Skin Growth, Lump, Swelling or Mass in Dogs

Skin growths are lumps of tissue that are within the skin or can be felt under the skin. Dogs can develop small bumps (papules) or larger bumps (nodules) on their skin. These lumps and bumps are fairly common occurrences, especially in the older dog.

Very often the word "lump" brings the word "cancer" to mind. However, there are many other causes of lumps. A skin growth or mass may be a malignant or benign tumor, an abscess, a cyst, a hematoma (blood-filled mass) or a reaction by the skin to an allergen (hives). Lumps are often benign accumulations of fat called lipomas. However, all lumps should be evaluated for the possibility of malignancy.

What to Watch For

Any new lump or bump should be evaluated right away, especially a lump that is rapidly growing, is warm or painful, is ulcerated or bleeding, is irregular in shape or is well attached to the tissues under the skin. Any of the above signs should prompt you to seek veterinary attention.

Diagnosis

Your veterinarian may take a complete history. Expect to answer the following questions:

How long the growth has been there?

Has it gotten larger or smaller or changes in appearance?

Does the lump appear to be attached to the underlying skin?

How fast is it is growing?

Have there been any recent injuries or injections?

Is there only one lump or are there others?

Are there any changes in your pet's behavior, such as eating less, weight loss, vomiting, diarrhea or lethargy?

A complete physical exam will be done. Your veterinarian will pay particular attention to the appearance of the mass, whether it is hot or painful, whether it is within the skin or under the skin, if it is attached to underlying tissues and where it is located on the body. Additional tests may include:

An aspirate of the mass with a small needle may be done to collect cells for staining and examination under a microscope (cytology). This test usually requires no anesthesia and often leads to a diagnosis.

If the mass is ulcerated or draining fluid, a microscope slide may be touched to the fluid to make an impression for microscopic examination.

A biopsy may be taken to send to a veterinary pathologist for examination. The biopsy may involve removing the entire mass or removing a piece of the mass.

A piece of tissue may be submitted for culture if infectious agents such as bacteria or fungi are suspected.

Treatment

Treatment depends on the cause of the mass. There is no specific treatment for all skin growths.

Home Care

Give all medications as instructed and observe masses closely for growth, heat, redness and pain.

If the growth has been removed or biopsied, keep your dog confined to allow for healing. Observe the incision site closely for drainage, swelling, redness, heat or pain.