Skin & Coat

Lumps and Bumps and Cysts, Oh My! What To Do When You Find A Mass On Your Dog

While it may be shocking and frightening when you’re petting your dog (like you always do) and find a lump or bump where it doesn’t belong, these are actually quite common in dogs, and not always something to worry about. Before you panic, read this article below from Dr. Mark Thompson of to learn what do you when you find a mass on your dog.

Lumps and Bumps and Cysts, Oh My! What To Do When You Find A Mass On Your Dog

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.


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.

Read more about what to do if you find a mass on your dog here. Have you ever found an unusual lump or bump on your dog? Tell us your story in the comments below!



  1. Doris Crabtree

    Oct 7, 2016 at 8:10 pm

    My 16 year old Chihuahua has a lump that has dropped down tonight.there was 2 now they dropped down and there is a large one. Its under her at her end almost between her legs.
    Please help

  2. María Rivas

    Sep 2, 2016 at 2:43 pm

    I notice lump on My malteses dog irritaded and painfull
    Lucía its her name im worry shee its My lífe but My económica situación its Not that great Please let me know If its any please that can help me a low Cost

  3. Amy mcinerney

    Jul 15, 2016 at 5:02 pm

    My 9 week old chihuahua puppy has a small lump on her belly and feels like it may have PUSS! I’m scared for her please tell me what I should do or if it should be a concern..its not hot red or irritated it’s just a lump smaller than a dime and may have puss

  4. Mindy

    Jul 9, 2016 at 9:36 am

    I noticed I lump on my dogs head right over her right eye .. It’s the size of grape and it’s under the skin it’s not red it doesn’t bother her there’s no puss are opening or anything .. Sometimes it’s gets bigger and her eye starts to close A little bit and then the next day it’s completely gone I may be a couple days later . Does anybody have any idea what it could be

  5. letha

    Jan 1, 2016 at 7:37 am

    My 2 year old lab mix has a lump on the underside of her tail and I am concerned. Shes otherwise very healthy, active, and the lump doesn’t seem to bother her and hasn’t changed in size but I am concerned. I am worried the Vet may want to surgically remove it but I am very limited financially and couldn’t afford surgery right now. I am torn because I love my dog and want whats best for her. Any financial advice is appreciated.

  6. letha

    Jan 1, 2016 at 7:33 am

    My dog is a lab mix who has a lump on the underside of her tail. It hasn’t changed in size and doesn’t seem to bother her but I’d like to get it checked out by the vet but I’m worried they may have to remove it surgically and I am very limited financially and I can’t afford any surgical procedures for my dog but I love her so much and want whats best for her. Any suggestions for financial help?

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