Skin Lumps and Bumps in Dogs: What You Should Know

Medically Reviewed by Amy Flowers, DVM on May 14, 2023
3 min read

You’re on the couch, cozied up with your canine buddy, and you feel a bump. You try to remember when you last nuzzled this exact little spot. And before you know it, your mind is racing with questions. Is this lump new? What is it?

Quickly, this leads you to the ultimate concern: Could it be cancer? Without a vet’s expertise or test results, it's easy for our minds to get carried away and think the worst.

Most lumps are fatty tumors, though. These are benign, meaning not cancerous. Fewer than half of lumps and bumps you find on a dog are malignant, or cancerous. Still, they can look the same from the outside, so it’s hard to tell.

Unless you’re sure about the cause of a lump or bump, bring your dog in for an exam. If you see fast growth, redness, swelling, pus, an opening, or if the dog is in pain, make that appointment even sooner.

The same goes for lumps that are in certain areas, like the face or paws, where surgery -- if needed -- is more complicated, the bigger the growth.

Your vet will want to know:

  • If the lump appeared suddenly
  • Whether its shape, color, or size has changed
  • Whether your dog’s behavior, such as their appetite or energy level, is different.

Often, the vet will remove some cells from the lump with a fine needle. They'll then look at them under the microscope. Sometimes they can tell right away if it’s a fatty tumor or a different type of tumor, especially if any suspicious cells are found that require further testing.

If it’s too hard to tell, your vet will take a small tissue sample from the lump and send it out for a biopsy. In a few days, you'll find out if it's cancerous. If so, surgery can usually remove the lump.

The bigger concern is if the cancer has already spread to other parts of the body. If so, your pet may need radiation or chemotherapy, or both.

The more common lumps and bumps in dogs include:

  • Fatty tumors, also known as lipomas, happen most often in middle-aged or older dogs, especially around the ribs, although they can show up anywhere. They're considered a natural part of aging. Any breed can have them, but larger dogs and those who are overweight are more prone to them. 
  • A sebaceous cyst is a blocked oil gland that looks like a pimple. When it bursts, a white, pasty substance comes out.
  • Warts, also called viral papillomas, are caused by a virus and can be found around the mouths of young dogs. They'll go away by themselves. Older dogs might need surgery to remove them.
  • An abscess is a buildup of pus under the skin. It can be caused by an infection or a bite from an insect or other creature.
  • A mast cell tumor is the most common skin cancer in dogs. They’re most often found in boxers, Boston terriers, Labradors, beagles, and schnauzers.

If your dog has a lump, even if you find out it isn't cancerous, keep a close eye out for others, and have new ones tested.

If your pal has lots of bumps and lumps, your vet might make a chart of their locations and sizes to make it easier to keep track of what’s new and what’s changed.

You can do this yourself, too. A convenient time to check your dog’s body is during grooming. The more familiar you are with their body, the quicker you’ll know if something isn’t quite right. Plus, more petting means more TLC, and what’s not to love about that?