may be helpful are Skin Cancer in Dogs and Metastatic Neoplasia (Cancer) in Dogs.

We hope this article helps you better understand the causes of large bumps on dogs.

What Large Bumps on Dogs Can Mean

Causes of Large Bumps on Dogs

How to Determine the Cause of a Large Bumps on Dogs

Small Lumps on Dogs

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