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.
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