Perianal Gland Tumors In Dogs

Perianal gland tumors are common in intact (not neutered) male dogs. They are extremely uncommon in cats, as cats do not possess the sebaceous glands around the anus that dogs do.

Fortunately, we don’t see many mature dogs who have not been neutered, so this is a fairly uncommon tumor, but I suspect that a dog we saw today, Buckshot, has two.  We will know more when he is biopsied.

When we discuss the advantages of having one’s male puppy neutered we often focus on testicular and prostate health advantages, but reducing the likelihood of perianal gland masses is another very important reason to remove the source of testosterone while one’s dog is very young.

Perianal gland tumors come in two varieties: benign and malignant. Fortunately, most are adenomas, benign growths that originate in microscopic sebaceous (oil) glands in the skin around the anus. That’s the good news. The bad news is that these benign tumors have to be removed before they become unmanageably large and surgery in and around the anus is very tricky. Most general practitioners will refer this surgery patient to a board-certified veterinary surgeon.

Malignant tumors, called adenocarcinomas, tend to be very aggressive and will spread to regional lymph nodes, liver and lungs. If these are caught early, neutering and surgical removal of the growth may be adequate, but if there is metastasis (spread) the prognosis for full recovery is poor.

These tumors may also appear in other areas, including the tail, perineum, prepuce and thigh.

Further, both malignant and benign perianal gland tumors are driven by testosterone, so it is mandatory that dogs be neutered at the time they are anesthetized for biopsy and/or tumor removal.

Perianal gland tumors are different from those arising from anal sacs. We will cover anal sac tumors at a later date.

Happy New Year, Dr. Randolph.


  1. Hi,

    My fixed 7 year old male German shepherd has had issues with his left anal sac in the past, nothing severe but needed it squeezed once because of being irritated. But nothing more then that.

    I took him to the vet because I noticed a bit of blood and the vet said he could feel a small bump near the anal gland I suppose, he didn’t like and wants to check his calcium levels to hopefully rule out cancer and a tumour. My vet seems worried it is at tumour and prescribed antibiotics just in case.

    I’m not sure how to feel. I keep reading online fixed male dogs don’t get this type of tumour or cancer? He seems perfectly healthy and stopped bleeding, slowed down licking and has no other symptoms but I can’t help but feel like he’s going to die on me.

    I suppose I am just looking for some feedback of any sort. The survival for cancer seems so minimal for dogs with this and I feel like he is already dying before he’s even been diagnosed with anything.

    • First, be aware that perianal gland tumors and anal sac tumors are two different things. Their behavior, inciting causes and incidence are different, too. IF CAUGHT EARLY, before metastasis, anal sacculectomy is curative. Calcium level alone won’t tell the whole story. If in doubt, ask your veterinarian for a referral to a board-certified veterinary oncologist for further workup. Thanks for reading, Dr. Randolph.

  2. My 9 year old Yorkie, intact, was diagnosed with a benign perianal adena tumor under his anus. He has had it for about a year and just recently it has
    Grown and a bit infected because he started licking it. The surgery is scheduled to remove the tumor along with castration. Is neutering him really required? Thank you.

  3. my 6 yr old doxie, male, neutered, was just dianosed with anal sac carcinoma….removed 1 week ago…doing great, but there is so much negativity surrounding this ….All his tests came back great, no spread, and biopsy said they got it all, but the tumor was aggressive……options nothing ,but recheck every 3 months…or his choice see a cancer specialist for chemo .
    What would be your suggestions??

  4. Hello, As the others my Jake, 8yr neutered heeler, has been diagnosed with Perianal Adenoma. I took him to the vet to see what the red grape size bump just under the tail was and after a very quick exam, surgery is scheduled.. My question is, he was feeling good before we took him in to the vet and now he is with drawn. He has had 1 Carprofen 75 mg. Is it possible that when the vet checked for the size of the tumor inside his rectum she could have ruptured it and now the fluid is spreading thru his system? He has been health and walks 3 miles a day.. We feed him Costco beef , some table scraps. I am worried that this is a bigger deal then I was lead to believe.. No x-rays or blood work has been done.. I have been told by the vet that they will do all of that at the time of surgery 1 week from today.. Thanks for any insight you have

  5. Hi, Dr. Randolph. My dog has been diagnosed with perianal gland adenocarcinoma. He has two tumors: one is a visible bulge on the left side of the anus, and is what made me take him to the veterinarian. Upon examination and cell pathology we learned that the visible bulge was likely benign. However, there was another tumor on the right side of the anus, inside the canal, that appears to be malignant. His blood work is normal (no heightened calcium!); surgery is recommended. My question: What is the recovery time for this type of surgery?

    • Dana, I’m so sorry to hear that your dog has a malignancy. I hope that the preoperative chest X-ray was negative, too, along with the normal calcium level. I’m also sorry I can’t answer your question about recovery time. In uncomplicated cases of benign tumors that don’t require invasion of the anal sphincter muscles recovery is about two weeks. In your pet’s case, you say that the lesion is “inside the canal.” Are you speaking of the pelvic canal, or is it impinging on the colon? Or, has it invaded the colon? Having to enter the colon the surgery would be much trickier and recovery factors depend heavily on the amount of invasion and the grade of the tumor. There are just too many variables for me to know without having seen your pet, but I’m confident your pet’s doctor can give you a reasonable estimate of postoperative care and duration. Keep us posted on how he does. Best wishes, Dr. Randolph.

  6. Dr. Randolph, I have a friend who has a Norwegian Elkhound, intact male, 9 years young, diet is store-bought kibble, without a history of previous health problems. In the last couple of years, this dog has developed a number of what the owner says are subcutaneous cysts. From her description they may be sebaceous cysts. The dog has had numerous surgeries. Client is considering euthanasia if another surgery is the only alternative. This is a bright, active, vibrant, intelligent dog who is eating, drinking and thriving. She has been given a prescription of life-long antibiotic therapy, with possibly more surgeries ahead. Are antibiotics the only way to maintain this dog, or are there other things to consider or think about? Are there advantages to neutering the dog at this age? Anything new happening in Dermatolgy with these cases? Thank you, Rose

    • Dear Rose,
      There are too many unanswerable questions with the information we have. However, I assume that these cysts have been evaluated by a histopathologist. I would be happy to look at the report(s). The most important factor here is the fact that not all “cysts” are “sebaceous cysts.” Different kinds of cysts are treated differently. The pet could also be referred to a board-certified veterinary dermatologist for evaluation (which would be WAY preferable to euthanasia!).
      Please keep me posted on this case, it would be very sad for him to lose his life.
      Best wishes,
      Dr. Randolph

  7. Hi, Doctor Randolph. My Boston Terrier of 11 years, male, has been diagnosed with a perianal tumour. We took him to a homeopath Saturday to find out if it is benign. We are praying it is, but we are a little apprehensive about removing it. What other options do we have? He doesn’t seem to be in any pain. Will this change? He was neutered years ago. His mum passed way 2 years ago with Cushing’s Disease. Is there any chance this is hereditary? Thank you.

    • No guarantees here, but chances are your prayers will be answered in a positive way. Keep praying, God likes to hear from His people. In the absence of a testosterone source (usually the testicles, but there can be other sources) malignant tumors of the perianal glands usually don’t occur in this area of the body. Other tumors, both malignant and benign, do occur in the absence of testosterone and can occur in the perineum. Please write back and let me and our readers know the results of the biopsy. Best wishes, Dr. Randolph.
      PS: By your use of the words “tumour” and “mum” we know you’re not American. May we ask where you’re writing from?

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