Sebaceous Adenomas

Photo Credit: Sumner Fowler

One cannot discuss lumps and bumps in dogs without talking about sebaceous adenomas. These are, far and away, the most common benign skin tumors in dogs. Most dogs will develop at least a couple of them by the time they are senior citizens.

Sebaceous glands are microscopic structures found just beneath the skin surface. They secrete an oily substance called sebum that is transported to the skin surface via microscopic ducts. Adenomas can arise from the gland or the duct, and can develop anywhere on a dog’s body.

Sebaceous adenomas tend to be small, no more than ¼ to ½ of an inch in size. They may appear round or they can have a wart-like appearance. These benign growths occur primarily in middle-aged and older dogs. Any breed can develop sebaceous adenomas, but certain breeds are particularly predisposed: English Cocker Spaniels, Cocker Spaniels, Samoyeds, Siberian Huskies, Alaskan Malamutes, West Highland White Terriers, Cairn Terriers, Dachshunds, Miniature Poodles, Toy Poodles, Shih Tzus, Basset Hounds, Beagles, and Kerry Blue Terriers.

Because of their benign nature, the vast majority of sebaceous adenomas require no treatment whatsoever. Just about as soon as two or three are surgically removed, two or three more will develop. Surgically chasing sebaceous adenomas accomplishes nothing more than turning a dog into a patchwork quilt. There are some exceptions to the general rule of leaving sebaceous adenomas alone, and they are as follows:

– Surgical removal is warranted for those sebaceous adenomas that recurrently bleed or become infected because of self-trauma (the dog bites or chews at them), or because they get in the way of the groomer’s clippers.

– Some sebaceous adenomas secrete oodles of sebum creating the constant appearance of an oil slick on the dog’s hair coat. The grease rubs off on hands, furniture, clothing, and anything else the dog contacts. No fun!

– Some sebaceous adenomas are pretty darned unsightly, looking like warty little aliens poking through the hair coat. Although this is not bothersome for the dog, it can pose a significant psychological issue for the person living with that dog.

– If a mass believed to be a sebaceous adenoma is growing or changing in appearance, it is important to ask your veterinarian to have another look. What was thought to be a benign adenoma may be its less common cancerous cousin, a sebaceous carcinoma.

Does your dog have any sebaceous adenomas?

Best wishes,

Nancy Kay, DVM

Diplomate, American College of Veterinary Internal Medicine
Author of Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life
Author of Your Dog’s Best Health: A Dozen Reasonable Things to Expect From Your Vet
Recipient, Leo K. Bustad Companion Animal Veterinarian of the Year Award
Recipient, American Animal Hospital Association Animal Welfare and Humane Ethics Award
Recipient, Dog Writers Association of America Award for Best Blog
Recipient, Eukanuba Canine Health Award
Recipient, AKC Club Publication Excellence Award
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Please visit to read excerpts from Speaking for Spot and Your Dog’s Best Health.   There you will also find “Advocacy Aids”- helpful health forms you can download and use for your own dog, and a collection of published articles on advocating for your pet’s health. Speaking for Spot and Your Dog’s Best Health are available at,, local bookstores, and your favorite online book seller.

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9 Comments on “Sebaceous Adenomas

  1. Hi Vicki. While sebaceous adenomas and follicular cysts are both benign skin tumors that can look an awful lot alike, they actually arise from different structures. The recommendations I made pertaining to sebaceous adenomas would apply to follicular cysts as well. Thanks for your question!

  2. Is the sebaceous adenoma the same or similar to a follicular cyst? I don’t usually do anything about the cyst unless it burst and the toothpaste thick gunk oozes out. However, I do wonder if this is the same as your topic? My dogs are a 14 yr old spaniel mix and a 9 yr old Tibetian Spaniel.

  3. Great question Robin. Cats do get sebaceous adenomas, but as common as they are in dogs is as uncommon as they are in cats.

  4. Hi Mary. In this case, it sounds like all turned out well even though a fine needle aspirate was not performed. As you likely know, in the blog post I wrote a few weeks ago (Lumps and Bumps) I discussed the reasons why fine needle aspirates are important. It is not wrong to surgically remove a sebaceous adenoma, particularly if it is bleeding or bothering the dog in some way. It sounds like a smart move for your Norwich Terrier!

  5. I found a pimple on my dog’s butt, just millimeters above her anus, last August. It was very small and seemed innocuous. I watched it for a month, intending to take her in to have it checked if it changed, but nothing happened. I then forgot about it (I know that was a mistake).

    In April, while cleaning her butt, I saw some blood on the cloth. Looking closer, I saw that the “pimple” was now a little larger (still tiny), and looked rougher, more like a little wart now. I immediately took her into my vet, who advised removing it before it got any bigger, since it was in such as sensitive area. He as able to do so without cutting into the muscle around the anus at all, and she healed very quickly.

    The lump turned out to be a benign sebaceous adenoma. I’ve been wondering ever since if I did the right thing having it removed right away. I tend to think so, since it could have cause problems even if benign because of location, and because it can be difficult to distinguish these from anal carcinomas based on biopsy alone. My hesitation is whether a needle aspirate should have been done first (the lump was small enough that this might have been difficult). Any thoughts?

    Dog is a Norwich Terrier, 11 lbs, just turned 10 years old.

  6. Hi Diane. Good suggestion. I purposefully did not include a photo of a sebaceous adenoma simply because one cannot “tell a book by its cover.”. I would hate to think that, because of a photo I might have included, someone might have ignored a cancerous growth because it looked like the benign sebaceous adenoma I showed in one photo. Make sense?

  7. My 7 1/2 year’s young Bernese Mountain Dog, Skye, has developed a sabacious adenoma on her back near her hip. Having lost 2 Berners to The Big C, I about freaked. My wonderful (calm) veterinarian, Dr. Patti Tuck, at Alpine Animal Hospital in Gaylord, MI drew serum and assured me that nothing warrented surgery. I am so relieved. Best to have all lumps and bumps checked as soon as they are evident. Proper treatment certainly prolongs life in even the worst case scenario.
    Patty Aarons